Network Working Group L. Ciavattone
Internet-Draft AT&T Labs
Intended status: Standards Track R. Geib
Expires: 8 November 2025 Deutsche Telekom
7 May 2025
Test Protocol for One-way IP Capacity Measurement
draft-ietf-ippm-capacity-protocol-16
Abstract
This document addresses the problem of protocol support for measuring
Network Capacity metrics specified by RFC 9097. The Method of
Measurement discussed there requires a feedback channel from the
receiver to control the sender's transmission rate in near-real-time.
This document defines the UDP Speed Test Protocol for conducting RFC
9097 and other related measurements.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 8 November 2025.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Scope, Goals, and Applicability . . . . . . . . . . . . . . . 4
3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5
4. Parameters, Security Operations, and Optional Checksum . . . 9
4.1. Parameters and Definitions . . . . . . . . . . . . . . . 9
4.2. Security Mode Operations . . . . . . . . . . . . . . . . 9
4.2.1. Mode 0: Optional Unauthenticated Mode . . . . . . . . 10
4.2.2. Mode 1: Required Authenticated Mode . . . . . . . . . 10
4.2.3. Mode 2: Optional Authenticated Mode for Data Phase . 11
4.2.4. Mode 3: Optional Encryption of Control and Status . . 12
4.3. Key Management . . . . . . . . . . . . . . . . . . . . . 13
4.4. Configuration of Network Functions with Stateful
Filtering . . . . . . . . . . . . . . . . . . . . . . . . 14
4.5. Optional Checksum . . . . . . . . . . . . . . . . . . . . 15
5. Test Setup Request and Response . . . . . . . . . . . . . . . 15
5.1. Client Generates Test Setup Request . . . . . . . . . . . 15
5.2. Server Test Setup Request Processing and Response
Generation . . . . . . . . . . . . . . . . . . . . . . . 18
5.2.1. Test Setup Request Processing - Rejection . . . . . . 19
5.2.2. Test Setup Request Processing - Acceptance . . . . . 22
5.3. Setup Response Processing at the Client . . . . . . . . . 24
6. Test Activation Request and Response . . . . . . . . . . . . 25
6.1. Client Generates Test Activation Request . . . . . . . . 25
6.2. Server Processes Test Activation Request and Generates
Response . . . . . . . . . . . . . . . . . . . . . . . . 29
6.2.1. Server Rejects or Modifies Request . . . . . . . . . 29
6.2.2. Server Accepts Request and Generates Response . . . . 31
6.3. Client Processes Test Activation Response . . . . . . . . 32
7. Test Stream Transmission and Measurement Feedback Messages . 32
7.1. Test Packet PDU and Roles . . . . . . . . . . . . . . . . 33
7.2. Status PDU . . . . . . . . . . . . . . . . . . . . . . . 37
8. Stopping a Test . . . . . . . . . . . . . . . . . . . . . . . 43
9. Method of Measurement . . . . . . . . . . . . . . . . . . . . 44
9.1. Notes on Interface Measurements . . . . . . . . . . . . . 44
10. Security Considerations . . . . . . . . . . . . . . . . . . . 45
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11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46
11.1. New System Port Number Assignment . . . . . . . . . . . 46
11.2. New UDPSTP Registry Group . . . . . . . . . . . . . . . 47
11.2.1. PDU Identifier Registry . . . . . . . . . . . . . . 47
11.2.2. Protocol Version Registry . . . . . . . . . . . . . 48
11.2.3. Test Setup PDU Modifier Bitmap Registry . . . . . . 49
11.2.4. Test Setup PDU Authentication Mode Registry . . . . 49
11.2.5. Test Setup PDU Command Response Field Registry . . . 50
11.2.6. Test Activation PDU Command Request Registry . . . . 52
11.2.7. Test Activation PDU Modifier Bitmap Registry . . . . 52
11.2.8. Test Activation PDU Rate Adjustment Algo.
Registry . . . . . . . . . . . . . . . . . . . . . . 53
11.2.9. Test Activation PDU Command Response Field
Registry . . . . . . . . . . . . . . . . . . . . . . 54
11.3. Guidelines for the Designated Experts . . . . . . . . . 55
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 55
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 55
13.1. Normative References . . . . . . . . . . . . . . . . . . 55
13.2. Informative References . . . . . . . . . . . . . . . . . 57
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 58
1. Introduction
The performance community has seen development of Informative Bulk
Transport Capacity definitions in [RFC3148] for Framework for Bulk
Transport Capacity (BTC) [RFC5136] for Network Capacity and Maximum
IP-layer Capacity, and the Experimental metric definitions and
methods in [RFC8337], Model-Based Metrics for BTC.
This document specifies the UDP Speed Test Protocol (UDPSTP) enabling
the measurement of Network Capacity metrics as defined by [RFC9097].
The Method of Measurement discussed there deploys a feedback channel
from the receiver to control the sender's transmission rate in near-
real-time.
This protocol supports measurement features which weren't available
by TCP based speed tests and standard measurement protocols like One
Way Active Measurement Protocol (OWAMP) [RFC4656], Two-Way Active
Measurement Protocol (TWAMP) [RFC5357] and Simple Two-Way Active
Measurement Protocol (STAMP) [RFC8762] prior to this work. The
controlled Bulk Capacity measurement or Speed Test, respectively, is
based on UDP rather than TCP. The bulk measurement load is
unidirectional.
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Apart from measurement functionality, the UDPSTP security features
have been developed following guidance given by the IETF Security
Area and the resulting specification is compliant with state of the
art security implementations. This is a secondary improvement
reached by the UDPST Protocol and may simplify its reuse for other
measurement purposes.
1.1. Terminology
Downstream UDP Speed Test: a client initiated Network Capacity
measurement between a server acting as sender and a client acting as
receiver.
Upstream UDP Speed Test: a client initiated measurement of Network
Capacity measurement between a client acting as a sender and a server
acting as receiver.
1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119], [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Scope, Goals, and Applicability
The scope of this document is to define a protocol to measure the
Maximum IP-Layer Capacity metric according to the Method of
Measurement standardized by Section 8 of [RFC9097]. Some aspects of
this protocol and end-host configuration can lead to support of
additional forms of measurement, such as application emulation
enabled by creative use of the load rate adjustment algorithm.
The goal is to harmonize the specified IP-Layer Capacity metric and
method across the industry, and this protocol supports the
specifications of IETF and other Standards Development Organizations
(SDO's; see, e.g., [TR-471]).
The primary application of the protocol described here is the same as
in Section 2 of [RFC7497] where:
* The access portion of the network is the focus of this problem
statement. The user typically subscribes to a service with
bidirectional access partly described by rates in bits per second.
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3. Protocol Overview
All messages defined by this document SHALL use UDP transport.
The remainder of this section gives an informative overview of the
communication protocol between two test endpoints (without expressing
requirements or elaborating on the authentication and encryption
aspects).
One endpoint takes the role of server, listening for connection
requests on a standard UDP Speed Test Protocol port number from the
other endpoint, the client.
The client requires configuration of a test direction parameter
(upstream or downstream test, where the client performs the role of
sender or receiver, respectively) as well as the hostname or IP
address(es) of the server(s) in order to begin the setup and
configuration exchanges with the server(s). By default, the client
uses the single, standard UDPSTP port number per connection (see
Section 5). If the default port number is not used, the client may
require configuration of the control port number used by each server.
This would be the case, if multiple server instances (processes)
operate on one or more machines.
Additionally, multi-connection (multi-flow) testing is supported by
the protocol. Each connection is independent and attempts to
maximize its own individual traffic rate. For multi-connection
tests, a single client process would replicate the connection setup
and test procedure multiple times (once for each flow) to one or more
server instances. The server instance(s) would process each
connection independently, as if they were coming from separate
clients. It shall be the responsibility of the client process to
manage the inter-related connections: handling the individual
connection setup successes and failures, cleaning up connections
during a test (should some fail) as well as aggregate the individual
test results into an overall set of performance statistics. Fields
in the Setup Request (mcIndex, mcCount, and mcIdent, see Section 6.1)
are used to both differentiate and associate the multiple connections
that comprise a single test.
The protocol uses UDP transport [RFC0768] with two connection phases
(Control and Data). The exchanges 1 and 2 (see below) constitute the
Control phase, while exchanges 3 and 4 constitute the Data phase. In
this document, the term message and the term Protocol Data Unit, or
PDU ([RFC5044]) are used exchangeable.
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1. Test Setup Request and Response: If a server instance is
identified with a host name that resolves to both IPv4/IPv6
addresses, it is recommended to use the first address returned in
the name resolution response - regardless, whether it's IPv4 or
IPv6. Thus the decision on the preferred IP address family is
left to the DNS operator. Support for separate IPv4 and IPv6
measurements or an IPv4 and IPv6 multi connection setup are left
for future improvement. The client then requests to begin a test
by communicating its protocol version, intended security mode,
and datagram size support. The server either confirms matching a
configuration or rejects the connection request. If the request
is accepted, the server provides a unique ephemeral port number
for each test connection, allowing further communication. In a
multi-connection setup, distinct UDP port numbers may be assigned
with each Setup Response from a server instance. Distinct UDP
port numbers are assigned, if all Setup Response messages
originate from the same server in that case.
2. Test Activation Request and Response: after having received a
confirmation of the configuration by a server, the client
composes a request conveying parameters such as the testing
direction, the duration of the test interval and test sub-
intervals, and various thresholds (for a detailed discussion, see
[RFC9097] and [TR-471]). The server then chooses to accept,
ignore or modify any of the test parameters, and communicates the
set that will be used unless the client rejects the
modifications. Note that the client assumes that the Test
Activation exchange has opened any co-located firewalls and
network address/port translators for the test connection (in
response to the Request packet on the ephemeral port number) and
the traffic that follows. See [RFC9097] for a more detailed
discussion of firewall and NAT related features. If the Test
Activation Request is rejected or fails, the client assumes that
the firewall will close the address/port number pinhole entry
after the firewall's configured idle traffic timeout.
3. Test Stream Transmission and Measurement Feedback Messages:
Testing proceeds with one endpoint sending Load PDUs and the
other endpoint receiving the Load PDUs and sending frequent
status messages to communicate status and transmission conditions
there. The data in the feedback messages, whether received from
the client or when being sent to the client, is input to a load
rate adjustment algorithm at the server which controls future
sending rates at either end. The choice to locate the load rate
adjustment algorithm at the server, regardless of transmission
direction, means that the algorithm can be updated more easily at
a host within the network, and at a fewer number of hosts than
the number of clients. Note, that this mode of operation also
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keeps the keep the pinhole (or mapping, resepcitvely) active at
on-path stateful devices. UDPSTP is at least partially compliant
to section 3.1 of [RFC8085]: the bottleneck is congested, but
pending congestion is avoided by limiting the duration of that
congestion to the minimum required to determine the bottleneck
capacity.
4. Stopping the Test: When the specified test duration has been
reached, the server initiates the exchange to stop the test by
setting a STOP indication in its outgoing Load PDUs or Status
Feedback messages. After being received, the client acknowledges
it by also setting a STOP indication in its outgoing Load PDUs or
Status Feedback messages. A graceful connection termination at
each end then follows. Since the Load PDUs and Status Feedback
messages are used, this exchange is considered a sub-exchange of
3. If the Test traffic stops or the communication path fails,
the client assumes that the firewall will close the address/port
number combination after the firewall's configured idle traffic
timeout.
5. Both the client and server react to unexpected interruptions in
the Control or Data phase, respectively. Watchdog timers limit
the time a server or client will wait before stopping all traffic
and terminating a test.
Figure 1 provides an example exchange of control and measurement PDUs
for both a downstream and upstream UDP Speed Tests (always client
initiated):
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=========== Downstream Test ===========
+---------+ +---------+
| Client | Test Setup Request -----> | Server |
+---------+ +---------+
<----- Test Setup Response (Accept)
<----- Null Request PDU
Test Activation Request ----->
<----- Test Activation Response (Accept)
<----- Load PDUs
Status Feedback PDUs ----->
After expiry of server's test duration timer...
<----- Load PDU (TEST_ACT_STOP)
Status Feedback PDU (TEST_ACT_STOP) ----->
============ Upstream Test ============
+---------+ +---------+
| Client | Test Setup Request -----> | Server |
+---------+ +---------+
<----- Test Setup Response (Accept)
<----- Null Request PDU
Test Activation Request ----->
<----- Test Activation Response (Accept)
Load PDUs ----->
<----- Status Feedback PDUs
After expiry of server's test duration timer...
<----- Status Feedback PDU (TEST_ACT_STOP)
Load PDU (TEST_ACT_STOP) ----->
Figure 1: Successful UDPSTP Message Exchanges
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4. Parameters, Security Operations, and Optional Checksum
Security and checksum operation aren't covered by [RFC9097], which
only defines the Method of Measurement. This section adds the
operational specification related to security and optional checksum.
Due to the additional complexities, and loss of the direct Layer 3 to
Layer 4 mapping of packets to datagrams, it is recommended that Layer
3 fragmentation be avoided. A simplified approach is to choose the
default datagram size small enough to prevent fragmentation. MTU
size detection prior to a test is out of scope of this document. A
method for a path MTU size discovery, as for example proposed by
[RFC8899], is left for future design and implementation.
4.1. Parameters and Definitions
Please refer to Section 4 of [RFC9097] for an overview of Parameters
related to the Maximum IP-Layer Capacity Metric and Method. A set of
error-codes to support debugging are provided in Section 11.2.5.
4.2. Security Mode Operations
There are four security modes of operation, one unauthenticated mode,
two authenticated modes and a fourth adding encryption. Operational
support of unauthenticated and authenticated modes MUST be mutually
exclusive. Once the modes requiring or optionally adding
authentication or encryption are implemented and configured locally,
the unauthenticated mode must be disabled. The four modes are:
1. An OPTIONAL Unauthenticated mode for all messages shall only be
allowed when all other modes requiring authentication (or Partial
Encryption) are unavailable for use. This mode is intended for a
lab or limited domain [RFC8799] hosting very low-end devices
lacking accurate clock synchronisation.
2. A REQUIRED mode with authentication during the Control phase
(Test Setup and Test Activation exchanges).
3. An OPTIONAL mode with the additional authentication of the Status
Feedback messages during the Data phase.
4. An OPTIONAL mode that adds encryption, prior to authentication,
of the Control phase exchanges and the Status Feedback messages.
This mode is optional, as Performance measurements don't
transport application data and encryption has impact on or at
least may impact performance measurements (especially on very
low-end devices).
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The requirements discussed hereafter refer to the PDUs in sections 5
and 6 below, primarily the authMode, keyId, authUnixTime, initVector,
and authDigest fields. The roles in this section have been
generalized so that the requirements for the PDU sender and receiver
can be re-used and referred to by other sections within this
document. Each successive mode increases security, but comes with
additional performance impacts and complexity. The protocol is used
with unsubstantial payload and it may operate on very low-end
devices. Offering the flexibility of various security operation
modes allows for adoption of available end-device resources. In
general, an active measurement technique as the one defined by this
document is better suited to protect the privacy of those involved in
measurement [RFC7594].
4.2.1. Mode 0: Optional Unauthenticated Mode
In this mode, all PDU senders SHALL set the keyId, authUnixTime, the
initVector, and the authDigest fields of all related packets to zero.
Any errors (configuration miss-match between client and server) found
in the Test Setup exchange or the Test Activation exchange SHOULD
result in silent rejection (no further packets sent on the address/
port pairs). The exception is when the testing hosts have been
configured for troubleshooting control phase failures and rejection
messages will aid in the process.
4.2.2. Mode 1: Required Authenticated Mode
In this mode, the client and the server SHALL be configured to use
one of a number of shared secret keys, designated via the numeric
keyId field (see Section 4.3).
During the Control phase, the sender SHALL read the current system
(wall-clock) time and populate the authUnixTime field and next
calculate the 32-octet HMAC-SHA256 hash of the entire PDU according
to section 6 of [RFC6234] (with initVector and authDigest preset to
all zeroes). The authDigest field is filled by the result, then the
packet is sent to the receiver. The value in the authUnixTime field
is a 32-bit time stamp and a 10-second tolerance window (+/- 5
seconds) SHALL be used by the receiver to distinguish a subsequent
replay of a PDU. See Table 2 of [TR-471] for a recommended timestamp
resolution. authUnixTime field, then calculate the of the entire
Status PDU (with the initVector and authDigest field set to all
zeroes), fill the authDigest field by the result and send the packet
to the receiver.
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Upon reception, the receiver SHALL validate the message PDU for
correct length, validity of authDigest, immediacy of authUnixTime,
and expected formatting (PDU-specific fields are also checked, such
as protocol version). Validation of the authDigest requires that it
will be extracted from the PDU and the field zeroed prior to the HMAC
calculation used for comparison (see section 7.2 of [RFC9145]).
If the validation fails, the receiver SHOULD NOT continue with the
Control phase and implement silent rejection (no further packets sent
on the address/port pairs). The exception is when the testing hosts
have been configured for troubleshooting Control phase failures and
rejection messages will aid in the process.
If the validation succeeds, the receiver SHALL continue with the
Control phase and compose a successful response or a response
indicating the error conditions identified (if any).
This process SHALL be executed for the request and response in the
Test Setup exchange, including the Null Request (Section 5) and the
Test Activation exchange (Section 6).
4.2.3. Mode 2: Optional Authenticated Mode for Data Phase
This mode incorporates Authenticated mode 1. When using the optional
authentication during the Data phase, authentication SHALL also be
applied to the Status Feedback PDU (see Section 7.2). The client
sends the Status PDU in a downstream test, and the server sends it in
an upstream test.
The Status PDU sender SHALL read the current system (wall-clock) time
and populate the authUnixTime field, then calculate the authDigest
field of the entire Status PDU (with the initVector and authDigest
field set to all zeroes) and send the packet to the receiver. The
values of authUnixTime field and authDigest field are determined as
defined by Section 4.2.2.
Upon reception, the receiver SHALL validate the message PDU for
correct length, validity of authDigest, immediacy of authUnixTime,
and expected formatting (PDU-specific fields are also checked, such
as protocol version). Validation of the authDigest will require that
it be extracted from the PDU and the field zeroed prior to the HMAC
calculation used for comparison.
If the authentication validation fails, the receiver SHALL ignore the
message. If the watchdog timer expires (due to successive failed
validations), the test session will prematurely terminate (no further
load traffic SHALL be transmitted).
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If this optional mode has not been selected, then the keyId,
authUnixTime, initVector, and authDigest fields of the Status PDU
(see Section 7.2) SHALL be set to all zeroes.
4.2.4. Mode 3: Optional Encryption of Control and Status
This mode incorporates authentication mode 2 after encryption of all
fields prior to the authMode field. This is done for all Control and
Status Feedback messages. The encryption algorithm only provides
encryption and relies on the existing authentication mechanism to
provide integrity protection. Adding encryption to prior
authentication allows to re-use code of optional authentication mode,
and additionally allows to re-use several protocol fields. Still,
both authentication and encryption are provided. See sections 5 to 7
for the field format.
When using the optional Encryption, the process SHALL be applied to
the Test Setup Request, the Test Setup Response, the Null Request (if
applicable), the Test Activation Request, the Test Activation
Response, and the Status PDU. The client sends the Status PDU in a
downstream test, and the server sends it in an upstream test.
In the OPTIONAL Encryption mode, the client and the server SHALL be
configured to use one of a number of shared secret keys (see keyId).
The following encryption specifications SHALL be used for this :
1. Advanced Encryption Standard, AES, according to Federal
Information Processing Standards Publication 197 [FIPS-197]
2. Cipher Block Chaining (CBC) [CBC]
3. Key size of 128 bits (fixed block size of 128 bits)
The encrypted portion of each PDU SHALL contain the padding required
to maintain a multiple of the AES CBC block size of 16 octets. As
such, any library functions used for encryption and decryption SHALL
have padding disabled (to maintain an equal encrypted and unencrypted
length). In OpenSSL for example, this can be accomplished via
"EVP_CIPHER_CTX_set_padding(ctx,0)".
The sender SHALL populate the initVector field with a
cryptographically random 16-octet Initialization Vector (IV), see
[RFC4086]. The IV, in conjunction with the shared secret key, SHALL
be used to encrypt the header up to, but not including, the authMode
field. The shared secret key is designated via the keyId field. The
sender SHALL then read the current system (wall-clock) time and
populate the authUnixTime field and then calculate (and populate) the
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authDigest, for the entire PDU, in the same manner as specified with
Authentication modes 1 and 2. Finally, the sender SHALL send the
packet with partially encrypted PDU to the receiver.
Upon reception, the receiver SHALL validate the message PDU for
correct length, validity of authDigest, and immediacy of
authUnixTime. Validation of the authDigest will require that it be
extracted from the PDU and the field zeroed prior to the HMAC
calculation used for comparison. If the PDU validation succeeds, the
receiver SHALL then decrypt the initial portion of the PDU using the
included IV and shared key designated by the keyId. Finally, the
PDU-specific fields that control the test are validated and
processed.
If the PDU validation fails in the Control phase, the receiver SHOULD
NOT continue with current exchange and implement silent rejection (no
further packets sent on the address/port pairs). The exception is
when the testing hosts have been configured for troubleshooting
Control phase failures and rejection messages will aid in the
process.
If the validation succeeds in the Control phase, the receiver SHALL
continue with the current exchange and compose a successful response
or a response indicating the error conditions identified. The
response PDU SHALL be encrypted and authenticated as described above
using a new random 16-octet IV. The packet with partially encrypted
PDU SHALL be sent back to the originator.
This process SHALL be executed for the request and response in the
Test Setup exchange, including the Null Request (Section 5) and the
Test Activation exchange (Section 6).
If the PDU validation fails for a Status PDU, the receiver SHALL
ignore the message. If the watchdog timer expires (due to successive
failed validations), the test session will prematurely terminate (no
further load traffic SHALL be transmitted).
4.3. Key Management
Section 2 of [RFC7210] specifies a conceptual database for long-lived
cryptographic keys. The key table SHALL be used with the REQUIRED
authentication mode and the OPTIONAL authentication mode (using the
same key). The same key table and key SHALL also be used with the
OPTIONAL Encryption mode, when utilized. The lifetime of the long-
lived keys deployed is expected be on the order of double digit
seconds to avoid pending congestion of the measured bottleneck. Key
rotation and related management specifics are beyond the scope of
this document.
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The key table SHALL have (at least) the following fields, referring
to Section 2 of [RFC7210]:
* AdminKeyName
* LocalKeyName
* AlgID
* Key
* SendLifetimeStart
* SendLifetimeEnd
* AcceptLifetimeStart
* AcceptLifetimeEnd
The LocalKeyName SHALL be determined from the corresponding keyId
field in the PDUs that follow.
4.4. Configuration of Network Functions with Stateful Filtering
Successful interaction with a local firewall assumes the firewall to
be configured allowing a host to open a bidirectional connection
using unique source and destination addresses as well as port numbers
by sending a packet using that 4-tuple for a given transport
protocol. The client's interaction with its firewall depends on this
configuration.
The firewall at the server MUST be configured with an open pinhole
for the server IP address and standard UDP port of the server. All
messages sent by the client to the server use this standard UDP port.
The server uses one ephemeral UDP port per test connection. Assuming
that the firewall administration at the server does not allow an open
UDP ephemeral port range, then the server MUST send a Null Request to
the client from the ephemeral port communicated to the client in the
Test Setup Response. The Null Request may not reach the client: it
may be discarded by the client's firewall.
If the server firewall administration allows an open UDP ephemeral
port range, then the Null Request is not strictly necessary.
However, the availability of an open port range policy cannot be
assumed.
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Network Address Translators (NATs) are expected to offer support of a
wider set of operational configurations as compared to Firewalls.
Specifications covering NAT behaviour apart from the above are out of
scope of this document, as are combined implementations of NAT and
Firewalls too.
4.5. Optional Checksum
All of the PDUs exchanged between the client and server support a
header checksum that covers the various fields in the UDPST PDU
(excluding the Payload Content of the Load PDU and, to be clear, also
the IP- and UDP-header). This checksum is intended for environments
where UDP data integrity may be uncertain. This includes situations
where the standard UDP checksum is disabled or a nonstandard network
API is in use (things typically done to improve performance on low-
end devices). The calculation is the same as the 16-bit one's
complement Internet checksum used in the IPv4 packet header (see
section 3.1 of [RFC0791]).
If a PDU sender is populating the checkSum field, it SHALL do so
after the PDU is built but prior to any authentication or encryption
processing (i.e., all fields starting with authMode are zeroed). The
PDU receiver SHALL subsequently verify the PDU checksum whenever
checksum processing has been configured. Verification requires that
all fields starting with authMode are zeroed prior to the checksum
calculation used to verify the PDU.
Because of its redundancy when authentication is being used, it is
OPTIONAL for a PDU sender to utilize the checkSum field whenever the
authDigest field is also utilized. However, because authentication
is not applicable to the Load PDU, the checkSum field SHALL be
utilized by the sender whenever UDP data integrity may be uncertain
(as outlined above).
5. Test Setup Request and Response
5.1. Client Generates Test Setup Request
The client SHALL begin the Control phase exchanges by sending a Test
Setup Request message to the server's (standard) control port. This
standard UDPSTP port number is utilized for each connection of a
multi-connection test (assuming each server to have a distinct IP
address and / or a client to have one or more distinct IP adresseses,
respectively).
The client SHALL simultaneously start a test initiation timer so that
if the Control phase fails to complete Test Setup and Test Activation
exchanges in the allocated time, the client software SHALL exit
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(close the UDP socket and indicate an error message to the user).
Lost messages result in a Test Setup and Test Activation failure.
The test initiation timer MAY reuse the test termination timeout
value.
The watchdog timeout is configured as a 1 second interval to trigger
a warning message that the received traffic has stopped. The test
termination timeout is based on the watchdog interval, and implements
a wait time of 2 additional seconds before triggering a non-graceful
termination.
The UDP PDU format layout SHALL be as follows (big-endian AB, most
significant to least significant byte):
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pduId | protocolVer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mcIndex | mcCount | mcIdent |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| cmdRequest | cmdResponse | maxBandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| testPort |modifierBitmap | reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| checkSum | reserved2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| padding (12 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authMode | keyId | reserved1a |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authUnixTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. initVector (16-octet) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. authDigest (32-octet) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Test Setup PDU Layout
Additional details regarding the Setup Request and Response fields
are as follows:
pduId: A two-octet field. IANA is asked to assign the value hex
0xACE1 (Section 11.2.1).
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protocolVer: A two-octet field, identifying the actual protocol
version. IANA is asked to assign only one initial value, 20
(Section 11.2.2).
mcIndex: The index of a connection relative to all connections that
make up a single test (starting at 0, incremented by 1 per
connection). It is used to differentiate separate connections within
a multi-connection test. An implementation may restrict the number
of connections supported for a single test to a value smaller or
equal to 255.
mcCount: The total count of attempted connections.
mcIdent: A pseudorandom non-zero identifier (via a Random Number
Generator, source port number,...) that is common to all connections
of a single test. It is used by clients/servers to associate
separate connections within a multi-connection test.
cmdRequest: Is set to CHSR_CREQ_SETUPREQ to indicate a Setup request
message. Note that CHSR_CREQ_NONE remains unused.
cmdResponse: All Request PDUs always have a Command Response of
XXXX_CRSP_NONE.
maxBandwith: When this field is non-zero, it is a specification of
the maximum bit rate the client expects to send or receive during the
requested test in Mbps. The server compares this value to its
currently available configured limit for test admission control.
This field MAY be used for rate-limiting the maximum rate the server
should attempt. The maxBandwidth field's most significant bit, the
CHSR_USDIR_BIT, is set to 0 by default to indicate "downstream" and
has to be set to 1 to indicate "upstream".
testPort: Set to zero in the Test Setup Request and populated by the
server in the Test Setup Response. It contains the UDP ephemeral
port number on the server that the client has to use for the Test
Activation Request and subsequent Load or Status PDUs.
modifierBitmap: this document only assigns two bits in this bitmap,
see Section 11.2.3:
CHSR_JUMBO_STATUS Above a sending rate of 1Gbps, allow datagram
sizes that result in Jumbo Frames (with a max IP packet size of
9000 bytes). Up to a sending rate of 1Gbps, or for all sending
rates if CHSR_JUMBO_STATUS is not set, datagram sizes SHALL NOT
produce an IP packet size greater than 1250 bytes (unless
CHSR_TRADITIONAL_MTU is also set).
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CHSR_TRADITIONAL_MTU Allow datagram sizes, at any sending rate, that
can result in a Traditional IP packet size of 1500 bytes.
Effectively increasing the default non-Jumbo maximum from 1250
bytes to 1500 bytes.
Other bit positions are left unassigned by this document.
checkSum: An optional checksum of the entire PDU (see Section 4.5 for
guidance). The calculation is done with the fields checksum,
authMode and those following after authMode set to zero.
authMode: The authMode field currently has four values assigned (see
Section 11.2.4). One of these has to be set (see Section 4.2 for
requirements and details of operation):
AUTHMODE_0: Optional Unauthenticated mode
AUTHMODE_1: Required Authentication for Control phase
AUTHMODE_2: Optional Authentication for Control and Data phase
(Status Feedback PDU only)
AUTHMODE_3: Optional Encrypted mode
A range of 60 through 63 is reserved for experimentation. A IANA is
asked to create a registry for the assigned values; see the IANA
Considerations Section.
keyId: This is a localKeyName, the numeric key identifier for a key
in the shared key table.
authUnixTime: A 32-bit time stamp of the current system (wall-clock)
time since the Unix Epoch on January 1st, 1970 at UTC.
initVector: This field contains the 16-octet random IV used for
Encryption mode. A new random 16-octet IV SHALL be used each time
encryption is performed.
authDigest: This field contains the 32-octet HMAC-SHA256 hash that
covers the entire PDU.
5.2. Server Test Setup Request Processing and Response Generation
This section describes the processes at the server to evaluate the
Test Setup Request and determine the next steps.
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5.2.1. Test Setup Request Processing - Rejection
When the server receives the Setup Request, it SHALL:
* verify the size of the Setup Request message and if correct
evaluate the authMode field,
* if operating in one of the Authenticated modes, validate the Setup
Request message by checking the authDigest as prescribed in
Section 4.2.2, and
* if operating in the Encryption mode, use the available keyId and
IV to decrypt the Setup Request message up to the authMode field
using the method prescribed in Section 4.2.4
Then, the server evaluates the other fields in the protocol header,
such as the protocol version, the PDU ID (to validate the type of
message), the maximum Bandwidth requested for the test, and the
modifierBitmap for use of options such as Jumbo datagram status and
Traditional MTU (1500 bytes).
If the client has selected options for:
* Jumbo datagram support (modifierBitmap),
* Traditional MTU (modifierBitmap),
* Authentication mode (authMode)
that do not match the server configuration, the server MUST reject
the Setup Request.
If the Setup Request must be rejected, the conditions below determine
whether the server sends a response:
* In Authenticated modes, if the authDigest is valid, a Test Setup
Response SHALL be sent back to the client with a corresponding
command response value indicating the reason for the rejection.
If operating in the Encryption mode, the server SHALL proceed per
Section 4.2.4, else the server SHALL proceed per Section 4.2.2.
* In Authenticated modes, if the authDigest is invalid, then the
Test Setup Request SHOULD fail silently. The exception is for
operations support: server administrators using authentication are
permitted to send a Setup Response to support operations and
troubleshooting.
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* If Unauthenticated mode is selected, the Test Setup Request SHALL
fail silently.
The additional, non-authentication circumstances when a server SHALL
NOT communicate the appropriate Command Response code for an error
condition (fail silently) are when:
1. the Setup Request PDU size is not equal to the 'struct
controlHdrSR' size shown in figure 3,
2. the PDU ID is not 0xACE1 (Test Setup PDU), or
3. a directed attack has been detected,
in which case the server will allow setup attempts to terminate
silently. Attack detection is beyond the scope of this
specification.
When the server replies to a Test Setup Request message, the Test
Setup Response PDU is structured identically to the Request PDU and
SHALL retain the original values received in it, with the following
exceptions:
* The cmdRequest field is set to CHSR_CREQ_SETUPRSP, indicating a
response.
* The cmdResponse field is set to an error code (starting at
cmdResponse 2, Bad Protocol Version, see Section 11.2.5),
indicating the reason for rejection. If cmdResponse indicates a
bad protocol version (CHSR_CRSP_BADVER), the protocolVer field is
also updated to indicate the current expected version.
* The PDU is encrypted up to the authMode field using a new random
IV, if doing encryption.
* The authUnixTime field is updated to the current system (wall-
clock) time and the authDigest is recalculated, if doing
authentication.
The Setup Request/Response message PDU SHALL be organized as follows:
<CODE BEGINS>
//
// Control header for UDP payload of Setup Request/Response PDUs
//
struct controlHdrSR {
#define CHSR_ID 0xACE1
uint16_t pduId; // PDU ID
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#define PROTOCOL_VER 20
uint16_t protocolVer; // Protocol version
uint8_t mcIndex; // Multi-connection index
uint8_t mcCount; // Multi-connection count
uint16_t mcIdent; // Multi-connection identifier
#define CHSR_CREQ_NONE 0
#define CHSR_CREQ_SETUPREQ 1 // Setup request
#define CHSR_CREQ_SETUPRSP 2 // Setup response
uint8_t cmdRequest; // Command request
#define CHSR_CRSP_NONE 0 // (used with request)
#define CHSR_CRSP_ACKOK 1 // Acknowledgment
#define CHSR_CRSP_BADVER 2 // Bad version
#define CHSR_CRSP_BADJS 3 // Jumbo setting mismatch
#define CHSR_CRSP_AUTHNC 4 // Auth. not configured
#define CHSR_CRSP_AUTHREQ 5 // Auth. required
#define CHSR_CRSP_AUTHINV 6 // Auth. (mode) invalid
#define CHSR_CRSP_AUTHFAIL 7 // Auth. failure
#define CHSR_CRSP_AUTHTIME 8 // Auth. time invalid
#define CHSR_CRSP_NOMAXBW 9 // Max bandwidth required
#define CHSR_CRSP_CAPEXC 10 // Capacity exceeded
#define CHSR_CRSP_BADTMTU 11 // Trad. MTU mismatch
#define CHSR_CRSP_MCINVPAR 12 // Multi-conn. invalid params
#define CHSR_CRSP_CONNFAIL 13 // Conn. allocation failure
uint8_t cmdResponse; // Command response
#define CHSR_USDIR_BIT 0x8000 // Upstream direction bit
uint16_t maxBandwidth; // Required bandwidth in Mbps
uint16_t testPort; // Test port on server
#define CHSR_JUMBO_STATUS 0x01
#define CHSR_TRADITIONAL_MTU 0x02
uint8_t modifierBitmap; // Modifier bitmap
uint8_t reserved1; // (reserved for alignment)
uint16_t checkSum; // Header checksum
uint16_t reserved2; // (reserved for alignment)
//
uint8_t padding[12]; // Padding for encryption
// ========== Encryption ends here ==========
#define AUTHMODE_0 0 // Mode 0: Unauthenticated
#define AUTHMODE_1 1 // Mode 1: Authenticated Control
#define AUTHMODE_2 2 // Mode 2: Authenticated Control+Status
#define AUTHMODE_3 3 // Mode 3: Encrypted+Auth Control+Status
uint8_t authMode; // Authentication mode
uint8_t keyId; // Key ID in shared table
uint16_t reserved1a; // (reserved for alignment)
uint32_t authUnixTime; // Authentication time stamp
#define AUTH_IV_LENGTH 16 // Initialization Vector length
uint8_t initVector[AUTH_IV_LENGTH] // IV
#define AUTH_DIGEST_LENGTH 32 // SHA-256 digest length
uint8_t authDigest[AUTH_DIGEST_LENGTH] // HMAC
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};
<CODE ENDS>
Figure 3: Test Setup PDU
5.2.2. Test Setup Request Processing - Acceptance
If the server finds that the Setup Request matches its configuration
and is otherwise acceptable, the server SHALL initiate a new
connection to receive the Test Activation Request from the client,
using a new UDP socket allocated from the UDP ephemeral port range.
This new socket will also be used for the subsequent Load and Status
PDUs that are part of testing (with the port number communicated back
to the client in testPort field of the Test Setup Response). Then,
the server SHALL start a watchdog timer (to terminate the new
connection if the client goes silent) and SHALL send the Test Setup
Response back to the client. The watchdog timer is set to the same
values as on the Client side (see Section 5)
When the server replies to the Test Setup Request message, the Test
Setup Response PDU is structured identically to the Request PDU and
SHALL retain the original values received in it, with the following
exceptions:
* The cmdRequest field is set to CHSR_CREQ_SETUPRSP, indicating a
response.
* The cmdResponse field is set to CHSR_CRSP_ACKOK, indicating an
acknowledgment.
* The testPort field is set to the ephemeral port number to be used
for the client's Test Activation Request and all subsequent
communication.
* The PDU is encrypted up to the authMode field using a new random
IV, if doing encryption.
* The authUnixTime field is updated to the current system (wall-
clock) time and the authDigest is recalculated, if doing
authentication.
Finally, the new UDP connection associated with the new socket and
port are made ready, and the server awaits further communication
there.
To ensure that a server's local firewall will successfully allow
packets received for the new ephemeral port, the server SHALL
immediately send a Null Request with the corresponding values
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including the source and destination IP addresses and port numbers.
The source port SHALL be the new ephemeral port. This operation
allows communication to the server even when the server's local
firewall prohibits open ranges of ephemeral ports. The packet is not
expected to arrive successfully at the client if the client-side
firewall blocks unexpected traffic. If the Null Request arrives at
the client, it is a confirmation that further exchanges are possible
on the new port-pair (but this is not strictly necessary). Note that
there is no response to a Null Request.
The UDP PDU format layout SHALL be as follows (big-endian AB):
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pduId | protocolVer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| cmdRequest | cmdResponse | checkSum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| padding (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authMode | keyId | reserved1a |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authUnixTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. initVector (16-octet) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. authDigest (32-octet) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Null Request PDU Layout
Additional details regarding the Null Request fields are as follows:
cmdRequest: Is set to CHNR_CREQ_NULLREQ indicating a Null Request
message.
pduId: A two-octet field. IANA is asked to assign the value hex
0xDEAD (Section 11.2.1).
cmdResponse: Is set to CHNR_CRSP_NONE.
checkSum: An optional checksum of the entire PDU (see Section 4.5 for
guidance). The calculation is done with the checkSum field, and all
fields starting with authMode, set to zero.
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If a Test Activation Request is not subsequently received from the
client on the new ephemeral port number before the watchdog timer
expires, the server SHALL close the socket and deallocate the
associated resources.
The Null Request message PDU SHALL be organized as follows:
<CODE BEGINS>
//
// Control header for UDP payload of Null Request PDU
//
struct controlHdrNR {
#define CHNR_ID 0xDEAD
uint16_t pduId; // PDU ID
uint16_t protocolVer; // Protocol version
#define CHNR_CREQ_NONE 0
#define CHNR_CREQ_NULLREQ 1 // Null request
uint8_t cmdRequest; // Command request
#define CHNR_CRSP_NONE 0 // (used with request)
uint8_t cmdResponse; // Command response
uint16_t checkSum; // Header checksum
//
uint8_t padding[8]; // Padding for encryption
// ========== Encryption ends here ==========
uint8_t authMode; // Authentication mode
uint8_t keyId; // Key ID in shared table
uint16_t reserved1a; // (reserved for alignment)
uint32_t authUnixTime; // Authentication time stamp
uint8_t initVector[AUTH_IV_LENGTH] // IV
uint8_t authDigest[AUTH_DIGEST_LENGTH] // HMAC
};
<CODE ENDS>
Figure 5: Null Request PDU
5.3. Setup Response Processing at the Client
When the client receives the Test Setup Response message, it SHALL:
* verify the size of the Setup Response message and if correct
interrogate the authMode field,
* if operating in one of the Authenticated modes, validate the Setup
Response message by checking the authDigest as prescribed in
Section 4.2.2,
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* if operating in the Encryption mode, use the available keyId and
IV to decrypt the Setup Response message up to the authMode using
the method prescribed in Section 4.2.4,
and then proceed to evaluate the other fields in the protocol,
beginning with the protocol version, PDU ID (to validate the type of
message), and cmdRequest for the role of the message, which MUST be
Test Setup Response, CHSR_CREQ_SETUPRSP, as indicated by figure 3.
If the cmdResponse value indicates an error (values greater than
CHSR_CRSP_ACKOK) the client SHALL display/report a relevant message
to the user or management process and exit. If the client receives a
Command Response code that is not equal to one of the codes defined,
the client MUST terminate the connection and terminate operation of
the current Setup Request. If the Command Server Response code value
indicates success (CHSR_CRSP_ACKOK), the client SHALL compose a Test
Activation Request with all the test parameters it desires, such as
the test direction, the test duration, etc., as described below.
6. Test Activation Request and Response
This section is divided according to the sending and processing of
the client, server, and again at the client.
6.1. Client Generates Test Activation Request
Upon a successful setup exchange, the client SHALL compose and send
the Test Activation Request to the UDP port number the server
communicated in the Test Setup Response (the new ephemeral port, and
not the standard UDPSTP port).
The UDP PDU format layout is as follows (big-endian AB):
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| txInterval1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| udpPayload1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| burstSize1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| txInterval2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| udpPayload2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| burstSize2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| udpAddon2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pduId | protocolVer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| cmdRequest | cmdResponse | lowThresh |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| upperThresh | trialInt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| testIntTime | subIntPeriod | ipTosByte |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| srIndexConf | useOwDelVar |highSpeedDelta |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| slowAdjThresh | seqErrThresh |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ignoreOooDup |modifierBitmap | rateAdjAlgo | reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. srStruct (28 octets) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| reserved2 | checkSum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| padding (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authMode | keyId | reserved1a |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authUnixTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. initVector (16-octet) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. authDigest (32-octet) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Test Activation PDU Layout
Fields are populated based on default values or command-line options.
Authentication and encryption modes follow the same methodology as
with the Setup Request and Response.
pduId: A two-octet field. IANA is asked to assign the value hex
0xACE2 (Section 11.2.1).
cmdRequest: Is set to CHTA_CREQ_TESTACTUS to indicate an upstream
test activation or alternatively to CHTA_CREQ_TESTACTDS to indicate a
downstream test activation. Note that CHTA_CREQ_NONE remains unused.
See Section 11.2.6
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The content of many of the unique fields in Figures 6 and 7 are
defined in Section 4 of [RFC9097] and Appendix A of [RFC9097].
Additional details are given below.
srIndexConf: The requested Configured Sending Rate Table index, used
in a Test Activation Request, of the desired fixed or starting
sending rate (depending on whether CHTA_SRIDX_ISSTART is cleared or
set respectively). Because a value of zero is a valid fixed or
starting sending rate index, the field SHALL be set to its maximum
(CHTA_SRIDX_DEF) when requesting the default behavior of the server
(starting the selected load rate adjustment algorithm at its minimum/
zero index). This SHALL be equivalent to setting srIndexConf to zero
and setting the CHTA_SRIDX_ISSTART bit.
rateAdjAlgo: The applied Load Rate Adjustment Algorithm, see
Section 11.2.8.
modifierBitmap: this document only assigns two bits in this bitmap,
see Section 11.2.7:
CHTA_SRIDX_ISSTART Treat srIndexConf as the starting sending rate to
be used by the load rate adjustment algorithm
CHTA_RAND_PAYLOAD Randomize the Payload Content beyond the Load PDU
header
Other bit positions are left unassigned by this document.
srStruct: Sending Rate structure, used by the server in a Test
Activation Response for an upstream test, to communicate the
(initial) Load PDU transmission parameters the client SHALL use. For
a Test Activation Request or a downstream test, this structure SHALL
be zeroed. Two sets of periodic transmission parameters are
available, allowing for dual independent transmitters (to support a
high degree of rate granularity). The udpAddon2 field specifies the
size of a single Load PDU to be sent at the end of the txInterval2
send sequence, even when udpPayload2 or burstSize2 are zero and
result in no transmission of their own.
checkSum: An optional checksum of the entire PDU (see Section 4.5 for
guidance). The calculation is done with the checkSum field, and all
fields starting with authMode, set to zero.
The Test Activation Request/Response message PDU (as well as the
included Sending Rate structure) SHALL be organized as follows:
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<CODE BEGINS>
//
// Sending rate structure for a single row of transmission parameters
//
struct sendingRate {
uint32_t txInterval1; // Transmit interval (us)
uint32_t udpPayload1; // UDP payload (bytes)
uint32_t burstSize1; // UDP burst size per interval
uint32_t txInterval2; // Transmit interval (us)
uint32_t udpPayload2; // UDP payload (bytes)
uint32_t burstSize2; // UDP burst size per interval
uint32_t udpAddon2; // UDP add-on (bytes)
};
//
// Control header for UDP payload of Test Act. Request/Response PDUs
//
struct controlHdrTA {
#define CHTA_ID 0xACE2
uint16_t pduId; // PDU ID
uint16_t protocolVer; // Protocol version
#define CHTA_CREQ_NONE 0
#define CHTA_CREQ_TESTACTUS 1 // Test activation upstream
#define CHTA_CREQ_TESTACTDS 2 // Test activation downstream
uint8_t cmdRequest; // Command request
#define CHTA_CRSP_NONE 0 // (used with request)
#define CHTA_CRSP_ACKOK 1 // Acknowledgment
#define CHTA_CRSP_BADPARAM 2 // Bad/invalid test params
uint8_t cmdResponse; // Command response
uint16_t lowThresh; // Low delay variation threshold (ms)
uint16_t upperThresh; // Upper delay variation threshold (ms)
uint16_t trialInt; // Status Feedback/trial interval (ms)
uint16_t testIntTime; // Test interval time (sec)
uint8_t subIntPeriod; // Sub-interval period (sec)
uint8_t ipTosByte; // IP ToS byte for testing
#define CHTA_SRIDX_DEF UINT16_MAX // Request default server rate search
uint16_t srIndexConf; // Configured Sending Rate Table index
uint8_t useOwDelVar; // Use one-way delay, not RTT (BOOL)
uint8_t highSpeedDelta; // High-speed row adjustment delta
uint16_t slowAdjThresh; // Slow rate adjustment threshold
uint16_t seqErrThresh; // Sequence error threshold
uint8_t ignoreOooDup; // Ignore Out-of-Order/Duplicates (BOOL)
#define CHTA_SRIDX_ISSTART 0x01 // Use srIndexConf as starting index
#define CHTA_RAND_PAYLOAD 0x02 // Randomize payload
uint8_t modifierBitmap; // Modifier bitmap
#define CHTA_RA_ALGO_B 0 // Algorithm B
#define CHTA_RA_ALGO_C 1 // Algorithm C
uint8_t rateAdjAlgo; // Rate adjust. algorithm
uint8_t reserved1; // (reserved for alignment)
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struct sendingRate srStruct; // Sending rate structure
uint16_t reserved2; // (reserved for alignment)
uint16_t checkSum; // Header checksum
//
uint8_t padding[4]; // Padding for encryption
// ========== Encryption ends here ==========
uint8_t authMode; // Authentication mode
uint8_t keyId; // Key ID in shared table
uint16_t reserved1a; // (reserved for alignment)
uint32_t authUnixTime; // Authentication time stamp
uint8_t initVector[AUTH_IV_LENGTH] // IV
uint8_t authDigest[AUTH_DIGEST_LENGTH] // HMAC
};
<CODE ENDS>
Figure 7: Test Activation PDU
6.2. Server Processes Test Activation Request and Generates Response
After the server receives the Test Activation Request on the new
connection, it MUST choose to accept, ignore or modify any of the
test parameters. When the server replies to the Test Activation
Request message, the Test Activation Response PDU is structured
identically to the Request PDU and SHALL retain the original values
received in it unless they are explicitly coerced to a server
acceptable value.
6.2.1. Server Rejects or Modifies Request
When evaluating the Test Activation Request, the server MAY allow the
client to specify its own fixed or starting send rate via
srIndexConf.
Alternatively, the server MAY enforce a maximum limit of the fixed or
starting send rate which the client can successfully request. If the
client's Test Activation Request exceeds the server's configured
maximum, the server MUST either reject the request or coerce the
value to the configured maximum bit rate, and communicate that
maximum to the client in the Test Activation Response. The client
can of course choose to end the test, as appropriate.
Other parameters where the server has the OPTION to coerce the client
to use values other than those in the Test Activation Request are
(grouped by role):
* Load rate adjustment algorithm: lowThresh, upperThresh,
useOwDelayVar, highSpeedDelta, slowAdjThresh, seqErrThresh,
highSpeedDelta, ignoreOooDup, rateAdjAlgo.
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* Test duration/intervals: trialInt, testIntTime, subIntPeriod
* Packet marking: ipTosByte
Coercion is a step towards performing a test with the server-
configured values; even though the client might prefer certain
values, the server gives the client an opportunity to run a test with
different values than the preferred set. In these cases, the Command
Response value SHALL be CHTA_CRSP_ACKOK.
Note that the server also has the option of completely rejecting the
request and sending back an appropriate cmdResponse field value
(currently only CHTA_CRSP_BADPARAM, see Section 11.2.9).
Whether this error response is sent or not depends on the Security
mode of operation and the outcome of authDigest validation.
If the Test Activation Request must be rejected (due to the Command
Response value being CHTA_CRSP_BADPARAM), and
* In Authenticated modes, if the authDigest is valid, a Test
Activation Response SHALL be sent back to the client with a
corresponding command response value indicating the reason for the
rejection. If operating in the Encryption mode, the server SHALL
follow the requirements of Section 4.2.4, else the server SHALL
follow the requirements of Section 4.2.2.
* In Authenticated modes, if the authDigest is invalid, then the
Test Activation Request SHOULD fail silently. The exception is
for operations support: server administrators using Authentication
are permitted to send a Setup Response to support operations and
troubleshooting.
* If Unauthenticated mode is selected, the Test Activation Request
SHALL fail silently.
The additional, non-authentication circumstances when a server SHALL
NOT communicate the appropriate Command Response code for an error
condition (fail silently) are when:
1. the Test Activation Request PDU size is not equal to the 'struct
controlHdrTA' size shown in figure 7,
2. the PDU ID is not 0xACE2 (Test Activation PDU), or
3. a directed attack has been detected,
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in which case the server will allow Test Activation Requests to
terminate silently. Attack detection is beyond the scope of this
specification.
6.2.2. Server Accepts Request and Generates Response
When the server sends the Test Activation Response, it SHALL set the
cmdResponse field to CHTA_CRSP_ACKOK (see Section 11.2.9)
If the client has requested an upstream test, the server SHALL:
* include the transmission parameters from the first row of the
Sending Rate Table in the Sending Rate structure (if requested by
srIndexConf having been set to CHTA_SRIDX_DEF), or
* include the transmission parameters from the designated Configured
Sending Rate Table index (srIndexConf) of the Sending Rate
Table where, if CHTA_SRIDX_ISSTART is set in modifierBitmap, this
will be used as the starting rate for the load rate adjustment
algorithm, else it will be considered a fixed rate test.
When generating the Test Activation Response (acceptance) for a
downstream test, the server SHALL set all octets of the Sending Rate
structure to zero.
If activation continues, the server prepares the new connection for
an upstream OR downstream test.
In the case of an upstream test, the server SHALL prepare to use a
single timer to send Status PDUs at the specified interval. For a
downstream test, the server SHALL prepare to utilize dual timers to
send Load PDUs based on
* the transmission parameters directly from the first row of the
Sending Rate Table (if requested by srIndexConf having been set to
CHTA_SRIDX_DEF), or
* the transmission parameters from the designated Configured Sending
Rate Table index (srIndexConf) of the Sending Rate Table where, if
CHTA_SRIDX_ISSTART is set in modifierBitmap, this will be used as
the starting rate for the load rate adjustment algorithm, else it
will be considered a fixed rate test.
The server SHALL then send the Test Activation Response back to the
client, update the watchdog timer with a new timeout value, and set a
test duration timer to eventually stop the test.
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6.3. Client Processes Test Activation Response
When the client receives the Test Activation Response, it SHALL:
* If operating in an Authenticated mode, check the message PDU for
validity via the authDigest field and acceptable immediacy via the
authUnixTime field. If validated, and if operating in Partial
Encryption mode, decrypt the PDU using the included IV and shared
key designated via keyId. Finally, check the PDU for general
formatting, such as protocol version, and any PDU-specific fields
that control the test.
When the client receives the (vetted) Test Activation Response, it
first checks the command response value.
If the client receives a Test Activation cmdResponse field value that
indicates an error, the client SHALL display/report a relevant
message to the user or management process and exit.
If the client receives a Test Activation cmdResponse field value that
is not equal to one of the codes defined in Section 11.2.9, the
client MUST terminate the connection and terminate operation of the
current setup procedure.
If the client receives a Test Activation Command Response value that
indicates success (CHTA_CRSP_ACKOK, see Section 11.2.9), the client
SHALL update its configuration to use any test parameters modified by
the server.
Next, the client SHALL prepare its connection for either an upstream
test with dual timers set to send Load PDUs (based on the starting
transmission parameters sent by the server), OR a downstream test
with a single timer to send Status PDUs at the specified interval.
Then, the client SHALL stop the test initiation timer and start a
watchdog timer to detect if the server goes quiet.
The connection is now ready for testing.
7. Test Stream Transmission and Measurement Feedback Messages
This section describes the data phase of the protocol. The roles of
sender and receiver vary depending whether the direction of testing
is from server to client, or the reverse.
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7.1. Test Packet PDU and Roles
Testing proceeds with one endpoint sending Load PDUs, based on
transmission parameters from the Sending Rate Table, and the other
endpoint sending Status Feedback messages to communicate the traffic
conditions at the receiver. When the server is sending Status
Feedback messages, they will also contain the latest transmission
parameters from the Sending Rate Table that the client SHALL use.
The watchdog timer at the receiver SHALL be reset each time a PDU is
received. See non-graceful test stop in Section 8 for handling the
watchdog timeout expiration at each endpoint.
When the server is sending Load PDUs in the role of sender, it SHALL
use the transmission parameters directly from the Sending Rate
Table via the index that is currently selected (which was indirectly
based on the feedback in its received Status Feedback messages).
However, when the client is sending Load PDUs in the role of sender,
it SHALL use the discreet transmission parameters that were
communicated by the server in its periodic Status Feedback messages
(and not referencing a Sending Rate Table directly). This approach
allows the server to control the individual sending rates as well as
the algorithm used to decide when and how to adjust the rate.
The server uses a load rate adjustment algorithm which evaluates
measurements taken locally at the Load PDU receiver. When the client
is the receiver, the information is communicated to the server via
the periodic Status Feedback messages. When the server is the
receiver, the information is used directly (although it is also
communicated to the client via its periodic Status Feedback
messages). This approach is unique to this protocol; it provides the
ability to search for the Maximum IP Capacity and specify specific
sender behaviors that is absent from other testing tools. Although
the algorithm depends on the protocol, it is not part of the protocol
per se.
The default algorithm (B, see [Y.1540]) has three paths to its
decision on the next sending rate:
1. When there are no impairments present (no sequence errors and low
delay variation), resulting in a sending rate increase.
2. When there are low impairments present (no sequence errors but
higher levels of delay variation), the same sending rate is
maintained.
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3. When the impairment levels are above the thresholds set for this
purpose and "congestion" is inferred, resulting in a sending rate
decrease.
Algorithm B also has two modes for increasing/decreasing the sending
rate:
* A high-speed mode (fast) to achieve high sending rates quickly,
but also back-off quickly when "congestion" is inferred from the
measurements. Consecutive feedback intervals that have a supra-
threshold count of sequence number anomalies and/or contain an
upper delay variation threshold exception in all of the
consecutive intervals are sufficient to declare "congestion"
within a test. The threshold of consecutive feedback intervals
SHALL be configurable with a default of 3 intervals.
* A single-step (slow) mode where all rate adjustments use the
minimum increase or decrease of one step in the sending rate
table. The single step mode continues after the first inference
of "congestion" from measured impairments.
An OPTIONAL load rate adjustment algorithm (designated C) has been
defined in [TR-471]. Algorithm C operation and modes are similar to
B, but C uses multiplicative increases in the fast mode to reach the
Gigabit range quickly and adds the possibility to re-try the fast
mode during a test (which improves the measurement accuracy in
dynamic or error-prone access, such as radio access).
On the other hand, the test configuration MAY use a fixed sending
rate requested by the client, using the field srIndexConf.
The client MAY communicate the desired fixed rate in its test
activation request. The reasons to conduct a fixed-rate test include
stable measurement at the maximum determined by the load rate
adjustment algorithm, or the desire to test at a known subscribed
rate without searching.
The UDP PDU format layout SHALL be as follows (big-endian AB):
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pduId | testAction | rxStopped |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lpduSeqNo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| udpPayload | spduSeqErr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduTime_sec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduTime_nsec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lpduTime_sec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lpduTime_nsec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttRespDelay | checkSum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. Payload Content... .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Load PDU Layout
Specific details regarding Load PDU fields are as follows:
pduId: A two-octet field. IANA is asked to assign the value hex
0xBEEF (Section 11.2.1).
testAction: Designates the current test action as either
TEST_ACT_TEST (testing in progress), TEST_ACT_STOP1 (first phase of
graceful termination, used locally by server), or TEST_ACT_STOP2
(second phase of graceful termination, sent by server and
reciprocated by client). See Section 8 for additional information on
test termination.
rxStopped: A boolean (0 or 1) used to indicate to the remote endpoint
that local receive traffic (either Load or Status PDUs) has stopped.
All outgoing Load or Status PDUs SHALL continue to assert this
indication until traffic is received again, or the test is
terminated. The time threshold to trigger this condition is expected
to be a reasonable fraction of the watchdog timeout (a default of one
second is recommended).
lpduSeqNo: Load PDU sequence number (starting at 1). Used to
determine loss, out-of-order, and duplicates.
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udpPayload: The total payload size of the UDP datagram including the
Load PDU message header and Payload Content (i.e., what the UDP
socket read function would return). This field allows the Load PDU
receiver to maintain accurate receive statistics if utilizing receive
truncation (only requesting the Load PDU message header octets from
the protocol stack).
spduSeqErr: Status PDU loss count, as seen by the Load PDU sender.
This is determined by the Status PDU sequence number (spduSeqNo) in
the most recently received Status PDU. Used to communicate to the
Load PDU receiver that return traffic (in the unloaded direction) is
being lost.
spduTime_sec/spduTime_nsec: A copy of the most recent spduTime_sec/
spduTime_nsec from the last Status PDU received. Used for RTT
measurements made by the Load PDU receiver.
lpduTime_sec/lpduTime_nsec: The local send time of the Load PDU.
Used for one-way delay variation measurements made by the Load PDU
receiver.
rttRespDelay: RTT response delay, used to "adjust" raw RTT. On the
Load PDU sender, it is the number of milliseconds from reception of
the most recent Status PDU (when the latest spduTime_sec/
spduTime_nsec was obtained) to the transmission of the Load PDU
(where the previously obtained spduTime_sec/spduTime_nsec is
returned). When the Load PDU receiver is calculating RTT, by
subtracting the copied Status PDU send time (in the Load PDU) from
the local Load PDU receive time, this value is subtracted from the
raw RTT to correct for any response delay due to Load PDU scheduling.
checkSum: An optional checksum of only the Load PDU header (see
Section 4.5 for guidance). The checksum does not cover the Payload
Content. The calculation is done with the checkSum field set to
zero.
Payload Content: All zeroes, all ones, or a pseudorandom binary
sequence.
The Load PDU SHALL be organized as follows (followed by any payload
content):
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<CODE BEGINS>
//
// Load header for UDP payload of Load PDUs
//
struct loadHdr {
#define LOAD_ID 0xBEEF
uint16_t pduId; // PDU ID
#define TEST_ACT_TEST 0 // Test active
#define TEST_ACT_STOP1 1 // Stop indication used locally by server
#define TEST_ACT_STOP2 2 // Stop indication exchanged with client
uint8_t testAction; // Test action
uint8_t rxStopped; // Receive traffic stopped indicator (BOOL)
uint32_t lpduSeqNo; // Load PDU sequence number
uint16_t udpPayload; // UDP payload (bytes)
uint16_t spduSeqErr; // Status PDU sequence error count
uint32_t spduTime_sec; // Send time in last received status PDU
uint32_t spduTime_nsec; // Send time in last received status PDU
uint32_t lpduTime_sec; // Send time of this load PDU
uint32_t lpduTime_nsec; // Send time of this load PDU
uint16_t rttRespDelay; // Response delay for RTT (ms)
uint16_t checkSum; // Header checksum
};
<CODE ENDS>
Figure 9: Load PDU
7.2. Status PDU
The Load PDU receiver SHALL send a Status PDU to the sender during a
test at the configured feedback interval, after at least one Load PDU
has been received (when there is something to provide status on). In
test scenarios with long delays between client and server, it is
possible for the Status PDU send timer to fire before the first Load
PDU arrives. In these cases, the Status PDU SHALL NOT be sent.
The watchdog timer at the Load PDU sender SHALL be reset each time a
Status PDU is received. See non-graceful test stop in Section 8 for
handling the watchdog timeout expiration at each endpoint.
The UDP PDU format layout SHALL be as follows (big-endian AB):
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rxDatagrams |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rxBytes |
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| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| deltaTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrLoss |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrOoo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrDup |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarMin |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarMax |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarSum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarCnt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttVarMinimum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttVarMaximum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| accumTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pduId | testAction | rxStopped |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduSeqNo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. srStruct (28 octets) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| subIntSeqNo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. sisSav (56 octets) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrLoss |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrOoo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrDup |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| clockDeltaMin |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarMin |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| delayVarMax |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarSum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarCnt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttMinimum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttVarSample |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayMinUpd | reserved1 | checkSum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| tiDeltaTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| tiRxDatagrams |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| tiRxBytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduTime_sec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduTime_nsec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authMode | keyId | reserved1a |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authUnixTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. initVector (16-octet) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. authDigest (32-octet) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Status PDU Layout
Note that the Sending Rate structure is defined in Section 6.
The primary role of the Status Feedback message is to communicate to
the Load PDU sender the traffic conditions at the Load PDU receiver.
While the Sub-Interval Statistics structure (sisSav) covers the most
recently saved (completed) sub-interval, similar fields directly in
the Status PDU itself cover the most recent trial interval (the time
period between Status Feedback messages, completed by this Status
PDU). Both sets of statistics SHALL always be populated by the Load
PDU receiver, regardless of role (client or server).
Details on the Status PDU measurement fields are provided in
[RFC9097]. Additional information regarding fields not defined
previously are as follows:
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pduId: A two-octet field. IANA is asked to assign the value hex
0xFEED (Section 11.2.1).
rxDatagrams/rxBytes/deltaTime: Sub-interval received datagram and
byte counts as well as the exact duration of the sub-interval in
microseconds. Used to calculate the received traffic rate for the
sub-interval. The rxBytes field is a 64-bit value to prevent
overflow at high speeds.
seqErrLoss/seqErrOoo/seqErrDup: Loss, out-of-order, and duplicate
totals. Available for both the sub-interval and trial interval.
seqErrOoo and seqErrDup are realized by comparing sequence numbers.
A lookback list of the last n sequence numbers received is used as
the basis. Each Load PDU sequence number is checked against this
lookback. The number n may depend on the implementation and on
typical characteristics of environments, where UDPST is deployed
(like mobile networks or Wi-Fi). Currently, a default sequence
number interval of n=32 has been chosen. Specifically for seqErrOoo,
each successively received higher seqno sets the next-expected-seqno
to seqno+1 and anything below that is considered out-of-order (i.e.,
delayed). For example, given the sequence 93, 94, 95, 100, 96, 97,
101, 98, 99, 102, 103, ... reception of 96, 97, 98, and 99 would not
increment the next-expected-seqno and would all be considered out-of-
order.
delayVarMin/delayVarMax/delayVarSum/delayVarCnt: The one-way delay
variation measurements of all received Load PDUs (where avg = sum/
cnt). For each Load PDU received, the send time (lpduTime_sec/
lpduTime_nsec) is subtracted from the local receive time, which is
then normalized by subtracting the current clockDeltaMin. Available
for both the sub-interval and trial interval.
rttVarMinimum/rttVarMaximum (in sisSav): The minimum and maximum RTT
delay variation (rttVarSample) in the sub-interval designated by the
subIntSeqNo.
accumTime: The accumulated time of the test in milliseconds, based on
the duration of each sub-interval. Equivalent to the sum of each
deltaTime (although in ms) sent in each Status PDU during the test.
spduSeqNo: Status PDU sequence number (starting at 1). Used by the
Load PDU sender to detect Status PDU loss (in the unloaded
direction). The loss count is communicated back to the Load PDU
receiver via spduSeqErr in subsequent Load PDUs.
subIntSeqNo: Sub-interval sequence number (starting at 1) that
corresponds to the statistics provided in sisSav, for the last saved
(completed) sub-interval.
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sisSav: Sub-interval statistics saved (completed) for the most recent
sub-interval (as designated by the subIntSeqNo).
clockDeltaMin: The minimum clock delta (difference) since the
beginning of the test. Obtained by subtracting the send time of each
Load PDU (lpduTime_sec/lpduTime_nsec) from the local time that it was
received. This value is initialized with the first Load PDU received
and is updated with each subsequent one to maintain a current (and
continuously updated) minimum. If the endpoint clocks are
sufficiently synchronized, this will be the minimum one-way delay in
milliseconds. Otherwise, this value may be negative, but still valid
for one-way delay variation measurements for the default test
duration (default is 10 [s]). If the test duration is extended to a
range of minutes, where significant clock drift can occur,
synchronized (or at least well disciplined) clocks may be required.
rttMinimum (in Status PDU): The minimum "adjusted" RTT measured since
the beginning of the test. See rttRespDelay regarding "adjusted"
measurements. RTT is obtained by subtracting the copied
spduTime_sec/spduTime_nsec in the received Load PDU from the local
time at which it was received. This minimum SHALL be kept current
(and continuously updated) via each Load PDU received with an updated
spduTime_sec/spduTime_nsec. This value MUST be positive. Before an
initial value can be established, and because zero is itself valid,
it SHALL be set to STATUS_NORTT when communicated in the Status PDU.
rttVarSample: The most recent "adjusted" RTT delay variation
measurement. See rttRespDelay regarding "adjusted" measurements.
RTT delay variation is obtained by subtracting the current (and
continuously updated) "adjusted" RTT minimum, communicated as
rttMinimum (in Status PDU), from each "adjusted" RTT measurement
(which is itself obtained by subtracting the copied spduTime_sec/
spduTime_nsec in the received Load PDU from the local time at which
it was received). Note that while one-way delay variation is
measured for every Load PDU received, RTT delay variation is only
sampled via the Status PDU sent and the very next Load PDU received
with the corresponding updated spduTime_sec/spduTime_nsec. When a
new value is unavailable (possibly due to packet loss), and because
zero is itself valid, it SHALL be set to STATUS_NORTT when
communicated in the Status PDU.
delayMinUpd: Boolean (0 or 1) indicating that the clockDeltaMin and/
or rttMinimum (in Status PDU), as measured by the Load PDU receiver,
has been updated.
checkSum: An optional checksum of the entire PDU (see Section 4.5 for
guidance). The calculation is done with the checkSum field, and all
fields starting with authMode, set to zero.
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tiDeltaTime/tiRxDatagrams/tiRxBytes: The trial interval time in
microseconds, along with the received datagram and byte counts. Used
to calculate the received traffic rate for the trial interval.
spduTime_sec/spduTime_nsec: The local transmit time of the Status
PDU. Expected to be copied into spduTime_sec/spduTime_nsec in
subsequent Load PDUs after being received by the Load PDU sender.
Used for RTT measurements.
The authentication, encryption, and checksum fields and their
operation are as defined previously in Section 4.
The Status Feedback message PDU (as well as the included Sub-Interval
Statistics structure) SHALL be organized as follows:
<CODE BEGINS>
//
// Sub-interval statistics structure for received traffic information
//
struct subIntStats {
uint32_t rxDatagrams; // Received datagrams
uint64_t rxBytes; // Received bytes (64 bits)
uint32_t deltaTime; // Time delta (us)
uint32_t seqErrLoss; // Loss sum
uint32_t seqErrOoo; // Out-of-Order sum
uint32_t seqErrDup; // Duplicate sum
uint32_t delayVarMin; // Delay variation minimum (ms)
uint32_t delayVarMax; // Delay variation maximum (ms)
uint32_t delayVarSum; // Delay variation sum (ms)
uint32_t delayVarCnt; // Delay variation count
uint32_t rttMinimum; // Minimum round-trip time (ms)
uint32_t rttMaximum; // Maximum round-trip time (ms)
uint32_t accumTime; // Accumulated time (ms)
};
//
// Status feedback header for UDP payload of status PDUs
//
struct statusHdr {
#define STATUS_ID 0xFEED
uint16_t pduId; // PDU ID
uint8_t testAction; // Test action
uint8_t rxStopped; // Receive traffic stopped indicator (BOOL)
uint32_t spduSeqNo; // Status PDU sequence number
struct sendingRate srStruct; // Sending rate structure
uint32_t subIntSeqNo; // Sub-interval sequence number
struct subIntStats sisSav; // Sub-interval saved stats
uint32_t seqErrLoss; // Loss sum
uint32_t seqErrOoo; // Out-of-Order sum
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uint32_t seqErrDup; // Duplicate sum
uint32_t clockDeltaMin; // Clock delta minimum (ms)
uint32_t delayVarMin; // Delay variation minimum (ms)
uint32_t delayVarMax; // Delay variation maximum (ms)
uint32_t delayVarSum; // Delay variation sum (ms)
uint32_t delayVarCnt; // Delay variation count
#define STATUS_NORTT UINT32_MAX // No RTT data/value
uint32_t rttMinimum; // Minimum round-trip time sampled (ms)
uint32_t rttVarSample; // Last round-trip time sample (ms)
uint8_t delayMinUpd; // Delay minimum(s) updated (BOOL)
uint8_t reserved1; // (reserved for alignment)
uint16_t checkSum; // Header checksum
uint32_t tiDeltaTime; // Trial interval delta time (us)
uint32_t tiRxDatagrams; // Trial interval receive datagrams
uint32_t tiRxBytes; // Trial interval receive bytes
uint32_t spduTime_sec; // Send time of this status PDU
uint32_t spduTime_nsec; // Send time of this status PDU
//
// ========== Encryption ends here ==========
uint8_t authMode; // Authentication mode
uint8_t keyId; // Key ID in shared table
uint16_t reserved1a; // (reserved for alignment)
uint32_t authUnixTime; // Authentication time stamp
uint8_t initVector[AUTH_IV_LENGTH] // IV
uint8_t authDigest[AUTH_DIGEST_LENGTH] // HMAC
};
<CODE ENDS>
Figure 11: Status PDU
8. Stopping a Test
When the test duration timer (testIntTime) on the server expires, it
SHALL set the local connection test action to TEST_ACT_STOP1 (phase 1
of graceful termination). This is simply a non-reversible state
awaiting the next message(s) to be sent from the server. During this
time, any received Load or Status PDUs are processed normally.
Upon transmission of the next Load or Status PDUs, the server SHALL
set the local connection test action to TEST_ACT_STOP2 (phase 2 of
graceful termination) and mark any outgoing PDUs with a testAction
value of TEST_ACT_STOP2. While in this state, the server MAY reduce
any Load PDU bursts to a size of one.
When the client receives a Load or Status PDU with the TEST_ACT_STOP2
indication, it SHALL finalize testing, display the test results, and
also mark its local connection with a test action of TEST_ACT_STOP2
(so that any PDUs subsequently received can be ignored).
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With the test action of the client's connection set to
TEST_ACT_STOP2, the very next expiry of a send timer, for either a
Load or Status PDU, SHALL result in it and any subsequent PDUs to be
sent with a testAction value of TEST_ACT_STOP2 (as confirmation to
the server). While in this state, the client MAY reduce any Load PDU
bursts to a size of one. The client SHALL then schedule an immediate
end time for the connection.
When the server receives the TEST_ACT_STOP2 confirmation in the Load
or Status PDU, the server SHALL schedule an immediate end time for
the connection which closes the socket and deallocates the associated
resources. The TEST_ACT_STOP2 exchange constitutes a graceful
termination of the test.
In a non-graceful test stop due to path failure, the watchdog
timeouts at each endpoint will expire (sometimes at one endpoint
first), notifications in logs, STDOUT, and/or formatted output SHALL
be made, and the endpoint SHALL schedule an immediate end time for
the connection.
If an attacker clears the TEST_ACT_STOP2 indication, then the
configured test duration timer (testIntTime) at the server and client
SHALL take precedence and the endpoint SHALL schedule an immediate
end time for the connection.
9. Method of Measurement
The architecture of the method requires two cooperating hosts
operating in the roles of Src (test packet sender) and Dst
(receiver), with a measured path and return path between them.
The duration of a test, parameter I, MUST be constrained in a
production network, since this is an active test method and it will
likely cause congestion on the Src to Dst host path during a test.
9.1. Notes on Interface Measurements
Additional measurements may be useful in specific circumstances. For
example, interface byte counters measured by a client at a
residential gateway are possible when the client application has
access to an interface that sees all traffic to/from a service
subscriber's location. Adding a byte counter at the client for
download or upload directions could be used to measure total traffic
and possibly detect when non-test traffic is present (and using
capacity). The client may not have the CPU cycles available to count
both the interface traffic and IP-layer Capacity simultaneously, so
this form of diagnostic measurement may not be possible.
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10. Security Considerations
Active metrics and measurements have a long history of security
considerations. The security considerations that apply to any active
measurement of live paths are relevant here. See [RFC4656] and
[RFC5357].
When considering privacy of those involved in measurement or those
whose traffic is measured, the sensitive information available to
potential observers is greatly reduced when using active techniques
which are within this scope of work. Passive observations of user
traffic for measurement purposes raise many privacy issues. We refer
the reader to the privacy considerations described in the Large Scale
Measurement of Broadband Performance (LMAP) Framework [RFC7594],
which covers active and passive techniques.
There are some new considerations for Capacity measurement as
described in this document.
1. Cooperating client and server hosts and agreements to test the
path between the hosts are REQUIRED. Hosts perform in either the
server or client roles. One way to assure a cooperative
agreement employs the optional Authorization mode through the use
of the authDigest field and the known identity associated with
the key used to create the authDigest field. Other means are
also possible, such as access control lists at the server.
2. It is REQUIRED to have a user client-initiated setup handshake
between cooperating hosts that allows firewalls to control
inbound unsolicited UDP traffic which either goes to a control
port or to ephemeral ports that are only created as needed.
Firewalls protecting each host can both continue to do their job
normally.
3. Client-server authentication and integrity protection for
feedback messages conveying measurements is RECOMMENDED. To
accommodate different host limitations and testing circumstances,
different modes of operation are available, as described in
Section 4 above.
4. Hosts MUST limit the number of simultaneous tests to avoid
resource exhaustion and inaccurate results.
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5. Senders MUST be rate-limited. This can be accomplished using a
pre-built table defining all the offered sending rates that will
be supported. The default and optional load rate adjustment
algorithm results in "ramp up" from the lowest rate in the table.
Optionally, the server could utilize the maxBandwidth field (and
CHSR_USDIR_BIT bit) in the Setup Request from the client to limit
the maximum that it will attempt to achieve.
6. Service subscribers with limited data volumes who conduct
extensive capacity testing might experience the effects of
Service Provider controls on their service. Testing with the
Service Provider's measurement hosts SHOULD be limited in
frequency and/or overall volume of test traffic (for example, the
range of test interval duration values should be limited).
One specific attack that has been recognized is an on-path attack on
the testAction field where the attacker would set or clear the STOP
indication. Setting the indication in successive packets terminates
the test prematurely, with no threat to the Internet but annoyance
for the testers. If an attacker clears the STOP indication, the
mitigation relies on knowledge of the test duration at the client and
server, where these hosts cease all traffic when the specified test
duration is complete.
Authentication and encryption methods and requirements steadily
evolve. Alternate encryption and/or authentication modes provide for
algorithm agility by defining a new Mode, whose support is indicated
by an assigning a suitable "Test Setup PDU Authentication Mode
Registry" value (see Section 11.2.4 ).
11. IANA Considerations
This document requests IANA to assign a User/Registered UDP port for
the Test Setup exchange in the Control phase of protocol operation,
and to create a new registry group for the UDP Speed Test Protocol
(UDPSTP).
11.1. New System Port Number Assignment
IANA will allocate the following service name to the "Service Name
and Transport Protocol Port Number Registry" registry:
Service: udpst-control
Transport Protocol: UDP
Assignee: IESG <iesg@ietf.org>
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Contact: IETF Chair <chair@ietf.org>
Description: UDP-based IP-Layer Capacity and performance measurement
protocol
Reference: This RFC, RFCYYYY. The protocol uses IP-Layer Unicast.
The assignment of a single port number is requested to help
configuring firewalls and other port-based systems for access
control prior to negotiating dynamic ports between client and
server.
Port Number: <PORTNUM> of the IANA User Port range (1024-49151)
11.2. New UDPSTP Registry Group
IANA will create the following registry in a new registry group
called "UDP Speed Test Protocol (UDPSTP)":
Registration Procedure: see below
Reference: <This RFC>
Experts: <To be set at publication>
11.2.1. PDU Identifier Registry
IANA will create the "PDU Identifier" registry under the "UDP Speed
Test Protocol (UDPSTP)" registry group. Every UDPSTP PDU contains a
two octet pduId field identifying the role and format of the PDU that
follows. The code points in this registry are allocated according to
the registration procedures [RFC8126] described in Table 1.
Range(Hex) Registration Procedures
===============================================================
0xFFFF and 0x0000 Reserved
0x8000-0xFFFE Expert Review
0x0001-0x7F00 First Come, First Served
0x7F01-0x7FE0 Experimental
0x7FE1-0x7FFF Private Use
Table 1: Registration procedures for the PDU Identifier registry
Initially, IANA will assign the "PDU Identifier" registry with the
values in Table 2:
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Value Description Reference
===================================================
0xACE1 Test Setup PDU <this RFC>
0xACE2 Test Activation PDU <this RFC>
0xDEAD Null PDU <this RFC>
0xBEEF Load PDU <this RFC>
0xFEED Status Feedback PDU <this RFC>
Table 2: Initial PDU Identifier Values
11.2.2. Protocol Version Registry
IANA will create the "Protocol Version" registry under the "UDP Speed
Test Protocol (UDPSTP)" registry group. UDPST Protocol Test Setup
Request, Test Setup Response and Test Activation Request PDUs contain
a two octet protocolVer field, identifying the version of the
protocol in use. The code points in this registry are allocated
according to the registration procedures [RFC8126] described in
Table 3.
Range(Decimal) Registration Procedures
===============================================================
0-19 Reserved
20-40960 IETF Review
40961-53248 First Come, First Served
53249-65534 Experimental
65535 Reserved
Table 3: Registration procedures for the Protocol Version registry
Initially, IANA will assign the decimal value 20 listed in Table 4 in
the "Protocol Version" registry:
Value Description Reference
================================================
20 Protocol version 20 <this RFC>
Table 4: Initial Protocol Version value
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11.2.3. Test Setup PDU Modifier Bitmap Registry
IANA will create the "Test Setup PDU Modifier Bitmap" registry under
the "UDP Speed Test Protocol (UDPSTP)" registry group. The Test
Setup PDU layout contains a modifierBitmap field. The bitmaps in
this registry are allocated according to the registration procedures
[RFC8126] described in Table 5.
Range(Bitmap) Registration Procedures
===============================================================
00000000-01111111 IETF Review
10000000 Reserved
Table 5: Registration procedures for the Test Setup PDU Modifier
Bitmap Registry
Initially, IANA will assign the bitmap values defined by Table 6 in
the "Test Setup PDU Modifier Bitmap" registry.
Value Description Reference
===============================================================
0x00 No modifications <this RFC>
0x01 Allow Jumbo datagram <this RFC>
sizes above sending
rates of 1Gbps
0x02 Use Traditional MTU <this RFC>
(1500 bytes with
IP-header)
Table 6: Initial Test Setup PDU Modifier Bitmap values
11.2.4. Test Setup PDU Authentication Mode Registry
IANA will create the "Test Setup PDU Authentication Mode" registry
under the "UDP Speed Test Protocol (UDPSTP)" registry group. The
Test Setup PDU layout contains an authMode field. The code points in
this registry are allocated according to the registration procedures
[RFC8126] described in Table 7.
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Range(Decimal) Registration Procedures
===============================================================
0-59 IETF Review
60-63 Experimental
64-255 Reserved
Table 7: Registration procedures for the Test Setup PDU
Authentication Mode registry
Initially, IANA will assign the decimal values defined by Table 8 in
the "Test Setup PDU Authentication Mode" registry.
Value Description Reference
===============================================================
0 Optional Unauthenticated mode <this RFC>
1 Required authentication <this RFC>
for the Control phase
2 Optional authentication for <this RFC>
the Data phase, in addition
to the Control phase
3 Optional encrypted mode <this RFC>
Table 8: Initial Test Setup PDU Authentication Mode values
11.2.5. Test Setup PDU Command Response Field Registry
IANA will create the "Test Setup PDU Command Response Field"
registry" under the "UDP Speed Test Protocol (UDPSTP)" registry
group. The Test Setup PDU layout contains a cmdResponse field. The
code points in this registry are allocated according to the
registration procedures [RFC8126] described in Table 9.
Range(Decimal) Registration Procedures
===============================================================
0-127 IETF Review
128-239 First Come, First Served
240-249 Experimental
250-254 Private Use
255 Reserved
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Table 9: Registration procedures for the Test Setup PDU Command
Response Field Registry
Initially, IANA will assign the decimal values defined by Table 10 in
the "Test Setup PDU Command Response Field" registry.
Value Description Reference
===============================================================
0 None (used by <this RFC>
client in Request)
1 Acknowledgment <this RFC>
2 Bad Protocol Version <this RFC>
3 Invalid Jumbo datagram <this RFC>
option
4 Unexpected Authentication <this RFC>
in Setup Request
5 Authentication missing <this RFC>
in Setup Request
6 Invalid authentication <this RFC>
method
7 Authentication failure <this RFC>
8 Authentication time is <this RFC>
invalid in Setup Request
9 No Maximum test Bit rate <this RFC>
specified
10 Server Maximum Bit rate <this RFC>
exceeded
11 MTU option does not match <this RFC>
server
12 Multi-connection parameters <this RFC>
rejected by server
13 Connection allocation <this RFC>
failure on server
Table 10: Initial Test Setup PDU Command Response Field values
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11.2.6. Test Activation PDU Command Request Registry
IANA will create the "Test Activation PDU Command Request" registry
under the "UDP Speed Test Protocol (UDPSTP)" registry group. The
Test Setup PDU layout contains a cmdRequest field. The code points
in this registry are allocated according to the registration
procedures [RFC8126] described in Table 11.
Range(Decimal) Registration Procedures
===============================================================
0-127 IETF Review
128-239 First Come, First Served
240-249 Experimental
250-254 Private Use
255 Reserved
Table 11: Registration procedures for the Test Activation PDU Command
Request registry
Initially, IANA will assign the decimal values defined by Table 12 in
the "Test Activation PDU Command Request" registry.
Value Description Reference
===============================================================
0 No Request <this RFC>
1 Request test in Upstream <this RFC>
direction (client to server)
2 Request test in Downstream <this RFC>
direction (server to client)
Table 12: Initial Test Activation PDU Command Request values
11.2.7. Test Activation PDU Modifier Bitmap Registry
IANA will create the "Test Activation PDU Modifier Bitmap" registry
under the "UDP Speed Test Protocol (UDPSTP)" registry group. The
Test Activation PDU layout (also) contains a modifierBitmap field.
The bitmaps in this registry are allocated according to the
registration procedures [RFC8126] described in Table 13.
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Range(Bitmap) Registration Procedures
===============================================================
00000000-01111111 IETF Review
10000000 Reserved
Table 13: Registration procedures for the Test Activation PDU
Modifier Bitmap registry
Initially, IANA will assign the bitmap values defined by Table 14 in
the "Test Activation PDU Modifier Bitmap" registry.
Value Description Reference
===============================================================
0x00 No modifications <this RFC>
0x01 Set when srIndexConf is <this RFC>
start rate for search
0x02 Set for randomized <this RFC>
UDP payload
Table 14: Initial Test Activation PDU Modifier Bitmap values
11.2.8. Test Activation PDU Rate Adjustment Algo. Registry
The Test Activation PDU layout contains a rateAdjAlgo field. The
table below defines the assigned Capitalized alphabetic UTF-8 values
in the registry.
IANA will create the "Test Activation PDU Rate Adjustment Algo."
registry under the "UDP Speed Test Protocol (UDPSTP)" registry group.
The Test Activation PDU layout contains a rateAdjAlgo field. The
code points in this registry are allocated according to the
registration procedures [RFC8126] described in Table 15.
Range(Capital alphabet. UTF-8) Registration
Procedures
===============================================================
A-Q IETF Review
R-V Experimental
W-Y Private Use
Z Reserved
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Table 15: Registration procedures for the Test Activation PDU Rate
Adjustment Algo. registry
Initially, IANA will assign the Capitalized alphabetic UTF-8 values,
as well as the corresponding incremental numeric, defined by Table 16
in the "Test Activation PDU Rate Adjustment Algo." registry.
Value Description Reference
(Numeric)
===================================================
A(n/a) Not used <this RFC>
B(0) Rate algorithm Type B <this RFC>
C(1) Rate algorithm Type C <this RFC>
Table 16: Initial Test Activation PDU Rate Adjustment Algo. values
11.2.9. Test Activation PDU Command Response Field Registry
IANA will create the "Test Activation PDU Command Response Field"
registry under the "UDP Speed Test Protocol (UDPSTP)" registry group.
The Test Activation PDU layout (also) contains a cmdResponse field.
The code points in this registry are allocated according to the
registration procedures [RFC8126] described in Table 17.
Range(Decimal) Registration Procedures
===============================================================
0-127 IETF Review
128-239 First Come, First Served
240-249 Experimental
250-254 Private Use
255 Reserved
Table 17: Registration procedures for the Test Activation PDU Command
Response Field registry
Initially, IANA will assign the decimal values defined by Table 18 in
the "Test Activation PDU Command Response Field" registry.
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Value Description Reference
===============================================================
0 None (used by <this RFC>
client in Request)
1 Server Acknowledgment <this RFC>
2 Server indicates an error <this RFC>
Table 18: Initial Test Activation PDU Command Response Field values
11.3. Guidelines for the Designated Experts
It is suggested that multiple designated experts be appointed for
registry change requests.
Criteria that should be applied by the designated experts include
determining whether the proposed registration duplicates existing
entries and whether the registration description is clear and fits
the purpose of this registry.
Registration requests are evaluated within a two-week review period
on the advice of one or more designated experts. Within the review
period, the designated experts will either approve or deny the
registration request, communicating this decision to IANA. Denials
should include an explanation and, if applicable, suggestions as to
how to make the request successful.
12. Acknowledgments
This document was edited by Al Morton, who passed away before being
able to finalize this work. Ruediger Geib only joined later to help
finalizing this draft.
Thanks to Lincoln Lavoie, Can Desem, Greg Mirsky, Bjoern Ivar Teigen,
Ken Kerpez and Chen Li for reviewing this draft and providing helpful
suggestions and areas for further development. Mohamed Boucadair's
AD review improved comprehensability of the document. David Dong and
Amanda Baber provided early reviews of the IANA Considerations
section.
Brian Weis provided an early SEC-DIR review; version 02 captures
clarifications and version 03-09 took up on the protocol changes
which Brian suggested. Tommy Pauly sheperded this document.
13. References
13.1. Normative References
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[FIPS-197] National Institute of Standards and Technology, NIST.,
"Federal Information Processing Standards Publication 197
(FIPS-197), ADVANCED ENCRYPTION STANDARD (AES)", 26
November 2001, <https://nvlpubs.nist.gov/nistpubs/fips/
nist.fips.197.pdf>.
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/info/rfc768>.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
<https://www.rfc-editor.org/info/rfc4086>.
[RFC5044] Culley, P., Elzur, U., Recio, R., Bailey, S., and J.
Carrier, "Marker PDU Aligned Framing for TCP
Specification", RFC 5044, DOI 10.17487/RFC5044, October
2007, <https://www.rfc-editor.org/info/rfc5044>.
[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011,
<https://www.rfc-editor.org/info/rfc6234>.
[RFC7210] Housley, R., Polk, T., Hartman, S., and D. Zhang,
"Database of Long-Lived Symmetric Cryptographic Keys",
RFC 7210, DOI 10.17487/RFC7210, April 2014,
<https://www.rfc-editor.org/info/rfc7210>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
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[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8899] Fairhurst, G., Jones, T., Tüxen, M., Rüngeler, I., and T.
Völker, "Packetization Layer Path MTU Discovery for
Datagram Transports", RFC 8899, DOI 10.17487/RFC8899,
September 2020, <https://www.rfc-editor.org/info/rfc8899>.
[RFC9097] Morton, A., Geib, R., and L. Ciavattone, "Metrics and
Methods for One-Way IP Capacity", RFC 9097,
DOI 10.17487/RFC9097, November 2021,
<https://www.rfc-editor.org/info/rfc9097>.
13.2. Informative References
[CBC] Dworkin, M., "NIST Special Publication 800-38A:
Recommendation for Block Cipher Modes of Operation:
Methods and Techniques, U.S. National Institute of
Standards and Technology", December 2001,
<https://csrc.nist.gov/pubs/sp/800/38/a/final>.
[RFC3148] Mathis, M. and M. Allman, "A Framework for Defining
Empirical Bulk Transfer Capacity Metrics", RFC 3148,
DOI 10.17487/RFC3148, July 2001,
<https://www.rfc-editor.org/info/rfc3148>.
[RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
Zekauskas, "A One-way Active Measurement Protocol
(OWAMP)", RFC 4656, DOI 10.17487/RFC4656, September 2006,
<https://www.rfc-editor.org/info/rfc4656>.
[RFC5136] Chimento, P. and J. Ishac, "Defining Network Capacity",
RFC 5136, DOI 10.17487/RFC5136, February 2008,
<https://www.rfc-editor.org/info/rfc5136>.
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
RFC 5357, DOI 10.17487/RFC5357, October 2008,
<https://www.rfc-editor.org/info/rfc5357>.
[RFC7497] Morton, A., "Rate Measurement Test Protocol Problem
Statement and Requirements", RFC 7497,
DOI 10.17487/RFC7497, April 2015,
<https://www.rfc-editor.org/info/rfc7497>.
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[RFC7594] Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
Aitken, P., and A. Akhter, "A Framework for Large-Scale
Measurement of Broadband Performance (LMAP)", RFC 7594,
DOI 10.17487/RFC7594, September 2015,
<https://www.rfc-editor.org/info/rfc7594>.
[RFC8337] Mathis, M. and A. Morton, "Model-Based Metrics for Bulk
Transport Capacity", RFC 8337, DOI 10.17487/RFC8337, March
2018, <https://www.rfc-editor.org/info/rfc8337>.
[RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple
Two-Way Active Measurement Protocol", RFC 8762,
DOI 10.17487/RFC8762, March 2020,
<https://www.rfc-editor.org/info/rfc8762>.
[RFC8799] Carpenter, B. and B. Liu, "Limited Domains and Internet
Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
<https://www.rfc-editor.org/info/rfc8799>.
[RFC9145] Boucadair, M., Reddy.K, T., and D. Wing, "Integrity
Protection for the Network Service Header (NSH) and
Encryption of Sensitive Context Headers", RFC 9145,
DOI 10.17487/RFC9145, December 2021,
<https://www.rfc-editor.org/info/rfc9145>.
[TR-471] Morton, A,, Editor., "Broadband Forum TR-471: IP Layer
Capacity Metrics and Measurement, Issue 4", September
2024, <https://www.broadband-forum.org/technical/download/
TR-471.pdf>.
[Y.1540] ITU-T, "Internet protocol data communication service - IP
packet transfer and availability performance parameters",
ITU-T Recommendation Y.1540, December 2019,
<https://www.itu.int/rec/T-REC-Y.1540-201912-I/en>.
Authors' Addresses
Len Ciavattone
AT&T Labs
Middletown, NJ
United States of America
Email: lenciavattone@gmail.com
Ciavattone & Geib Expires 8 November 2025 [Page 58]
Internet-Draft Test Protocol: IP Capacity Measurement May 2025
Ruediger Geib
Deutsche Telekom
Deutsche Telekom Allee 9
64295 Darmstadt
Germany
Phone: +49 6151 5812747
Email: Ruediger.Geib@telekom.de
Ciavattone & Geib Expires 8 November 2025 [Page 59]