Internet DRAFT - draft-ietf-ippm-capacity-protocol
draft-ietf-ippm-capacity-protocol
Network Working Group L. Ciavattone
Internet-Draft AT&T Labs
Intended status: Standards Track R. Geib
Expires: 24 August 2024 Deutsche Telekom
21 February 2024
Test Protocol for One-way IP Capacity Measurement
draft-ietf-ippm-capacity-protocol-07
Abstract
This memo addresses the problem of protocol support for measuring
Network Capacity metrics in RFC 9097, where the method deploys a
feedback channel from the receiver to control the sender's
transmission rate in near-real-time. This memo defines a simple
protocol to perform the RFC 9097 (and other) 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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 24 August 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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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provided without warranty as described in the Revised BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Scope, Goals, and Applicability . . . . . . . . . . . . . . . 4
3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5
4. Parameters and Security-related Operations . . . . . . . . . 7
4.1. Parameters and Definitions . . . . . . . . . . . . . . . 7
4.2. Security Mode Operations . . . . . . . . . . . . . . . . 7
4.2.1. Mode 0: OPTIONAL Unauthenticated mode . . . . . . . . 7
4.2.2. Mode 1: REQUIRED authentication mode . . . . . . . . 8
4.2.3. Mode 2: OPTIONAL authentication for Data phase . . . 8
4.2.4. Mode 3: OPTIONAL Partial Encryption - Control and
Status Feedback . . . . . . . . . . . . . . . . . . . 9
4.2.5. OPTIONAL Fully Encrypted mode - For Information
Only . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3. Key Management . . . . . . . . . . . . . . . . . . . . . 12
4.4. Firewall Configuration . . . . . . . . . . . . . . . . . 13
5. Test Setup Request and Response . . . . . . . . . . . . . . . 13
5.1. Client Generates Test Setup Request . . . . . . . . . . . 13
5.1.1. Authenticated Modes . . . . . . . . . . . . . . . . . 17
5.1.2. Unauthenticated Mode . . . . . . . . . . . . . . . . 17
5.1.3. Partial Encrypted Mode . . . . . . . . . . . . . . . 17
5.2. Server Processes Test Setup Request and Generates
Response . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2.1. Test Setup Request Processing - Rejection . . . . . . 17
5.2.2. Test Setup Request Processing - Acceptance . . . . . 19
5.3. Setup Response Processing at the Client . . . . . . . . . 22
6. Test Activation Request and Response . . . . . . . . . . . . 23
6.1. Client Generates Test Activation Request . . . . . . . . 23
6.2. Server Processes Test Activation Request and Generates
Response . . . . . . . . . . . . . . . . . . . . . . . . 27
6.2.1. Server Rejects or Modifies Request . . . . . . . . . 27
6.2.2. Server Accepts Request and Generates Response . . . . 28
6.3. Client Processes Test Activation Response . . . . . . . . 30
7. Test Stream Transmission and Measurement Feedback Messages . 31
7.1. Test Packet PDU and Roles . . . . . . . . . . . . . . . . 31
7.2. Status PDU . . . . . . . . . . . . . . . . . . . . . . . 35
7.2.1. Authenticated Modes . . . . . . . . . . . . . . . . . 42
7.2.2. Unauthenticated Mode . . . . . . . . . . . . . . . . 42
7.2.3. Partial Encrypted Mode . . . . . . . . . . . . . . . 42
8. Stopping the Test . . . . . . . . . . . . . . . . . . . . . . 42
9. Method of Measurement . . . . . . . . . . . . . . . . . . . . 43
9.1. Notes on Interface Measurements . . . . . . . . . . . . . 43
10. Security Considerations . . . . . . . . . . . . . . . . . . . 44
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 45
11.1. New System Port Assignment . . . . . . . . . . . . . . . 45
11.2. New UDPST Registry Group . . . . . . . . . . . . . . . . 46
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11.2.1. PDU Identifier Registry . . . . . . . . . . . . . . 46
11.2.2. Protocol Number Registry . . . . . . . . . . . . . . 46
11.2.3. Test Setup PDU Modifier Bitmap Registry . . . . . . 47
11.2.4. Test Setup PDU Authentication Mode Registry . . . . 47
11.2.5. Test Setup PDU Command Response Field Registry . . . 48
11.2.6. Test Activation PDU Modifier Bitmap Registry . . . . 50
11.2.7. Test Activation PDU Command Request Registry . . . . 50
11.2.8. Test Activation PDU Rate Adjustment Algo.
Registry . . . . . . . . . . . . . . . . . . . . . . 50
11.2.9. Test Activation PDU Command Response Field
Registry . . . . . . . . . . . . . . . . . . . . . . 51
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 51
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 52
13.1. Normative References . . . . . . . . . . . . . . . . . . 52
13.2. Informative References . . . . . . . . . . . . . . . . . 53
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 56
1. Introduction
The IETF's efforts to define Network and Bulk Transport Capacity have
been chartered and finally progressed after over twenty years.
In that time, the performance community has seen development of
Informative definitions in [RFC3148] for Framework for Bulk Transport
Capacity (BTC), RFC 5136 for Network Capacity and Maximum IP-layer
Capacity, and the Experimental metric definitions and methods in
[RFC8337], Model-Based Metrics for BTC.
This memo looks at the problem of measuring Network Capacity metrics
defined in [RFC9097] where the method deploys a feedback channel from
the receiver to control the sender's transmission rate in near-real-
time.
Although there are several test protocols already available for
support and management of active measurements, this protocol is a
major departure from their operation:
1. UDP transport, not TCP, is used for Control phase messages (e.g.,
Test Setup, Test Activation) and Data phase messages (e.g., Load,
Status Feedback).
2. TWAMP [RFC5357] and STAMP [RFC8762] use the philosophy that one
host is a Session-Reflector, sending test packets every time they
receive a test packet. This protocol supports a one-way test
with periodic Status Feedback messages returned to the sender.
These messages are also a basis for on-path round-trip delay
measurements, which are a key input to the load rate adjustment
algorithm.
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3. OWAMP [RFC4656] supports one-way testing with results Fetch at
the end of the test session. This protocol supports a one-way
test and requires periodic Status Feedback messages returned to
the sender to support the load rate adjustment algorithm.
4. The security features of OWAMP [RFC4656] and TWAMP [RFC5357] have
been described as "unusual", to the point that IESG approved
their use while also asking that these methods not be used again.
Further, the common OWAMP [RFC4656] and TWAMP [RFC5357] approach
to security is over 15 years old at this time.
Note: the -00 update of this draft will be the last that describes
version 8 of the protocol in the running code. Updates -01 and -02
of the draft correspond to version 9 of the protocol, which strives
to allow interoperability with version 8. The -03, -04, and -05
updates of the draft incorporate new security modes of operation, and
correspond to version 10 of the protocol. After additional
refinements, versions -06 and beyond will utilize a protocol version
of 20.
Ruediger Geib joined the team of authors to help completing this
draft. He's not replacing Al Morton, as Al can't be replaced.
1.1. 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 memo is to define a protocol to measure the Maximum
IP-Layer Capacity metric and according to the standardized method.
We note that 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 continued 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.
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All active testing protocols currently defined by the IPPM WG are
UDP-based, but this protocol specifies both control and test
protocols using UDP transport. Also, a feedback message stream
continues operating during testing to convey results and dynamic
configurations.
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.
3. Protocol Overview
This section gives an informative overview of the communication
protocol between two test end-points (without expressing requirements
or describing the authentication and encryption aspects; later
sections provide these details and requirements).
One end-point takes the role of server, listening for connection
requests on a well-known destination port from the other end-point,
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 of the server in order to begin the setup and configuration
exchanges with the server.
Additionally, multi-connection (multi-flow) testing is inherently
supported by the protocol. Each connection is essentially
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 logistically as well
as aggregate the individual test results into an overall set of
performance statistics. Fields in the control messages (mcIndex,
mcCount, and mcIdent) exist to both differentiate and associate the
multiple connections that comprise a single test.
The protocol uses UDP transport and has four types of exchanges in
two phases. Exchanges 1 and 2 constitute the Control phase, while
exchanges 3 and 4 constitute the Data phase.
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1. Setup Request and Response Exchange: The client 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. The server
also communicates the ephemeral port for further communication
when accepting the client's request.
2. Test Activation Request and Response: 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. 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) and the traffic that follows. If the Test
Activation Request is rejected or fails, the client assumes that
the firewall will close the address/port combination after the
firewall's configured idle traffic timeout.
3. Test Stream Transmission and Measurement Feedback Messages:
Testing proceeds with one end-point sending Load PDUs and the
other end-point 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.
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
combination after the firewall's configured idle traffic timeout.
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5. Both the client and server react to unexpected interruptions in
the Control and Data phase. Watchdog timers limit the time a
server or client will wait before stopping all traffic and
terminating a test.
4. Parameters and Security-related Operations
4.1. Parameters and Definitions
For Parameters related to the Maximum IP-Layer Capacity Metric and
Method, please see Section 4 of [RFC9097].
4.2. Security Mode Operations
There are four security modes of operation:
1. A REQUIRED mode with authentication during the Control phase:
Test Setup and Test Activation exchanges.
2. An OPTIONAL mode with the additional authentication of the Status
Feedback messages (not the Load PDUs) during the Data phase.
3. An OPTIONAL Unauthenticated mode for all messages. This mode
SHALL only be permitted when all other modes requiring
authentication (or Partial Encryption) are not permitted.
4. An OPTIONAL mode with encryption of the Control phase exchanges
and the Status Feedback messages.
5. For full encryption, OPTIONAL operation of both Control and Data
phase exchanges inside an encrypted tunnel chosen and
instantiated via a bilateral agreement between the users. This
is not an explicit mode of the protocol itself.
The requirements below refer to the PDUs in the sections that follow,
primarily the authUnixTime field, the authDigest field, and the keyId
field. In an attempt to be more efficient, although somewhat
unconventional, the second half of the 256-bit HMAC-SHA256 hash
within the authDigest is reused as the Initialization Vector (IV).
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 elsewhere.
4.2.1. Mode 0: OPTIONAL Unauthenticated mode
In the OPTIONAL Unauthenticated mode, all PDU senders SHALL set the
authUnixTime field, the authDigest field, and the keyId field of all
packets to all zeroes.
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When the OPTIONAL Unauthenticated mode of operation is allowed, all
other modes requiring authentication (or Partial Encryption) SHALL be
blocked or not supported. Unauthenticated and authenticated modes
SHALL be considered mutually exclusive.
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 authentication mode
In the REQUIRED authentication mode, the client and the server SHALL
be configured to use one of a number of shared secret keys.
During the Control phase, the sender SHALL read the current time and
populate the authUnixTime field, then calculate the authDigest field
of the entire PDU (with the authDigest field set to all zeroes)
according to [RFC6234] and send the packet to the receiver.
Upon reception, the receiver SHALL validate the message PDU for
validity of the authDigest, the authUnixTime field for acceptable
immediacy, correct length, and formatting (PDU-specific fields are
also checked, such as protocol version).
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.
This process SHALL be executed for each 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 authentication for Data phase
When using the OPTIONAL authentication during the Data Phase, the
process SHALL also be applied to the Status PDU. The client sends
the Status PDU in a downstream test, and the server sends it in an
upstream test.
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The Status PDU sender SHALL read the current time and populate the
authUnixTime field, then calculate the authDigest field of the entire
Status PDU (with the authDigest field set to all zeroes) and send the
packet to the receiver.
Upon reception, the receiver SHALL validate the message PDU for
validity of the authDigest, the authUnixTime field for acceptable
immediacy, correct length, and formatting (PDU-specific fields are
also checked, such as protocol version).
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).
If this optional mode has not been selected, then the authUnixTime
field, the authDigest field, and the keyId field of the Status PDU
(see Section 7.2) SHALL be populated with all zeroes.
4.2.4. Mode 3: OPTIONAL Partial Encryption - Control and Status
Feedback
This mode incorporates Authenticated mode 2, which includes all
control and Status Feedback messages. The encryption algorithm only
provides encryption and relies on the existing authentication
mechanism to provide integrity protection. This mode re-uses several
protocol fields, which is reasonable since both authentication and
encryption are provided (the field format is presented in later
sections).
When using the OPTIONAL Partial 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 Partial 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:
1. Advanced Encryption Standard, AES, according to Federal
Information Processing Standards Publication 197 [FIPS-197]
2. Cipher Block Chaining (CBC) [CBC]
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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 (intending to use encryption) SHALL read the current time
and populate the authUnixTime field of the request packet, setting
any padding or reserved fields to zero, and then calculate (and
populate) the authDigest, for the entire PDU, in the same manner as
specified with Authentication mode 1 and 2. The sender SHALL then
encrypt the header up to and including the first half (128 bits) of
the 256-bit HMAC-SHA256 hash within the authDigest field. The second
half of the HMAC-SHA256 hash within the authDigest field (128 bits)
will be used as the Initialization Vector (IV). The IV and any
subsequent fields SHALL be communicated in the clear. Finally, the
sender SHALL send the packet with partially encrypted PDU to the
receiver.
Upon reception, the receiver SHALL decrypt the PDU using the included
IV and shared key. Then, check the message PDU for validity via the
authDigest, the authUnixTime field for acceptable immediacy, and
general formatting such as protocol version. Finally, the PDU-
specific fields that control the test are 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 as described above, and the packet
with encrypted PDU SHALL be sent back to the originator.
This process SHALL be executed for each request and response in the
Test Setup exchange, including the Null Request, (Section 5), the
Test Activation exchange (Section 6), and the Status Feedback PDUs.
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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).
4.2.5. OPTIONAL Fully Encrypted mode - For Information Only
Two users may wish to make private measurements as part of a
bilateral agreement, and they might achieve this goal by encrypting
the traffic of this protocol. However, there is no advantage in a
native-protocol mode to encrypt all traffic when industry solutions
for encrypted tunnels are widespread and users can deploy the tunnel
technology of their choice ([RFC6071] for IPsec and [RFC8446] for
TLS).
Although it was suggested, DTLS [RFC9147] could not be the basis for
a mode with encryption of all the PDUs. The replay protection would
remove duplicated packets and prevent transparent measurement of this
impairment.
The protocol's operation is mostly independent from the tunnel
operation, but reject messages during the Control phase MAY be sent,
the same as when configuring the server for troubleshooting. Also,
the additional encapsulation header size will likely limit the
maximum UDP payload possible in the Full Encryption mode, and users
may need to account for the smaller limit.
Operation of both Control and Data phases inside an encrypted tunnel
would provide a measure of privacy for all protocol operations, but
the cost could be inaccurate measurements (from the additional
processing overhead on Load PDUs at Gigabit rates) and reduced scale
(when considering a server's capacity to host test sessions).
The primary scope of this protocol is Internet access measurement.
This scope greatly limits the geography of the eavesdropping attack
surface, and encourages user-selected encryption solutions when
needed (although this need may be more likely when the protocol is
used beyond its intended scope). IPPM protocols that have been
deployed in this scope have not used the encryption option, and at
least one of these protocols [TWAMP] has been deployed at great scale
without using the encrypted mode.
The key pieces of information exposed by the protocol are found in
the Status Feedback messages which are transferred every 50ms with
default timing. The Status Feedback messages contain either detailed
measurements of the previous time interval in a downstream test, or
additionally the next sending rate for the sender in an upstream
test. If the Status Feedback messages are encrypted and decrypted,
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then the processing time may affect the RTT (Round-Trip Time)
measurements and affect the protocol operation, especially the load
rate adjustment algorithm. Thus, the processing time is a key
concern for low cost CPE (e.g., residential gateways hosting the
client function). The test configuration information exchanged
elsewhere is considered mundane.
The tunnel approach has some advantages. Some users may want to
characterize the encrypted tunnel in comparison to transport in the
clear. It is RECOMMENDED to use the Unauthenticated mode to maximize
server and client performance for the clear transport case, but some
may wish to use an Authenticated mode. Users can also leave the
encrypted tunnel up when conducting repeating tests, and reduce test
setup time to the minimum.
4.3. Key Management
Section 2 of [RFC7210] specifies a conceptual database for long-lived
cryptographic keys. The database is implemented as a plaintext
table, to allow text editor maintenance of the key table. 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 Partial Encryption
mode, when used.
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 protocol
field in the PDUs that follow, keyId.
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4.4. Firewall Configuration
Normal firewall configuration allows a host to open a bidirectional
connection using unique source and destination addresses and port
numbers by sending a packet using that set of 4-tuple values. 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 well-known UDP port of the server.
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.
5. Test Setup Request and Response
All messages defined in this section SHALL use UDP transport. The
hosts SHALL calculate and include the UDP checksum, or check the UDP
checksum as necessary.
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 (well-known) control port.
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
(close the UDP socket and indicate an error message to the user).
Lost messages SHALL NOT be retransmitted. The test initiation timer
MAY reuse the test termination timeout value.
As of version 9, 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 Setup Request/Response message PDU SHALL be organized as follows:
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//
// Control header for UDP payload of Setup Request/Response PDUs
//
struct controlHdrSR {
#define CHSR_ID 0xACE1
uint16_t controlId; // Control ID
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
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 octet
uint8_t padding[12]; // Padding for encryption
//
uint32_t authUnixTime; // Authentication time stamp
#define AUTH_DIGEST_LENGTH 32 // SHA-256 digest length
uint8_t authDigest[AUTH_DIGEST_LENGTH] // HMAC
#define AUTH_IV_LENGTH 16 // Initialization Vector (IV)
#define AUTH_DIGEST_IV (AUTH_DIGEST_LENGTH - AUTH_IV_LENGTH)
// IV = &authDigest[AUTH_DIGEST_IV] (not encrypted)
#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 Control+Status
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uint8_t authMode; // Authentication mode (not encrypted)
uint8_t keyId; // Key ID in shared table (not encrypted)
uint16_t reserved; // reserved octets (not encrypted)
};
Figure 1: Test Setup PDU
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| controlId | protocolVer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mcIndex | mcCount | mcIdent |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| cmdRequest | cmdResponse | maxBandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| testPort |modifierBitmap | reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| padding (96 bits) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authUnixTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| authDigest (256 bits) |
| |
| _ _ _ _ _ _ _ _ _ _ _ |
| |
| Initialization Vector (128 bits) |
| [Reuses second half of HMAC within authDigest] |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authMode | keyId | reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Test Setup PDU Layout
Additional details regarding the Setup Request and Response fields
are as follows:
mcIndex: The index (0,1,2,...) of a connection relative to all
connections that make up a single test. It is used to differentiate
separate connections within a multi-connection test.
mcCount: The total count of attempted connections.
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mcIdent: A pseudorandom non-zero identifier (via RNG, source port
number,...) that is common to all connections of a single test. It
is used to associate separate connections within a multi-connection
test.
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. The server compares this value to its currently
available configured limit for test admission control. This field
MAY optionally be used for rate-limiting the maximum rate the server
should attempt. The CHSR_USDIR_BIT bit is set to 0 by default to
indicate "downstream" and has to be set to 1 to indicate "upstream".
testPort: The UDP ephemeral port number on the server that the client
SHALL use for the Test Activation Request and subsequent Load or
Status PDUs.
modifierBitmap: There are two bits currently assigned in this bitmap:
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).
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 currently undefined. A new registry will be
needed for modifierBitmap assignments; see the IANA Considerations
section.
authDigest (and Initialization Vector, IV) field: This field contains
the 256-bit HMAC-SHA256 hash. In Partial Encrypted mode, the second
half of the hash within this field (128 bits) is reused as the
Initialization Vector (IV).
authMode: The authMode field currently has four values assigned:
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)
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AUTHMODE_3: OPTIONAL partial encrypted mode
plus, a range of values for experimentation: 60 through 63. A new
registry will be needed for mode values; see the IANA Considerations
section.
keyId: This is a localKeyName, the numeric key identifier for a key
in the shared key table.
5.1.1. Authenticated Modes
When operating in either of the Authenticated modes (authMode 1 and
authMode 2), the client SHALL follow the requirements of
Section 4.2.2 (and 4.2.3 if applicable), and SHALL generate the
authDigest field. The HMAC-SHA256 calculation SHALL cover all fields
in the header. The current Unix time SHALL be read and inserted
immediately prior to the calculation (as immediately as possible).
Computation of the authDigest HMAC-SHA256 hash is specified in
[RFC6234].
5.1.2. Unauthenticated Mode
When operating in Unauthenticated mode, the requirements of
Section 4.2.1 SHALL be followed.
5.1.3. Partial Encrypted Mode
When operating in the Partial Encryption mode, the client SHALL
follow the requirements of Section 4.2.4 and SHALL encrypt the PDU up
to, but not including, the Initialization Vector (IV) or beyond.
5.2. Server Processes Test Setup Request and Generates Response
This section describes the processes at the server to evaluate the
Test Setup Request and determine the next steps.
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
interrogate the authMode field
* if operating in the Partial Encryption mode, use the available
keyId and IV to decrypt the Setup Request message up to the IV
using the method prescribed in Section 4.2.4
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* 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 then proceed to evaluate the other fields in the protocol header,
such as the protocol version, the Control 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). The value in the authUnixTime field is
a 32-bit time stamp and a 5 minute tolerance window (+/- 2.5 minutes)
SHALL be used (if in one of the Authenticated modes) to distinguish a
subsequent replay of a Test Setup PDU.
The authUnixTime field is expected to be zeroed in Unauthenticated
mode.
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.
The server SHALL follow the requirements of Section 4.2.2 and
insert an updated authUnixTime and authDigest in the response.
* 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.
* 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:
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1. the Setup Request PDU size is not correct,
2. the Control ID is invalid, 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 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 an error code (starting at
CHSR_CRSP_BADVER), 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 authUnixTime field is updated to the current time and the
authDigest is recalculated, if doing authentication.
* The PDU is encrypted, up to the IV, if doing encryption.
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 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.
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:
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* 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 authUnixTime field is updated to the current time and the
authDigest is recalculated, if doing authentication.
* The PDU is encrypted, up to the IV, if doing encryption.
Finally, the new UDP connection associated with the new socket and
port number is opened, 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
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 Null Request message PDU SHALL be organized as follows:
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//
// Control header for UDP payload of Null Request PDU
//
struct controlHdrNR {
#define CHNR_ID 0xDEAD
uint16_t controlId; // Control ID
uint16_t protocolVer; // Protocol version
uint8_t mcIndex; // Multi-connection index
uint8_t mcCount; // Multi-connection count
uint16_t mcIdent; // Multi-connection identifier
#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 reserved1; // reserved octets
//
uint32_t authUnixTime; // Authentication time stamp
uint8_t authDigest[AUTH_DIGEST_LENGTH] // HMAC
// IV = &authDigest[AUTH_DIGEST_IV] (not encrypted)
uint8_t authMode; // Authentication mode (not encrypted)
uint8_t keyId; // Key ID in shared table (not encrypted)
uint16_t reserved; // reserved octets (not encrypted)
};
Figure 3: Null Request PDU
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| controlId | protocolVer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mcIndex | mcCount | mcIdent |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| cmdRequest | cmdResponse | reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authUnixTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| authDigest (256 bits) |
| |
| _ _ _ _ _ _ _ _ _ _ _ |
| |
| Initialization Vector (128 bits) |
| [Reuses second half of HMAC within authDigest] |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authMode | keyId | reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Null Request PDU Layout
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.
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 the Partial Encryption mode, use the available
keyId and IV to decrypt the Setup Response message up to the IV
using the method prescribed in Section 4.2.4
* if operating in one of the Authenticated modes, validate the Setup
Response message by checking the authDigest as prescribed in
Section 4.2.2
and then proceed to evaluate the other fields in the protocol,
beginning with the protocol version, Control ID (to validate the type
of message), and cmdRequest for the role of the message (SHOULD be
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Test Setup Response). The value in the authUnixTime field is a
32-bit timestamp with a 5 minute tolerance window (+/- 2.5 minutes)
and SHALL be used (if in one of the Authenticated modes) to
distinguish a subsequent replay of the message.
The authUnixTime field is expected to be zeroed in Unauthenticated
mode.
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
above, 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.
All messages defined in this section SHALL use UDP transport. The
hosts SHALL calculate and include the UDP checksum, or check the UDP
checksum as necessary.
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 well-known port).
The Test Activation Request/Response message PDU (as well as the
included Sending Rate structure) SHALL be organized as follows:
//
// 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
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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 controlId; // Control ID
uint16_t protocolVer; // Protocol version
uint8_t mcIndex; // Multi-connection index
uint8_t mcCount; // Multi-connection count
uint16_t mcIdent; // Multi-connection identifier
#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 octet
struct sendingRate srStruct; // Sending rate structure
//
uint32_t authUnixTime; // Authentication time stamp
uint8_t authDigest[AUTH_DIGEST_LENGTH] // HMAC
// IV = &authDigest[AUTH_DIGEST_IV] (not encrypted)
uint8_t authMode; // Authentication mode (not encrypted)
uint8_t keyId; // Key ID in shared table (not encrypted)
uint16_t reserved; // reserved octets (not encrypted)
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};
Figure 5: Test Activation PDU
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| txInterval1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| udpPayload1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| burstSize1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| txInterval2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| udpPayload2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| burstSize2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| controlId | protocolVer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mcIndex | mcCount | mcIdent |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| cmdRequest | cmdResponse | lowThresh |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| upperThresh | trialInt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| testIntTime | subIntPeriod | ipTosByte |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| srIndexConf | useOwDelVar |highSpeedDelta |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| slowAdjThresh | seqErrThresh |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ignoreOooDup |modifierBitmap | rateAdjAlgo | reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. srStruct (28 octets) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authUnixTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
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| authDigest (256 bits) |
| |
| _ _ _ _ _ _ _ _ _ _ _ |
| |
| Initialization Vector (128 bits) |
| [Reuses second half of HMAC within authDigest] |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authMode | keyId | reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
The content of many of the unique fields in Figures 5 and 6 are
defined in Section 4 of [RFC9097] and Appendix A of [RFC9097].
Additional details are given below.
srStruct: Sending Rate structure, used by the server in a Test
Activation Response for an upstream test, to communicate the
(initial) Load PDU transmisstion 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.
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.
modifierBitmap: There are two bits currently assigned in this bitmap:
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
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header
Other bit positions are currently undefined. A new registry will be
needed for modifierBitmap assignments; see the IANA Considerations
section.
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.
* Test duration/intervals: trialInt, testIntTime, subIntPeriod
* Packet marking: ipTosByte
Coercion is a step toward 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.
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Note that the server also has the option of completely rejecting the
request and sending back an appropriate Command Response value (only
CHTA_CRSP_BADPARAM currently).
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. The server SHALL follow the requirements of
Section 4.2.2 and insert the authDigest in the response.
* 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 correct,
2. the Control ID is invalid, or
3. a directed attack has been detected,
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
Command Response field to CHTA_CRSP_ACKOK
If the client has requested an upstream test, the server SHALL:
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* 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 a 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. Once the
requirements of the chosen security mode have been met, the Test
Activation Response is ready to be sent to the client:
6.2.2.1. Authenticated Modes
When operating in either of the Authenticated modes the server SHALL
follow the requirements of Section 4.2.2 and SHALL generate the
authDigest field. The HMAC-SHA256 calculation SHALL cover all the
fields in the header. The current Unix time SHALL be read and
inserted immediately prior to the calculation (as immediately as
possible). Computation of the authDigest HMAC-SHA256 hash is
specified in [RFC6234].
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6.2.2.2. Unauthenticated Mode
When operating in Unauthenticated mode, the requirements of
Section 4.2.1 SHALL be followed.
6.2.2.3. Partial Encrypted Mode
When operating in the Partial Encryption mode, the client SHALL
follow the requirements of Section 4.2.4 and SHALL then encrypt the
header up to and including the first half (128 bits) of the
authDigest, after the 256-bit HMAC-SHA256 hash has been inserted.
The second half (128 bits) of the HMAC-SHA256 hash within the
authDigest SHALL then be reused as the Initialization Vector (IV).
The IV and any subsequent fields SHALL be communicated in the clear.
6.3. Client Processes Test Activation Response
When the client receives the Test Activation Response, it SHALL:
* When operating in Partial Encryption mode, decrypt the PDU using
the included IV and shared key. Then, check the message PDU for
validity via the authDigest and the authUnixTime field for
acceptable immediacy, if operating in an Authenticated mode.
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 Command Response 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 Command Response value that
is not equal to one of the codes defined above, 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) 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.
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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.
All messages defined in this section SHALL use UDP transport. The
hosts SHALL calculate and include the UDP checksum, or check the
received UDP checksum before further processing, as necessary.
7.1. Test Packet PDU and Roles
Testing proceeds with one end-point sending Load PDUs, based on
transmission parameters from the Sending Rate Table, and the other
end-point 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 end-point.
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
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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) 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.
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.
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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 Load PDU SHALL be organized as follows (followed by any payload
content):
//
// Load header for UDP payload of Load PDUs
//
struct loadHdr {
#define LOAD_ID 0xBEEF
uint16_t loadId; // Load 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 reserved1; // reserved octets
};
Figure 7: Load PDU
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| loadId | testAction | rxStopped |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lpduSeqNo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| udpPayload | spduSeqErr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduTime_sec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduTime_nsec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lpduTime_sec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lpduTime_nsec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttRespDelay | reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. Payload Content... .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Load PDU Layout
Specific details regarding Load PDU fields are as follows:
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 end-
point 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.
Payload Content: All zeroes, all ones, or a pseudorandom binary
sequence.
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 end-point.
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The Status PDUs are a key part of the server-client control loop. To
protect against bit errors (checksum) or on-path attacks (something
stronger), there is a requirement to calculate and include/check the
UDP checksum. Also, Authenticated mode 2 that covers the Status PDU
and will detect bit errors or attempts to replace values in the
original packets.
The Status Feedback message PDU (as well as the included Sub-Interval
Statistics structure) SHALL be organized as follows:
//
// 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 statusId; // Status 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
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)
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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 rttSample; // Last round-trip time sample (ms)
uint8_t delayMinUpd; // Delay minimum(s) updated (BOOL)
uint8_t reserved1; // reserved octet
uint16_t reserved2; // reserved octets
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
uint8_t padding[12]; // Padding for encryption
//
uint32_t authUnixTime; // Authentication time stamp
uint8_t authDigest[AUTH_DIGEST_LENGTH] // HMAC
// IV = &authDigest[AUTH_DIGEST_IV] (not encrypted)
uint8_t authMode; // Authentication mode (not encrypted)
uint8_t keyId; // Key ID in shared table (not encrypted)
uint16_t reserved; // reserved octets (not encrypted)
};
Figure 9: Status PDU
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 |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| deltaTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrLoss |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrOoo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrDup |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarMin |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarMax |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarSum |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarCnt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttMinimum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttMaximum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| statusId | testAction | rxStopped |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduSeqNo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. srStruct (28 octets) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| subIntSeqNo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. sisSav (56 octets) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrLoss |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrOoo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| seqErrDup |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| clockDeltaMin |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarMin |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarMax |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarSum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayVarCnt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttMinimum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rttSample |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| delayMinUpd | reserved1 | reserved2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| tiDeltaTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| tiRxDatagrams |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| tiRxBytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduTime_sec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spduTime_nsec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| padding (96 bits) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authUnixTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| authDigest (256 bits) |
| |
| _ _ _ _ _ _ _ _ _ _ _ |
| |
| Initialization Vector (128 bits) |
| [Reuses second half of HMAC within authDigest] |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| authMode | keyId | reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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:
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.
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seqErrLoss/seqErrOoo/seqErrDup: Loss, out-of-order, and duplicate
totals. Available for both the sub-interval and trial interval.
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.
rttMinimum/rttMaximum (in sisSav): The minimum and maximum RTT delay
variation (rttSample) 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.
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 end-point clocks are
sufficiently synchronized, this will be the minimum one-way delay in
milliseconds. Otherwise, this value may be negative (but still
completely valid for one-way delay variation measurements).
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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.
rttSample: 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.
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 (and encryption) fields and their operation are as
defined previously in Sections 5 and 6.
When a client or server prepares to send the Status PDU, it SHALL:
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7.2.1. Authenticated Modes
When operating in either of the Authenticated modes, it SHALL follow
the requirements of Section 4.2.2 (and 4.2.3 if applicable), and
SHALL generate the authDigest field. The HMAC-SHA256 calculation
SHALL cover all the fields in the header. The current Unix time
SHALL be read and inserted immediately prior to the calculation (as
immediately as possible). Computation of the authDigest HMAC-SHA256
hash is specified in [RFC6234].
7.2.2. Unauthenticated Mode
When operating in Unauthenticated mode, the requirements of
Section 4.2.1 SHALL be followed.
7.2.3. Partial Encrypted Mode
When operating in the Partial Encryption mode, the client SHALL
follow the requirements of Section 4.2.4 and SHALL then encrypt the
header up to and including the first half (128 bits) of the
authDigest, after the 256-bit HMAC-SHA256 hash has been inserted.
The second half (128 bits) of the HMAC-SHA256 hash within the
authDigest SHALL then be reused as the Initialization Vector (IV).
The IV and any subsequent fields SHALL be communicated in the clear.
8. Stopping the 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).
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
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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 end-point will expire (sometimes at one end-point
first), notifications in logs, STDOUT, and/or formatted output SHALL
be made, and the end-point 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 end-point 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 memo.
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 REQUIRED. To
accommodate different host limitations and testing circumstances,
different modes of operation are recommended, 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.
11. IANA Considerations
This memo requests IANA to assign a "well-known" 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 (UDPST)
protocol.
11.1. New System Port Assignment
Service: udpst-control
Transport Protocol: UDP
Assignee: IESG <iesg@ietf.org>
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.
Port Number: <left blank, as instructed>
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11.2. New UDPST Registry Group
This section describes the design of the UDP Speed Test (UDPST)
registry group.
The new registry group SHALL be named, "UDPST Registry".
The following applies to each registry in the sub-sections below:
Registration Procedure: Specification Required
Reference: <This RFC>
Experts: Performance Metrics Experts
Note: TBD
11.2.1. PDU Identifier Registry
The first two octets of the PDUs used in the UDPST protocol identify
the role and format of PDU that follows.
Identifier Value Reference Change Description
Name Controller
===================================================================
controlId 0xACE1 <this RFC> IETF Test Setup PDU
controlId 0xACE2 <this RFC> IETF Test Activation PDU
controlId 0xDEAD <this RFC> IETF Null PDU
loadId 0xBEEF <this RFC> IETF Load PDU
statusId 0xFEED <this RFC> IETF Status Feedback PDU
Other values are unassigned.
11.2.2. Protocol Number Registry
The second two octets of the PDUs used in the UDPST protocol identify
the version of the protocol in use. The table below defines the
assigned decimal values in the registry.
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Field Value Reference Change Description
Name Controller
===================================================================
protocolVer 0-7 <this RFC> IETF Reserved
protocolVer 8 <this RFC> IETF Protocol version 8
protocolVer 9 <this RFC> IETF Protocol version 9
protocolVer 10 <this RFC> IETF Protocol version 10
protocolVer 20 <this RFC> IETF Protocol version 20
Other values are unassigned, with an upper value of 65535.
11.2.3. Test Setup PDU Modifier Bitmap Registry
The Test Setup PDU layout contains a modifierBitmap field. The table
below defines the initial bit assignments in the registry.
Field Value Reference Change Description
Name Controller
===================================================================
modifierBitmap 0x00 <this RFC> IETF No modifications
modifierBitmap 0x01 <this RFC> IETF Allow Jumbo
datagram sizes above
sending rates of 1Gbps
modifierBitmap 0x02 <this RFC> IETF Use Traditional MTU
(1500 bytes with
IP-header)
modifierBitmap 0x03-0xFF IETF Unassigned
11.2.4. Test Setup PDU Authentication Mode Registry
The Test Setup PDU layout contains an authMode field. The table
below defines the assigned decimal values in the registry, and a
range for experimentation.
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Field Value Reference Change Description
Name Controller
=====================================================================
authMode 0 <this RFC> IETF OPTIONAL Unauthenticated mode
authMode 1 <this RFC> IETF REQUIRED authentication
for the Control phase
authMode 2 <this RFC> IETF OPTIONAL authentication
for the Data phase, in
addition to the Control phase
authMode 3 <this RFC> IETF OPTIONAL partial encrypted
mode
authMode 60-63 <this RFC> IETF Range for experimentation
Other values are unassigned, with the upper boundary of 255.
11.2.5. Test Setup PDU Command Response Field Registry
The Test Setup PDU layout contains an cmdResponse field. The table
below defines the assigned decimal values in the registry.
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Field Value Reference Change Description
Name Controller
===================================================================
cmdResponse 0 <this RFC> IETF None (used by
client in Request)
cmdResponse 1 <this RFC> IETF Acknowledgment
cmdResponse 2 <this RFC> IETF Bad Protocol Version
cmdResponse 3 <this RFC> IETF Invalid Jumbo datagram
option
cmdResponse 4 <this RFC> IETF Unexpected Authentication
in Setup Request
cmdResponse 5 <this RFC> IETF Authentication missing in
Setup Request
cmdResponse 6 <this RFC> IETF Invalid authentication
method
cmdResponse 7 <this RFC> IETF Authentication failure
cmdResponse 8 <this RFC> IETF Authentication time is
invalid in Setup Request
cmdResponse 9 <this RFC> IETF No Maximum test Bit rate
specified
cmdResponse 10 <this RFC> IETF Server Maximum Bit rate
exceeded
cmdResponse 11 <this RFC> IETF MTU option does not match
server
cmdResponse 12 <this RFC> IETF Multi-connection parameters
rejected by server
cmdResponse 13 <this RFC> IETF Connection allocation
failure on server
Other values are unassigned, with the upper boundary of 255.
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11.2.6. Test Activation PDU Modifier Bitmap Registry
The Test Activation PDU layout (also) contains a modifierBitmap
field. The table below defines the initial bit assignments in the
registry.
Field Value Reference Change Description
Name Controller
===================================================================
modifierBitmap 0x00 <this RFC> IETF No modifications
modifierBitmap 0x01 <this RFC> IETF Set when srIndexConf is
start rate for search
modifierBitmap 0x02 <this RFC> IETF Set for randomized
UDP payload
modifierBitmap 0x03-0xFF IETF Unassigned
11.2.7. Test Activation PDU Command Request Registry
The Test Activation PDU layout contains a cmdRequest field. The
table below defines the assigned decimal values in the registry.
Field Value Reference Change Description
Name Controller
===================================================================
cmdRequest 0 <this RFC> IETF No Request
cmdRequest 1 <this RFC> IETF Request test in Upstream
direction (client to server)
cmdRequest 2 <this RFC> IETF Request test in Downstream
direction (server to client)
Other values are unassigned, with the upper boundary of 255.
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.
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Field Value Reference Change Description
Name Controller
===================================================================
rateAdjAlgo A <this RFC> IETF Not used
rateAdjAlgo B <this RFC> IETF Rate algorithm Type B
rateAdjAlgo C <this RFC> IETF Rate algorithm Type C
Other values are unassigned, with the upper boundary of Z.
11.2.9. Test Activation PDU Command Response Field Registry
The Test Activation PDU layout (also) contains a cmdResponse field.
The table below defines the assigned decimal values in the registry.
Field Value Reference Change Description
Name Controller
===================================================================
cmdResponse 0 <this RFC> IETF None (used by
client in Request)
cmdResponse 1 <this RFC> IETF Server Acknowledgment
cmdResponse 2 <this RFC> IETF Server indicates an error
Other values are unassigned, with the upper boundary of 255.
12. Acknowledgments
This specification has been edited by Al Morton. Al Morton died
before he was able to finalise this work. As Al can't complete
author tasks during the IETF standardisation process anymore, it was
decided not to keep him as an author in the proper section.
Respecting, that almost all of the content here has been edited or
created by Al, it seems fair not just to give him credit for his
work, but also list him as editor, if this document reaches RFC
status.
Thanks to Lincoln Lavoie, Can Desem, and Greg Mirsky for reviewing
this draft and providing helpful suggestions and areas for further
development. Ken Kerpez and Chen Li have provided helpful reviews.
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 takes on the protocol changes the Brian
suggested.
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13. References
13.1. Normative References
[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>.
[I-D.ietf-ippm-capacity-metric-method]
Morton, A. C., Geib, R., and L. Ciavattone, "Metrics and
Methods for One-Way IP Capacity", Work in Progress,
Internet-Draft, draft-ietf-ippm-capacity-metric-method-12,
9 June 2021, <https://datatracker.ietf.org/doc/html/draft-
ietf-ippm-capacity-metric-method-12>.
[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>.
[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", RFC 2330,
DOI 10.17487/RFC2330, May 1998,
<https://www.rfc-editor.org/info/rfc2330>.
[RFC2681] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip
Delay Metric for IPPM", RFC 2681, DOI 10.17487/RFC2681,
September 1999, <https://www.rfc-editor.org/info/rfc2681>.
[RFC6071] Frankel, S. and S. Krishnan, "IP Security (IPsec) and
Internet Key Exchange (IKE) Document Roadmap", RFC 6071,
DOI 10.17487/RFC6071, February 2011,
<https://www.rfc-editor.org/info/rfc6071>.
[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>.
[RFC6438] Carpenter, B. and S. Amante, "Using the IPv6 Flow Label
for Equal Cost Multipath Routing and Link Aggregation in
Tunnels", RFC 6438, DOI 10.17487/RFC6438, November 2011,
<https://www.rfc-editor.org/info/rfc6438>.
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[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>.
[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>.
[RFC7680] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
Ed., "A One-Way Loss Metric for IP Performance Metrics
(IPPM)", STD 82, RFC 7680, DOI 10.17487/RFC7680, January
2016, <https://www.rfc-editor.org/info/rfc7680>.
[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>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8468] Morton, A., Fabini, J., Elkins, N., Ackermann, M., and V.
Hegde, "IPv4, IPv6, and IPv4-IPv6 Coexistence: Updates for
the IP Performance Metrics (IPPM) Framework", RFC 8468,
DOI 10.17487/RFC8468, November 2018,
<https://www.rfc-editor.org/info/rfc8468>.
[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>.
[RFC9147] Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version
1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022,
<https://www.rfc-editor.org/info/rfc9147>.
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,
<csrc.nist.gov/publications/detail/sp/800-38a/final>.
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[copycat] Edleine, K., Kuhlewind, K., Trammell, B., and B. Donnet,
"copycat: Testing Differential Treatment of New Transport
Protocols in the Wild (ANRW '17)", 15 July 2017,
<https://irtf.org/anrw/2017/anrw17-final5.pdf>.
[LS-SG12-A]
12, I. S., "LS - Harmonization of IP Capacity and Latency
Parameters: Revision of Draft Rec. Y.1540 on IP packet
transfer performance parameters and New Annex A with Lab
Evaluation Plan", May 2019,
<https://datatracker.ietf.org/liaison/1632/>.
[LS-SG12-B]
12, I. S., "LS on harmonization of IP Capacity and Latency
Parameters: Consent of Draft Rec. Y.1540 on IP packet
transfer performance parameters and New Annex A with Lab &
Field Evaluation Plans", March 2019,
<https://datatracker.ietf.org/liaison/1645/>.
[RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544,
DOI 10.17487/RFC2544, March 1999,
<https://www.rfc-editor.org/info/rfc2544>.
[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>.
[RFC3610] Whiting, D., Housley, R., and N. Ferguson, "Counter with
CBC-MAC (CCM)", RFC 3610, DOI 10.17487/RFC3610, September
2003, <https://www.rfc-editor.org/info/rfc3610>.
[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>.
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[RFC6815] Bradner, S., Dubray, K., McQuaid, J., and A. Morton,
"Applicability Statement for RFC 2544: Use on Production
Networks Considered Harmful", RFC 6815,
DOI 10.17487/RFC6815, November 2012,
<https://www.rfc-editor.org/info/rfc6815>.
[RFC7312] Fabini, J. and A. Morton, "Advanced Stream and Sampling
Framework for IP Performance Metrics (IPPM)", RFC 7312,
DOI 10.17487/RFC7312, August 2014,
<https://www.rfc-editor.org/info/rfc7312>.
[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>.
[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>.
[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>.
[RFC8972] Mirsky, G., Min, X., Nydell, H., Foote, R., Masputra, A.,
and E. Ruffini, "Simple Two-Way Active Measurement
Protocol Optional Extensions", RFC 8972,
DOI 10.17487/RFC8972, January 2021,
<https://www.rfc-editor.org/info/rfc8972>.
[TR-471] Morton, A,, Editor., "Broadband Forum TR-471: IP Layer
Capacity Metrics and Measurement, Issue 3", December 2022,
<https://www.broadband-forum.org/technical/download/TR-
471.pdf>.
[udpst] udpst Project Collaborators, "UDP Speed Test Open
Broadband project", December 2020,
<https://github.com/BroadbandForum/obudpst>.
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[Y.1540] Y.1540, I. R., "Internet protocol data communication
service - IP packet transfer and availability performance
parameters", December 2019,
<https://www.itu.int/rec/T-REC-Y.1540-201912-I/en>.
[Y.Sup60] Morton, A., Rapporteur., "Recommendation Y.Sup60, (09/20)
Interpreting ITU-T Y.1540 maximum IP-layer capacity
measurements", 11 September 2020,
<https://www.itu.int/rec/T-REC-Y.Sup60/en>.
Authors' Addresses
Len Ciavattone
AT&T Labs
Middletown, NJ
United States of America
Email: lencia@att.com
Ruediger Geib
Deutsche Telekom
Ida-Rhodes Str. 2
64295 Darmstadt
Germany
Phone: +49 6151 5812747
Email: Ruediger.Geib@telekom.de
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