| Network Working Group | G. Mirsky |
| Internet-Draft | X. Min |
| Updates: 8762 (if approved) | ZTE Corp. |
| Intended status: Standards Track | H. Nydell |
| Expires: December 14, 2020 | Accedian Networks |
| R. Foote | |
| Nokia | |
| A. Masputra | |
| Apple Inc. | |
| E. Ruffini | |
| OutSys | |
| June 12, 2020 |
Simple Two-way Active Measurement Protocol Optional Extensions
draft-ietf-ippm-stamp-option-tlv-05
This document describes optional extensions to Simple Two-way Active Measurement Protocol (STAMP) which enable measurement performance metrics in addition to ones supported by the STAMP base specification. The document also defines a STAMP Test Session Identifier and thus updates RFC 8762.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 14, 2020.
Copyright (c) 2020 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/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
Simple Two-way Active Measurement Protocol (STAMP) [RFC8762] supports the use of optional extensions that use Type-Length-Value (TLV) encoding. Such extensions enhance the STAMP base functions, such as measurement of one-way and round-trip delay, latency, packet loss, and the ability to detect packet duplication and out-of- order delivery of the test packets. This specification defines optional STAMP extensions, their formats, and the theory of operation. Also, a STAMP Test Session Identifier is defined as an update of the base STAMP specification [RFC8762].
STAMP - Simple Two-way Active Measurement Protocol
DSCP - Differentiated Services Code Point
ECN - Explicit Congestion Notification
NTP - Network Time Protocol
PTP - Precision Time Protocol
HMAC Hashed Message Authentication Code
TLV Type-Length-Value
BITS Building Integrated Timing Supply
SSU Synchronization Supply Unit
GPS Global Positioning System
GLONASS Global Orbiting Navigation Satellite System
LORAN-C Long Range Navigation System Version C
MBZ Must Be Zero
CoS Class of Service
PMF Performance Measurement Function
SSID STAMP Session Identifier
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.
STAMP Session-Sender transmits test packets to STAMP Session-Reflector. STAMP Session-Reflector receives Session-Sender's packet and acts according to the configuration and optional control information communicated in the Session-Sender's test packet. STAMP defines two different test packet formats, one for packets transmitted by the STAMP-Session-Sender and one for packets transmitted by the STAMP-Session-Reflector. STAMP supports two modes: unauthenticated and authenticated. Unauthenticated STAMP test packets are compatible on the wire with unauthenticated TWAMP-Test [RFC5357] packet formats.
By default, STAMP uses symmetrical packets, i.e., the size of the packet transmitted by Session-Reflector equals the size of the packet received by the Session-Reflector.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | SSID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
| MBZ (28 octets) |
| |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Value ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: An example of an extended STAMP Session-Sender test packet format in unauthenticated mode
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Error Estimate | SSID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Receive Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Error Estimate | MBZ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ses-Sender TTL | MBZ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Value ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: An example of an extended STAMP Session-Reflector test packet format in unauthenticated mode
A STAMP Session is identified using 4-tuple (source and destination IP addresses, source and destination UDP port numbers). A STAMP Session-Sender MAY generate a locally unique STAMP Session Identifier (SSID). SSID is two octets long non-zero unsigned integer. A Session-Sender MAY use SSID to identify a STAMP test session. If SSID is used, it MUST be present in each test packet of the given test session. In the unauthenticated mode, SSID is located, as displayed in Figure 1. Figure 2.
A STAMP Session-Reflector that does not support this specification, will return the zeroed SSID field in the reflected STAMP test packet. The Session-Sender MUST stop the session if it receives a zeroed SSID field.
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | MBZ (12 octets) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Error Estimate | SSID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ~ | MBZ (68 octets) | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | HMAC (16 octets) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Base STAMP Session-Sender test packet format in authenticated mode
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MBZ (12 octets) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Error Estimate | SSID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MBZ (4 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Receive Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MBZ (8 octets) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MBZ (12 octets) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Error Estimate | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | MBZ (6 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ses-Sender TTL | | +-+-+-+-+-+-+-+-+ + | | | MBZ (15 octets) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HMAC (16 octets) | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Base STAMP Session-Reflector test packet format in authenticated mode
In the authenticated mode, location of SSID field is shown in Figure 3 and Figure 4.
Type-Length-Value (TLV) encoding scheme provides a flexible extension mechanism for optional informational elements. TLV is an optional field in the STAMP test packet. Multiple TLVs MAY be placed in the STAMP test packet. A TLV MAY be enclosed in a TLV. TLVs have the two octets long Type field, two octets long Length field that is equal to the length of the Value field in octets. Type values, see Section 5.1, less than 32768 identify mandatory TLVs that MUST be supported by an implementation. Type values greater than or equal to 32768 identify optional TLVs that SHOULD be ignored if the implementation does not understand or support them. If a Type value for TLV or sub-TLV is in the range for Vendor Private Use, the Length MUST be at least 4, and the first four octets MUST be that vendor's the Structure of Management Information (SMI) Private Enterprise Number, in network octet order. The rest of the Value field is private to the vendor. The following sections describe the use of TLVs for STAMP that extend STAMP capability beyond its base specification.
A STAMP node, whether Session-Sender or Session-Reflector, receiving a test packet MUST determine whether the packet is a base STAMP packet or includes one or more TLVs. The node MUST compare the value in the Length field of the UDP header and the length of the base STAMP test packet in the mode, unauthenticated or authenticated based on the configuration of the particular STAMP test session. If the difference between the two values is larger than the length of UDP header, then the test packet includes one or more STAMP TLVs that immediately follow the base STAMP test packet.
A system that has received a STAMP test packet with extension TLVs MUST validate each TLV:
Detected error events MUST be logged. Note that transmission of ICMP Error messages and logging SHOULD be throttled.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extra Padding Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Extra Padding ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Extra Padding TLV
The Extra Padding TLV is similar to the Packet Padding field in TWAMP-Test packet [RFC5357]. The Extra Padding TLV MUST be used to create STAMP test packets of larger size that the base STAMP packet [RFC8762]. The length of the base STAMP is 44 octets in the unauthenticated mode or 112 octets in the authenticated mode. The Extra Padding TLV MUST be the last TLV in a STAMP test packet.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Location Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source MAC |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Destination IP Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Source IP Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Port | Source Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Session-Reflector Location TLV
STAMP Session-Sender MAY include the Location TLV to request information from the Session-Reflector. The Session-Sender SHOULD NOT fill any information fields except for Type and Length. The Session-Reflector MUST validate the Length value against the address family of the transport encapsulating the STAMP test packet. If the Length field's value is invalid, the Session-Reflector MUST zero all fields and MUST NOT return any information to the Session-Sender. The Session-Reflector MUST ignore all other fields of the received Location TLV.
The Location TLV MAY be used to determine the last-hop addressing for STAMP packets including source and destination IP addresses as well as the MAC address of the last-hop router. Last-hop MAC address MAY be monitored by the Session-Sender whether there has been a path switch on the last hop, closest to the Session-Reflector. The IP addresses and UDP port will indicate if there is a NAT router on the path, and allows the Session-Sender to identify the IP address of the Session-Reflector behind the NAT, detect changes in the NAT mapping that could cause sending the STAMP packets to the wrong Session-Reflector.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp Information Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sync. Src In | Timestamp In | Sync. Src Out | Timestamp Out |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Timestamp Information TLV
STAMP Session-Sender MAY include the Timestamp Information TLV to request information from the Session-Reflector. The Session-Sender SHOULD NOT fill any information fields except for Type and Length. The Session-Reflector MUST validate the Length value of the STAMP test packet. If the value of the Length field is invalid, the Session-Reflector MUST zero all fields and MUST NOT return any information to the Session-Sender.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Class of Service Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DSCP1 | DSCP2 |ECN| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Class of Service TLV
The STAMP Session-Sender MAY include Class of Service (CoS) TLV in the STAMP test packet. If the CoS TLV is present in the STAMP test packet and the value of the DSCP1 field is zero, then the STAMP Session-Reflector MUST copy the values of Differentiated Services Code Point (DSCP) ECN fields from the received STAMP test packet into DSCP2 and ECN fields respectively of the CoS TLV of the reflected STAMP test packet. If the value of the DSCP1 field is non-zero, then the STAMP Session-Reflector MUST use DSCP1 value from the CoS TLV in the received STAMP test packet as DSCP value of STAMP reflected test packet and MUST copy DSCP and ECN values of the received STAMP test packet into DSCP2 and ECN fields of Class of Service TLV in the STAMP reflected a packet. Upon receiving the reflected packet, the Session-Sender,will save the DSCP and ECN values for analysis of the CoS in the reverse direction.
A STAMP Session-Sender that includes the CoS TLV sets the value of the DSCP1 field and zeroes the value of the DSCP2 field. A STAMP Session-Reflector that received the test packet with the CoS TLV MUST include the CoS TLV in the reflected test packet. Also, the Session-Reflector MUST copy the value of the DSCP field of the IP header of the received STAMP test packet into the DSCP2 field in the reflected test packet. At last, the Session-Reflector MUST set the value of DSCP field's value in the IP header of the reflected test packet equal to the value of the DSCP1 field of the received test packet.
Re-mapping of CoS in some use cases, for example, in mobile backhaul networks is used to provide multiple services, i.e., 2G, 3G, LTE, over the same network. But if it is misconfigured, then it is often difficult to diagnose the root cause of the problem that is viewed as an excessive packet drop of higher-level service while packet drop for lower service packets is at a normal level. Using CoS TLV in STAMP test helps to troubleshoot the existing problem and also verify whether DiffServ policies are processing CoS as required by the configuration.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Direct Measurement Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Sender Tx counter (S_TxC) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Reflector Rx counter (R_RxC) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Reflector Tx counter (R_TxC) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Direct Measurement TLV
The Direct Measurement TLV enables collection of "in profile" IP packets that had been transmitted and received by the Session-Sender and Session-Reflector respectfully. The definition of "in-profile packet" is outside the scope of this document and is left to the test operators to determine.
A STAMP Session-Sender MAY include Access Report TLV (Figure 10) to indicate changes to the access network status to the Session-Reflector. The definition of an access network is outside the scope of this document.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Report Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ID | Resv | Return Code | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Access Report TLV
All other values are invalid and the TLV that contains it MUST be discarded.
The STAMP Session-Sender that includes the Access Report TLV sets the value of the Access ID field according to the type of access network it reports on. Also, the Session-Sender sets the value of the Return Code field to reflect the operational state of the access network. The mechanism to determine the state of the access network is outside the scope of this specification. A STAMP Session-Reflector that received the test packet with the Access Report TLV MUST include the Access Report TLV in the reflected test packet. The Session- Reflector MUST set the value of the Access ID and Return Code fields equal to the values of the corresponding fields from the test packet it has received.
The Session-Sender MUST also arm a retransmission timer after sending a test packet that includes the Access Report TLV. This timer MUST be disarmed upon the reception of the reflected STAMP test packet that includes Access Report TLV. In the event the timer expires before such a packet is received, the Session-Sender MUST retransmit the STAMP test packet that contains the Access Report TLV. This retransmission SHOULD be repeated up to four times before the procedure is aborted. Setting the value for the retransmission timer is based on local policies, network environment. The default value of the retransmission timer for Access Report TLV SHOULD be three seconds. An implementation MUST provide control of the retransmission timer value and the number of retransmissions.
The Access Report TLV is used by the Performance Measurement Function (PMF) components of the Access Steering, Switching and Splitting feature for 5G networks [TS23501]. The PMF component in the User Equipment acts as the STAMP Session-Sender, and the PMF component in the User Plane Function acts as the STAMP Session-Reflector.
A Session-Reflector might be able to put in the Timestamp field only an "SW Local" (see Table 6) timestamp. But the hosting system might provide the timestamp closer to the start of the actual packet transmission even though when it is not possible to deliver the information to the Session-Sender in the packet itself. This timestamp might nevertheless be important for the Session-Sender, as it improves the accuracy of measuring network delay by minimizing the impact of egress queuing delays on the measurement.
A STAMP Session-Sender MAY include the Follow-up Telemetry TLV to request information from the Session-Reflector. The Session-Sender MUST set the Follow-up Telemetry Type and Length fields to their appropriate values. Sequence Number and Timestamp fields MUST be zeroed on transmission by the Session-Sender and ignored by the Session-Reflector upon receipt of the STAMP test packet that includes the Follow-up Telemetry TLV. The Session-Reflector MUST validate the Length value of the STAMP test packet. If the value of the Length field is invalid, the Session-Reflector MUST zero Sequence Number and Timestamp fields. If the Session-Reflector is in stateless mode (defined in Section 4.2 [RFC8762]), it MUST zero Sequence Number and Timestamp fields.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Follow-up Telemetry Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Follow-up Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp M | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Follow-up Telemetry TLV
The STAMP authenticated mode protects the integrity of data collected in the STAMP base packet. STAMP extensions are designed to provide valuable information about the condition of a network, and protecting the integrity of that data is also essential. The keyed Hashed Message Authentication Code (HMAC) TLV MUST be included in a STAMP test packet in the authenticated mode, excluding when the only TLV present is Extra Padding TLV. The HMAC TLV MUST follow all TLVs included in a STAMP test packet, except for the Extra Padding TLV. The HMAC TLV MAY be used to protect the integrity of STAMP extensions in STAMP unauthenticated mode.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HMAC Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| HMAC |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: HMAC TLV
As defined in [RFC8762], STAMP uses HMAC-SHA-256 truncated to 128 bits ([RFC4868]). All considerations regarding using the key and key distribution and management listed in Section 4.4 of [RFC8762] are fully applicable to the use of the HMAC TLV. HMAC is calculated as defined in [RFC2104] over text as the concatenation of all preceding TLVs. The digest then MUST be truncated to 128 bits and written into the HMAC field. In the authenticated mode, HMAC MUST be verified before using any data in the included STAMP TLVs. If HMAC verification by the Session-Reflector fails, then an ICMP Parameter Problem message MUST be generated (with consideration of limiting the rate of error messages). The Code value MUST be set to 0 and the Pointer identifying HMAC Type. Also, both Session-Sender and Session-Reflector SHOULD log the notification that HMAC verification of STAMP TLVs failed. The packet that failed HMAC verification MUST be dropped.
IANA is requested to create the STAMP TLV Type registry. All code points in the range 1 through 32759 in this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC8126]. Code points in the range 32760 through 65279 in this registry shall be allocated according to the "First Come First Served" procedure as specified in [RFC8126]. Remaining code points are allocated according to Table 1:
| Value | Description | Reference |
|---|---|---|
| 0 | Reserved | This document |
| 1- 32767 | Mandatory TLV, unassigned | IETF Review |
| 32768 - 65279 | Optional TLV, unassigned | First Come First Served |
| 65280 - 65519 | Experimental | This document |
| 65520 - 65534 | Private Use | This document |
| 65535 | Reserved | This document |
This document defines the following new values in the Mandatory TLV range of the STAMP TLV Type registry:
| Value | Description | Reference |
|---|---|---|
| TBA1 | Extra Padding | This document |
| TBA2 | Location | This document |
| TBA3 | Timestamp Information | This document |
| TBA4 | Class of Service | This document |
| TBA5 | Direct Measurement | This document |
| TBA6 | Access Report | This document |
| TBA7 | Follow-up Telemetry | This document |
| TBA8 | HMAC | This document |
IANA is requested to create Synchronization Source sub-registry as part of the STAMP TLV Type registry. All code points in the range 1 through 127 in this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC8126]. Code points in the range 128 through 239 in this registry shall be allocated according to the "First Come First Served" procedure as specified in [RFC8126]. Remaining code points are allocated according to Table 1:
| Value | Description | Reference |
|---|---|---|
| 0 | Reserved | This document |
| 1- 127 | Unassigned | IETF Review |
| 128 - 239 | Unassigned | First Come First Served |
| 240 - 249 | Experimental | This document |
| 250 - 254 | Private Use | This document |
| 255 | Reserved | This document |
This document defines the following new values in the Synchronization Source sub-registry:
| Value | Description | Reference |
|---|---|---|
| 1 | NTP | This document |
| 2 | PTP | This document |
| 3 | SSU/BITS | This document |
| 4 | GPS/GLONASS/LORAN-C | This document |
| 5 | Local free-running | This document |
IANA is requested to create Timestamping Method sub-registry as part of the STAMP TLV Type registry. All code points in the range 1 through 127 in this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC8126]. Code points in the range 128 through 239 in this registry shall be allocated according to the "First Come First Served" procedure as specified in [RFC8126]. Remaining code points are allocated according to Table 1:
| Value | Description | Reference |
|---|---|---|
| 0 | Reserved | This document |
| 1- 127 | Unassigned | IETF Review |
| 128 - 239 | Unassigned | First Come First Served |
| 240 - 249 | Experimental | This document |
| 250 - 254 | Private Use | This document |
| 255 | Reserved | This document |
This document defines the following new values in the Timestamping Methods sub-registry:
| Value | Description | Reference |
|---|---|---|
| 1 | HW Assist | This document |
| 2 | SW local | This document |
| 3 | Control plane | This document |
IANA is requested to create Return Code sub-registry as part of STAMP TLV Type registry. All code points in the range 1 through 127 in this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC8126]. Code points in the range 128 through 239 in this registry shall be allocated according to the "First Come First Served" procedure as specified in [RFC8126]. Remaining code points are allocated according to Table 7:
| Value | Description | Reference |
|---|---|---|
| 0 | Reserved | This document |
| 1- 127 | Unassigned | IETF Review |
| 128 - 239 | Unassigned | First Come First Served |
| 240 - 249 | Experimental | This document |
| 250 - 254 | Private Use | This document |
| 255 | Reserved | This document |
This document defines the following new values in the Return Code sub-registry:
| Value | Description | Reference |
|---|---|---|
| 1 | Network available | This document |
| 2 | Network unavailable | This document |
This document defines extensions to STAMP [RFC8762] and inherits all the security considerations applicable to the base protocol. Additionally, the HMAC TLV is defined in this document to protect the integrity of optional STAMP extensions. The use of HMAC TLV is discussed in detail in Section 4.8.
Authors much appreciate the thorough review and thoughtful comments received from Tianran Zhou, Rakesh Gandhi, Yuezhong Song and Yali Wang. Authors express their gratitude to Al Morton for his comments and the most valuable suggestions.
Guo Jun ZTE Corporation 68# Zijinghua Road Nanjing, Jiangsu 210012 P.R.China Phone: +86 18105183663 Email: guo.jun2@zte.com.cn
The following people contributed text to this document:
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
| [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. |
| [RFC8126] | Cotton, M., Leiba, B. and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017. |
| [RFC8174] | Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017. |
| [RFC8762] | Mirsky, G., Jun, G., Nydell, H. and R. Foote, "Simple Two-Way Active Measurement Protocol", RFC 8762, DOI 10.17487/RFC8762, March 2020. |
| [IEEE.1588.2008] | "Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems", IEEE Standard 1588, March 2008. |
| [RFC2104] | Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed-Hashing for Message Authentication", RFC 2104, DOI 10.17487/RFC2104, February 1997. |
| [RFC4868] | Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512 with IPsec", RFC 4868, DOI 10.17487/RFC4868, May 2007. |
| [RFC5905] | Mills, D., Martin, J., Burbank, J. and W. Kasch, "Network Time Protocol Version 4: Protocol and Algorithms Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010. |
| [TS23501] | 3GPP (3rd Generation Partnership Project), "Technical Specification Group Services and System Aspects; System Architecture for the 5G System; Stage 2 (Release 16)", 3GPP TS23501, 2019. |