Network Working Group G. Mirsky
Internet-Draft X. Min
Updates: 8762 (if approved) ZTE Corp.
Intended status: Standards Track H. Nydell
Expires: February 22, 2021 Accedian Networks
R. Foote
Nokia
A. Masputra
Apple Inc.
E. Ruffini
OutSys
August 21, 2020

Simple Two-way Active Measurement Protocol Optional Extensions
draft-ietf-ippm-stamp-option-tlv-09

Abstract

This document describes optional extensions to Simple Two-way Active Measurement Protocol (STAMP) that enable measurement of performance metrics. The document also defines a STAMP Test Session Identifier and thus updates RFC 8762.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute 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 February 22, 2021.

Copyright Notice

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.


Table of Contents

1. Introduction

Simple Two-way Active Measurement Protocol (STAMP) [RFC8762] defined the STAMP base functionalities. This document specifies 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, packet duplication, and out-of-order delivery of 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].

2. Conventions Used in This Document

2.1. Acronyms

BDS BeiDou Navigation Satellite System

BITS Building Integrated Timing Supply

CoS Class of Service

DSCP Differentiated Services Code Point

ECN Explicit Congestion Notification

GLONASS Global Orbiting Navigation Satellite System

GPS Global Positioning System [GPS]

HMAC Hashed Message Authentication Code

LORAN-C Long Range Navigation System Version C

MBZ Must Be Zero

NTP Network Time Protocol [RFC5905]

PMF Performance Measurement Function

PTP Precision Time Protocol [IEEE.1588.2008]

TLV Type-Length-Value

SSID STAMP Session Identifier

SSU Synchronization Supply Unit

STAMP Simple Two-way Active Measurement Protocol

2.2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. STAMP Test Session Identifier

The STAMP Session-Sender transmits test packets to the STAMP Session-Reflector. The STAMP Session-Reflector receives the 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] packets.

By default, STAMP uses symmetrical packets, i.e., the size of the packet transmitted by the 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)                       |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                            TLVs                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 1: The format of an extended STAMP Session-Sender test packet 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                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 ~                            TLVs                               ~
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 2: The format of an extended STAMP Session-Reflector test packet in unauthenticated mode

A STAMP Session is identified by the 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). The SSID is a two-octet-long non-zero unsigned integer. SSID generation policy is implementation-specific. [I-D.gont-numeric-ids-generation] thoroughly analyzes common algorithms for identifier generation and their vulnerabilities. For example, an implementation can use algorithms described in Section 7.1 of [I-D.gont-numeric-ids-generation]. An implementation MUST NOT assign the same identifier to different STAMP test sessions. A Session-Sender MAY use the SSID to identify a STAMP test session. If the SSID is used, it MUST be present in each test packet of the given test session. In the unauthenticated mode, the 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 MAY stop the session if it receives a zeroed SSID field. An implementation of a Session-Sender MUST support control of its behavior in such a scenario. If the test session is not stopped, the Session-Sender, can, for example, send a base STAMP packet [RFC8762] or continue transmitting STAMP test packets with the SSID.

    
  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)                        |
 |                                                               |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 ~                            TLVs                               ~
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  

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)                       |
   |                                                               |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                            TLVs                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  

Figure 4: Base STAMP Session-Reflector test packet format in authenticated mode

Location of the SSID field in the authenticated mode is shown in Figure 3 and Figure 4.

4. TLV Extensions to STAMP

    
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |STAMP TLV Flags|     Type      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                            Value                              ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 5: TLV Format in a STAMP Extended Packet

The 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 a STAMP test packet. Additional TLVs may be enclosed within a given TLV, subject to the semantics of the (outer) TLV in question. TLVs have a one-octet-long STAMP TLV Flags field, a one-octet-long Type field, and a two-octet-long Length field that is equal to the length of the Value field in octets. 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 Structure of Management Information (SMI) Private Enterprise Code, as recorded in IANA's SMI Private Enterprise Codes sub-registry, 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 the STAMP capability beyond its base specification.

All multibyte fields in TLVs defined in this specification are in network byte order.

    
    0 1 2 3 4 5 6 7
   +-+-+-+-+-+-+-+-+
   |U|M|I|R|R|R|R|R|
   +-+-+-+-+-+-+-+-+

Figure 6: STAMP TLV Flags Format

The format of the STAMP TLV Flags displayed in Figure 6 and the location of flags is according to Section 5.2.

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 the UDP header, then the test packet includes one or more STAMP TLVs that immediately follow the base STAMP test packet. A Session-Reflector that does not support STAMP extensions will not process but copy them into the reflected packet, as defined in Section 4.3 [RFC8762]. A Session-Reflector that supports TLVs will indicate specific TLVs that it did not process by setting the U flag to 1 in those TLVs.

A STAMP system, i.e., either a Session-Sender or a Session-Reflector, that has received a STAMP test packet with extension TLVs MUST validate each TLV:

4.1. Extra Padding TLV

    
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |STAMP TLV Flags|Extra Pad Type |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                         Extra Padding                         ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 7: Extra Padding TLV

The Extra Padding TLV is similar to the Packet Padding field in a TWAMP-Test packet [RFC5357]. The use of the Extra Padding TLV is RECOMMENDED to perform a STAMP test using test packets of larger size than the base STAMP packet [RFC8762]. The length of the base STAMP packet is 44 octets in the unauthenticated mode or 112 octets in the authenticated mode. The Extra Padding TLV MAY be present more than one time in an extended STAMP test packet.

4.2. Location TLV

    
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |STAMP TLV Flags| Location Type |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Destination Port       |          Source Port          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                         Sub-TLVs                              ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 8: Location TLV

STAMP Session-Senders MAY include the variable-size Location TLV to query location information from the Session-Reflector. The Session-Sender MUST NOT fill any information fields except for STAMP TLV Flags, Type, and Length. The Session-Reflector MUST verify that the TLV is well-formed. If it is not, the Session-Reflector follows the procedure defined in Section 4 for a malformed TLV.

4.2.1. Location Sub-TLVs

    
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                        EUI-48  Address                        |
   +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                               |            MBZ                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 9: The Value Field of the Source EUI-48 Address sub-TLV

    
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                         IPv4 Address                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   ~                        MBZ (12 octets)                        ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 10: IPv4 Address in a Sub-TLV's Value Field

A sub-TLV in the Location TLV uses the format displayed in Figure 5. Handling of the U and M flags in the sub-TLV is as defined in Section 4. The I flag MUST be set by a Session-Sender and Session-Reflector to 0 before transmission and its value ignored on receipt. The following types of sub-TLV for the Location TLV are defined in this specification (type values are assigned according to Table 5):

4.2.2. Theory of Operation of Location TLV

The Session-Reflector that received an extended STAMP packet with the Location TLV MUST include the Location TLV of the size equal to the size of Location TLV in the received packet in the reflected packet. Based on the local policy, the Session-Reflector MAY leave some fields unreported by filling them with zeroes. An implementation of the stateful Session-Reflector MUST provide control for managing such policies.

A Session-Sender MAY include the Source MAC Address sub-TLV is the Location TLV. If the Session-Reflector receives the Location TLV that includes the Source MAC Address sub-TLV, it MUST include the Source EUI-48 Address sub-TLV if the source MAC address of the received extended test packet is in EUI-48 format. And the Session-Reflector MUST copy the value of the source MAC address in the EUI-48 field. Otherwise, the Session-Reflector MUST use the Source EUI-64 Address sub-TLV and MUST copy the value of the Source MAC address from the received packet into the EUI-64 field. If the received extended STAMP test packet does not have the Source MAC address, the Session-Reflector MUST zero the EUI-64 field before transmitting the reflected packet.

A Session-Sender MAY include the Destination IP Address sub-TLV is the Location TLV. If the Session-Reflector receives the Location TLV that includes the Destination IP Address sub-TLV, it MUST include the Destination IPv4 Address sub-TLV if the source IP address of the received extended test packet is of IPv4 address family. And the Session-Reflector MUST copy the value of the destination IP address in the IPv4 Address field. Otherwise, the Session-Reflector MUST use the Destination IPv6 Address sub-TLV and MUST copy the value of the destination IP address from the received packet into the IPv6 Address field.

A Session-Sender MAY include the Source IP Address sub-TLV is the Location TLV. If the Session-Reflector receives the Location TLV that includes the Source IP Address sub-TLV, it MUST include the Source IPv4 Address sub-TLV if the source IP address of the received extended test packet is of IPv4 address family. And the Session-Reflector MUST copy the value of the source IP address in the IPv4 Address field. Otherwise, the Session-Reflector MUST use the Source IPv6 Address sub-TLV and MUST copy the value of the source IP address from the received packet into the IPv6 Address field.

The Location TLV MAY be used to determine the last-hop IP addresses, ports, and last-hop MAC address for  STAMP packets. The MAC address can indicate a path switch on the last hop. The IP addresses and UDP ports will indicate if there is a NAT router on the path. It allows the Session-Sender to identify the IP address of the Session-Reflector behind the NAT, and detect changes in the NAT mapping that could cause sending the STAMP packets to the wrong Session-Reflector.

4.3. Timestamp Information TLV

    
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |STAMP TLV Flags|Times Info Type|           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Sync. Src In | Timestamp In  | Sync. Src Out | Timestamp Out |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                    Optional sub-TLVs                          ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 11: Timestamp Information TLV

The STAMP Session-Sender MAY include the Timestamp Information TLV to request information from the Session-Reflector. The Session-Sender MUST NOT fill any information fields except for STAMP TLV Flags, Type, and Length. All other fields MUST be filled with zeroes The Session-Reflector MUST validate the Length value of the TLV. If the value of the Length field is invalid, the Session-Reflector follows the procedure defined in Section 4 for a malformed TLV.

4.4. Class of Service TLV

    
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |STAMP TLV Flags|    CoS Type   |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |   DSCP1   |   DSCP2   |ECN|            Reserved               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 12: Class of Service TLV

The STAMP Session-Sender MAY include a Class of Service (CoS) TLV in the STAMP test packet. The format of the CoS TLV is presented in Figure 12.

A STAMP Session-Reflector that receives a 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 and ECN fields of the IP header of the received STAMP test packet into the DSCP2 field in the reflected test packet. Finally, the Session-Reflector MUST set the 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. Upon receiving the reflected packet, the Session-Sender will save the DSCP and ECN values for analysis of the CoS in the reverse direction.

Re-mapping of CoS can be used to provide multiple services (e,g., 2G, 3G, LTE in mobile backhaul networks) over the same network.  But if it is misconfigured, then it is often difficult to diagnose the root cause of excessive packet drops of higher-level service while packet drops for lower service packets are at a normal level.  Using a CoS TLV in STAMP testing helps to troubleshoot the existing problem and also verify whether DiffServ policies are processing CoS as required by the configuration.

4.5. Direct Measurement TLV

    
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |STAMP TLV Flags|  Direct Type  |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              Session-Sender Tx counter  (S_TxC)               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Session-Reflector Rx counter  (R_RxC)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Session-Reflector Tx counter  (R_TxC)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 13: Direct Measurement TLV

The Direct Measurement TLV enables collection of the number of in-profile packets, i.e., packets that form a specific data flow, that had been transmitted and received by the Session-Sender and Session-Reflector, respectively. The definition of "in-profile packet" is outside the scope of this document and is left to the test operators to determine.

A Session-Sender MAY include the Direct Measurement TLV in a STAMP test packet. If the received STAMP test packet includes the Direct Measurement TLV, the Session-Reflector MUST include it in the reflected test packet. The Session-Reflector MUST copy the value from the S_TxC field of the received test packet into the same field of the reflected packet before its transmission.

4.6. Access Report TLV

A STAMP Session-Sender MAY include an Access Report TLV (Figure 14) 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |STAMP TLV Flags|Acc Report Type|           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   ID  |  Resv |  Return Code  |          Reserved             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 14: Access Report TLV

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 reception of the reflected STAMP test packet that includes the 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 and network environment. The default value of the retransmission timer for the 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.

4.7. Follow-up Telemetry TLV

A Session-Reflector might be able to put in the Timestamp field only an "SW Local" (see Table 9) timestamp. But the hosting system might provide a timestamp closer to the start of the actual packet transmission even though it is not possible to deliver the information to the Session-Sender in time for 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. The 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 the Sequence Number and Timestamp fields and set the M flag in the STAMP TLV Flags field in the reflected packet. If the Session-Reflector is in stateless mode (defined in Section 4.2 [RFC8762]), it MUST zero the 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |STAMP TLV Flags| Follow-up Type|           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Sequence Number                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Follow-up Timestamp                      |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Timestamp M  |                     Reserved                  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 15: Follow-up Telemetry TLV

4.8. HMAC 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. All authenticated STAMP base packets (per Section 4.2.2 and Section 4.3.2 [RFC8762]) compatible with this specification MUST additionally authenticate the option TLVs by including the keyed Hashed Message Authentication Code (HMAC) TLV, with the sole exception of when there is only one TLV present, and it is the Extended Padding TLV. The HMAC TLV MUST follow all TLVs included in a STAMP test packet, except for the Extra Padding TLV. If the HMAC TLV appears in any other position in a STAMP extended test packet, then the situation MUST be processed as HMAC verification failure, as defined in this section, further below. The HMAC TLV MAY be used to protect the integrity of STAMP extensions in STAMP unauthenticated mode. An implementation of STAMP extensions MUST provide controls to enable the integrity protection 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |STAMP TLV Flags|   HMAC Type   |             Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                              HMAC                             |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 16: HMAC TLV

As defined in [RFC8762], STAMP uses HMAC-SHA-256 truncated to 128 bits ([RFC4868]). All considerations regarding using the key listed in Section 4.4 of [RFC8762] are fully applicable to the use of the HMAC TLV. Key management and the mechanisms to distribute the HMAC key are outside the scope of this specification. HMAC TLV is anticipated to track updates in the base STAMP protocol [RFC8762], including the use of more advanced cryptographic algorithms. HMAC is calculated as defined in [RFC2104] over text as the concatenation of the Sequence Number field of the base STAMP packet and all preceding TLVs. The digest then MUST be truncated to 128 bits and written into the HMAC field. If the HMAC TLV is present in the extended STAMP test packet, e.g., 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 the Session-Reflector MUST stop processing the received extended STAMP test packet. The Session-Reflector MUST copy the TLVs from the received STAMP test packet into the reflected packet. The Session-Reflector MUST set the I flag in each TLV copied over into the reflected packet to 1 before transmitting the reflected test packet. If the Session-Sender receives the extended STAMP test packet with I flag set to 1, then the Session-Sender MUST stop processing TLVs in the reflected test packet. If HMAC verification by the Session-Sender fails, then the Session-Sender MUST stop processing TLVs in the reflected extended STAMP packet.

5. IANA Considerations

5.1. STAMP TLV Registry

IANA is requested to create the STAMP TLV Type registry. All code points in the range 1 through 175 in this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC8126]. Code points in the range 176 through 239 in this registry shall be allocated according to the "First Come First Served" procedure as specified in [RFC8126]. The remaining code points are allocated according to Table 1:

STAMP TLV Type Registry
Value Description Reference
0 Reserved This document
1- 175 Unassigned This document
176 - 239 Unassigned This document
240 - 251 Experimental This document
252 - 254 Private Use This document
255 Reserved This document

This document defines the following new values in the IETF Review range of the STAMP TLV Type registry:

STAMP TLV Types
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

5.2. STAMP TLV Flags Sub-registry

IANA is requested to create the STAMP TLV Flags sub-registry as part of the STAMP TLV Type registry. The registration procedure is "IETF Review" [RFC8126]. Flags are 8 bits. This document defines the following bit positions in the STAMP TLV Flags sub-registry:

STAMP TLV Flags
Bit position Symbol Description Reference
0 U Unrecognized TLV This document
1 M Malformed TLV This document
2 I Integrity check failed This document

5.3. Sub-TLV Type Sub-registry

IANA is requested to create the sub-TLV Type sub-registry as part of the STAMP TLV Type registry. All code points in the range 1 through 175 in this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC8126]. Code points in the range 176 through 239 in this registry shall be allocated according to the "First Come First Served" procedure as specified in [RFC8126]. The remaining code points are allocated according to Table 4:

Location Sub-TLV Type Sub-registry
Value Description Reference
0 Reserved This document
1- 175 Unassigned This document
176 - 239 Unassigned This document
240 - 251 Experimental This document
252 - 254 Private Use This document
255 Reserved This document

This document defines the following new values in the IETF Review range of the Location sub-TLV Type sub-registry:

STAMP sub-TLV Types
Value Description TLV Used Reference
TBA9 Source MAC Address Location This document
TBA10 Source EUI-48 Address Location This document
TBA11 Source EUI-64 Address Location This document
TBA12 Destination IP Address Location This document
TBA13 Destination IPv4 Address Location This document
TBA14 Destination IPv6 Address Location This document
TBA15 Source IP Address Location This document
TBA16 Source IPv4 Address Location This document
TBA17 Source IPv6 Address Location This document

5.4. Synchronization Source Sub-registry

IANA is requested to create the 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 6:

Synchronization Source Sub-registry
Value Description Reference
0 Reserved This document
1- 127 Unassigned This document
128 - 239 Unassigned This document
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:

Synchronization Sources
Value Description Reference
1 NTP This document
2 PTP This document
3 SSU/BITS This document
4 GPS/GLONASS/LORAN-C/BDS/Galileo This document
5 Local free-running This document

5.5. Timestamping Method Sub-registry

IANA is requested to create the 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 8:

Timestamping Method Sub-registry
Value Description Reference
0 Reserved This document
1- 127 Unassigned This document
128 - 239 Unassigned This document
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:

Timestamping Methods
Value Description Reference
1 HW Assist This document
2 SW local This document
3 Control plane This document

5.6. Return Code Sub-registry

IANA is requested to create the Return Code 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 10:

Return Code Sub-registry
Value Description Reference
0 Reserved This document
1- 127 Unassigned This document
128 - 239 Unassigned This document
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:

Return Codes
Value Description Reference
1 Network available This document
2 Network unavailable This document

6. Security Considerations

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.

To protect against a malformed TLV an implementation of a Session-Sender and Session-Reflector MUST:

Monitoring and optional control of DSCP do not appear to introduce any additional security threat to hosts that communicate with STAMP as defined in [RFC8762]. As this specification defined the mechanism to test DSCP mapping, this document inherits all the security considerations discussed in [RFC2474].

7. Acknowledgments

Authors much appreciate the thorough review and thoughtful comments received from Tianran Zhou, Rakesh Gandhi, Yuezhong Song and Yali Wang. The authors express their gratitude to Al Morton for his comments and the most valuable suggestions. The authors greatly appreciate comments and thoughtful suggestions received from Martin Duke.

8. Contributors

    
   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:

9. References

9.1. Normative References

[RFC2104] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed-Hashing for Message Authentication", RFC 2104, DOI 10.17487/RFC2104, February 1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[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.

9.2. Informative References

[GPS] "Global Positioning System (GPS) Standard Positioning Service (SPS) Performance Standard", GPS SPS 5th Edition, April 2020.
[I-D.gont-numeric-ids-generation] Gont, F. and I. Arce, "On the Generation of Transient Numeric Identifiers", Internet-Draft draft-gont-numeric-ids-generation-04, July 2019.
[IEEE.1588.2008] "Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems", IEEE Standard 1588, March 2008.
[RFC2474] Nichols, K., Blake, S., Baker, F. and D. Black, "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474, DOI 10.17487/RFC2474, December 1998.
[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.
[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.
[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.

Authors' Addresses

Greg Mirsky ZTE Corp. EMail: gregimirsky@gmail.com
Xiao Min ZTE Corp. EMail: xiao.min2@zte.com.cn
Henrik Nydell Accedian Networks EMail: hnydell@accedian.com
Richard Foote Nokia EMail: footer.foote@nokia.com
Adi Masputra Apple Inc. One Apple Park Way Cupertino, CA 95014 USA EMail: adi@apple.com
Ernesto Ruffini OutSys via Caracciolo, 65 Milano, 20155 Italy EMail: eruffini@outsys.org