Network Working Group G. Mirsky Internet-Draft Ericsson Intended status: Standards Track E. Ruffini Expires: 1 November 2025 OutSys H. Nydell Cisco Systems R. Foote Nokia W. Hawkins University of Cincinnati 30 April 2025 Performance Measurement with Asymmetrical Traffic Using STAMP draft-ietf-ippm-asymmetrical-pkts-06 Abstract This document describes an optional extension to a Simple Two-way Active Measurement Protocol (STAMP) that enables control of the length and/or number of reflected packets during a single STAMP test session. In some use cases, the use of asymmetrical test packets allow for the creation of more realistic flows of test packets and, thus, a closer approximation between active performance measurements and conditions experienced by the monitored application. Also, the document includes an analysis of challenges related to performance monitoring in a multicast network. It defines procedures and STAMP extensions to achieve more efficient measurements with a lesser impact on a network. 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 1 November 2025. Mirsky, et al. Expires 1 November 2025 [Page 1] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 Copyright Notice Copyright (c) 2025 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Reflected Test Packet Control TLV . . . . . . . . . . . . . . 3 2.1. Address Group Sub-TLVs . . . . . . . . . . . . . . . . . 6 2.1.1. Layer 2 Address Group Sub-TLV . . . . . . . . . . . . 6 2.1.2. Layer 3 Address Group Sub-TLV . . . . . . . . . . . . 7 3. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 8 3.1. Rate Measurement . . . . . . . . . . . . . . . . . . . . 8 3.1.1. Operational Considerations for Performing Rate Measurement . . . . . . . . . . . . . . . . . . . . . 8 3.2. Active Performance Measurement in Multicast Environment . . . . . . . . . . . . . . . . . . . . . . . 8 3.3. Using Reflected Test Packet Control TLV in Combination with Other TLVs . . . . . . . . . . . . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 10 5. Implementation Status . . . . . . . . . . . . . . . . . . . . 11 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 7.1. Reflected Test Packet Control TLV Type . . . . . . . . . 13 7.2. Conformant Reflected Packet STAMP TLV Flag . . . . . . . 13 7.3. Layer 2 and Layer 3 Address Group Sub-TLV Types . . . . . 14 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 8.1. Normative References . . . . . . . . . . . . . . . . . . 14 8.2. Informative References . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 Mirsky, et al. Expires 1 November 2025 [Page 2] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 1. Introduction Simple Two-way Active Measurement Protocol (STAMP) [RFC8762] defined the STAMP base functionalities. STAMP Protocol Optional Extensions [RFC8972] introduces a TLV structure that allows the Session-Sender to include optional instructions for Session-Reflector. New STAMP TLVs can be defined to support the scenarios in [RFC7497], which discusses the coordination of messaging between the source and destination to help deliver one of the fundamental principles of IP performance metric measurements, minimizing the test traffic effect on user flows. In some scenarios, e.g., rate measurements discussed in [RFC7497], it is beneficial not only to use a variable size of the test packets transmitted downstream while controlling length, number, and interpacket interval for reflected test packets. Measurement of performance metrics in a multicast network using an active measurement method has specific challenges compared to what operators experience monitoring in a unicast network. This document analyzes these challenges, and defines procedures and STAMP extensions to achieve more efficient measurements with a lesser impact on a network. 1.1. Abbreviations STAMP Simple Two-way Active Measurement Protocol DoS Denial-of-Service 1.2. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2. Reflected Test Packet Control TLV This document defines a new optional STAMP extension, Reflected Test Packet Control TLV. The format of the Reflected Test Packet Control TLV is presented in Figure 1. Mirsky, et al. Expires 1 November 2025 [Page 3] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Length of the Reflected Packet |Number of the Reflected Packets| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Interval Between the Reflected Packets | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Sub-TLVs ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Reflected Test Packet Control TLV Format The interpretation of the fields is as follows: STAMP TLV Flags is a one-octet field. Type is a one-octet field that identifies the Reflected Test Packet Control TLV. IANA is requested (Section 7.1) to assign (TBA1) value. Length is a two-octet field. The value is variable, not smaller than 12 octets. Length of the Reflected Packet is a two-octet field. The value is an unsigned integer that is the requested length of a reflected test packet in octets. Number of the Reflected Packets is a two-octet field. The value is an unsigned integer that is the number of reflected test packets the Session-Reflector is requested to transmit in response to receiving a STAMP test packet with the Reflected Test Packet Control TLV. Interval Between the Reflected Packets is a four-octet field. The value is an unsigned integer set to the interval in nanoseconds between the transmission of the consecutive reflected test packets in response to receiving a STAMP test packet with the Reflected Test Packet Control TLV. Sub-TLVs - an optional field that includes additional information communicated by a Session-Sender. Mirsky, et al. Expires 1 November 2025 [Page 4] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 Also, a new STAMP TLV flag [RFC8972], Conformant Reflected Packet allocated by IANA from "STAMP TLV Flags" subregistry (Section 7.2) one-bit C flag (TBA4). A Session-Sender MUST zero this flag on transmission, and the Session-Reflector MUST ignore its value on the receipt of a STAMP test packet with a STAMP TLV. A Session-Sender MAY include the Reflected Test Packet Control TLV in a STAMP test packet. If the received STAMP test packet includes the Reflected Test Packet Control TLV, the Session-Reflector MUST transmit a sequence of reflected test packets according to the following rules: The length of the reflected test packet MUST be the largest of the: a. The length of a base Session-Reflector packet in the mode (unauthenticated or authenticated) of the received STAMP test packet, as defined in Section 4.3 of [RFC8762], including all STAMP extension TLVs [RFC8972], present in the received STAMP test packet but excluding any Extra Padding TLVs. The rationale to exclude any Extra Padding TLV present in combination with Reflected Test Packet Control TLV is to support a scenario when a Session-Reflector is requested to transmit a sequence of packets shorter than the received STAMP packet. b. The value in the Length of the Reflected Packet field of the Reflected Test Packet Control TLV aligned at a four-octet boundary. In such a case where the length of the reflected packet calculated by this rule is longer than the length of the reflected packet calculated by the rules in [RFC8972], the Session-Reflector MUST use the Extra Padding TLV (Section 4.1 of [RFC8972]) to increase the length of the reflected test packet. If the calculated length of the reflected packet exceeds the maximum transmission unit of the interface to reach the Session-Sender, the Session-Reflector MUST set the C (Conformant Reflected Packet) STAMP TLV flag Section 7.2 to 1, and MUST transmit a single reflected packet. Otherwise, the Session- Reflector MUST set the C flag to 0 in each reflected test packet. The number of reflected test packets in the sequence MUST equal the value of the Number of the Reflected Test Packets. If the value of the Number of the Reflected Packets is larger than one, the interval between the transmission of two consecutive reflected packets in the sequence MUST be equal to the value in the Interval Between the Reflected Packets in nanoseconds. To reduce the risk of creating unacceptable levels of congestion in the network that carries the reflected packets, an implementation Mirsky, et al. Expires 1 November 2025 [Page 5] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 of a Session-Reflector that supports the Reflected Test Control TLV MUST provide a limit on the data rate (bytes per second) and the data volume (total bytes) that would be generated in response to an incoming test packet. If a test packet is received that would generate traffic that exceeds either of these limits, the Session-Reflector MUST set the U flag [RFC8972] to 1, and MUST transmit a single reflected packet. Otherwise, the Session- Reflector MUST set the U flag to 0 in each reflected test packet. If the value of the Number of the Reflected Packets equals zero, then the Session-Reflector MUST NOT send a reflected packet. Processing of the received STAMP test packet with the Reflected Test Packet Control TLV, in which the value of the Number of the Reflected Packets equals zero, is according to the local nodal policy. The received STAMP test packet is discarded if no policy to handle these cases is configured on the node. Each reflected test packet in the sequence is formed according to Section 4.3 of [RFC8762]. 2.1. Address Group Sub-TLVs 2.1.1. Layer 2 Address Group Sub-TLV Layer 2 Address Group sub-TLV: A 16-octet sub-TLV that includes the EUI-48 Address Group Mask and EUI-48 Address Group. The Type value is TBA2 (Section 7.3). The value of the Length field MUST be equal to 12. The format of Layer 2 Address Group sub-TLV is presented in Figure 2. 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 Group Mask | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| | | EUI-48 Address Group | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Layer 2 Address Group Sub-TLV Format The Value field consists of the following fields: EUI-48 Address Group Mask: A six-octet field that represents the bitmask to be applied to the Session-Reflector MAC Address. Mirsky, et al. Expires 1 November 2025 [Page 6] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 EUI-48 Address Group: A six-octet field that represents the group this TLV is addressed to. If the Session-Reflector applies the EUI-48 Address Group Mask to its MAC Address and the result is different from the EUI-48 Address Group, then the Session- Reflector MUST stop processing the received test packet. 2.1.2. Layer 3 Address Group Sub-TLV Layer 3 Address Group sub-TLV: A variable-length sub-TLV that includes the IP Address Family, IP Network Prefix, and IP Prefix Length. The Type value is TBA3 (Section 7.3). The value of the Length field MUST be equal to 8 if the value of the Address Family family is set to IPv4. The value of the Length field MUST be equal to 20 if the value of the Address Family field is set to IPv6. The format of Layer 3 Address Group sub-TLV is presented in Figure 3. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Address Family| Prefix Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IP Network Prefix ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Layer 3 Address Group Sub-TLV Format The Value field consists of the following fields: Address Family: A one-octet field that indicates the type of IP address contained in the IP Network Prefix field. If that is IPv4 address, then the value MUST be set to 1. For the IPv6 address, the value MUST be set to 2. Other values MUST be considered invalid. Prefix Length: A one-octet unsigned integer field that contains the length, in bits, of the network prefix part of the value in the IP Network Prefix field. Reserved: A two-octet field. The field MUST be zeroed on transmission and ignored on receipt. IP Network Prefix: A variable-length field. Depending on the value of the Address Family field, the field contains either IPv4 or IPv6 address. If the former, the length is four octets; if the latter - 16 octets. Mirsky, et al. Expires 1 November 2025 [Page 7] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 3. Theory of Operation 3.1. Rate Measurement [RFC7497] defines the problem of access rate measurement in access networks. Essential requirements identified for a test protocol are the ability to control packet characteristics on the tested path, such as asymmetric rate and asymmetric packet size. The Reflected Test Packet Control TLV, defined in Section 2, conforms to the requirements for measuring access rate by providing optional controls of the number of reflected test packets, the size of the reflected packet(s), and the time interval, i.e., rate, in transmitting the sequence of the reflected test packets. The access rate metric and method of access rate measurement are out of the scope of this document. The UDP Speed Test ([RFC9097] and [I-D.ietf-ippm-capacity-protocol]) also allows for the measurement of access bandwidth. 3.1.1. Operational Considerations for Performing Rate Measurement General considerations for using a testing protocol for rate measurement are documented in Section 7 of [RFC7497]. These considerations are specific for In-Service and Out-of-Service (using the terminology of [RFC7497]) rate measurement. In the Out-of- Service testing, an operator may use a very high traffic rate and/or volume (i.e., high values for the Length of the Reflected Packet and/ or Number of the Reflected Packets parameters, and/or low values for the Interval Between the Reflected Packets parameter of the Reflected Test Packet Control TLV) to create congestion in the bottleneck. However, when performing In-Service rate testing, an operator may start with a low rate and/or volume and gradually increase them with each transmitted Reflected Test Packet Control TLV. 3.2. Active Performance Measurement in Multicast Environment For performance measurements using STAMP in a multicast environment, a Session-Sender is expected to be the root and Session-Reflectors leaves of the same multicast distribution tree. The mechanism of constructing the multicast tree is outside the scope of this document. According to [RFC8972], a STAMP Session is demultiplexed by a Session-Reflector by the tuple that consists of source and destination IP addresses, source and destination UDP port numbers, or the source IP address and STAMP Session Identifier. That is also the case when monitoring performance of a multicast flow, despite the fact that the destination IP address is a multicast address. Therefore, the behavior of a Session-Reflector upon receiving a STAMP Mirsky, et al. Expires 1 November 2025 [Page 8] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 test packet over a multicast tree is as defined in [RFC8762] and [RFC8972]. The Session-Reflector MUST use the source IP address of the received STAMP test packet as the destination IP address of the reflected test packet, and MUST use one of the IP addresses associated with the node as the source IP address for that packet. The Session-Sender has to pay more attention when sending a multicast STAMP packet. Instead of possibly receiving a reply from a single Session-Reflector, the Session-Sender may now receive multiple replies from multiple counterparts: its STAMP Session has a 1:N relation. Network traffic is another aspect that needs attention: network congestion may happen if a single packet can generate millions of concurrent replies, all directed to the same endpoint. Depending on the multicast-implementation, adding a Reflected Test Packet Control TLV allows Session-Sender to limit the number of replies. If a multicast environment allows selecting Session- Reflectors, this may, for example, be done by Randomly by specifying a Layer 2 Address Group Sub-TLV: for example, setting the EUI-48 Address Group Mask to 0xF and the EUI-48 Address Group to 0x1. As a result, only 1 out of 16 reflectors will reply; Having a specific vendor NIC by specifying a Layer 2 Address Group Sub-TLV with the EUI-48 Address Group Mask set to 0xFFFFFF000000; Belonging to specific IP networks, for example, a subnet dedicated to IPv6 over IPv4 encapsulation by specifying the appropriate Layer 3 Address Group Sub-TLV. Multicast traffic is also intrinsically asymmetrical, and focus on the return path is usually limited. The Length of the Reflected Packet value can be used to ensure the reflected packet transports all the timestamps and requested information, crucial for the underlying measure, but is as short as possible so as not to flood the network with useless data. 3.3. Using Reflected Test Packet Control TLV in Combination with Other TLVs [RFC9503] defines the Return Path TLV that, when used in combination with the Return Address Sub-TLV, allows a Session-Sender to request the reflected packet be sent to a different address from the Session- Sender one. These STAMP extensions could be used in combination with the Reflected Packet Control TLV, defined in this document, to direct the reflected STAMP test packets to a collector of measurement data (according to [RFC7594]) for further processing and network analytics. An example of the use case could be used in the multicast Mirsky, et al. Expires 1 November 2025 [Page 9] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 scenario when, for example, the Session-Sender is close to the actual multicast frames generator (for example, a camera transmitting live video) so that the test packets follow the same path as the video stream packets in one direction. The data center where the test data are analyzed could be far away, and it would be better to have reflected packets return there. For compatibility with [RFC9503], a Session-Sender MUST NOT include a Return Path Control Code Sub-TLV with the Control Code flag set to No Reply Requested in the same test packet as the Reflected Test Packet Control TLV is non-zero. A Session-Reflector that supports both TLVs MUST set the U flag in Return Path and Reflected Test Packet Control TLVs in the reflected STAMP packet. Furthermore, the Session- Reflector SHOULD log a notification to inform an operator about the misconstructed STAMP packet. Reflected Test Packet Control TLV can be combined with the Class of Service TLV [RFC8972] to augment rate testing or testing in a multicast network with monitoring the onsistency of Differentiated Services Code Point and Explicit Congestion Notification values in forward and reverse directions of the particular STAMP test session. 4. Security Considerations Security considerations discussed in [RFC7497], [RFC8762],[RFC8972], and [RFC9503] apply to this document. Furthermore, spoofed STAMP test packets with the Reflected Test Packet Control TLV can be exploited to conduct a Denial-of-Service (DoS) attack. Hence, implementations MUST use an identity protection mechanism. For example, the Session-Reflector could verify the information about the source of the STAMP packet against a pre-defined list of trusted nodes. Furthermore, an implementation that supports this specification MUST provide administrative control of support of the Reflected Test Packet Control TLV on a Session-Reflector with it being disabled by default. Also, either STAMP authentication mode [RFC8762] or HMAC TLV [RFC8972] SHOULD be used for a STAMP test session containing the Reflected Test Packet Control TLV. Furthermore, a DoS attack using the Reflected Test Packet Control TLV might target the STAMP Session-Reflector by overloading it with test packet reflection, e.g., extremely small intervals and/or too many concurrent test sessions. To mitigate that, a Session-Reflector implementation that supports the new TLV MUST provide a mechanism to limit the reflection rate and volume of STAMP test packets (see Section 2 for detailed discussion). Mirsky, et al. Expires 1 November 2025 [Page 10] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 Considering the potential number of reflected packets generated by a single test packet sent to a multicast address, parameters in the first STAMP test packet with the Reflected Test Packet Control TLV MUST be selected conservatively. Consider the Number of the Reflected Packets field value set to one. As a result, a Session- Sender, by counting the packets reflected after originating a first STAMP test packet with the Reflected Test Packet Control TLV, can evaluate the load caused by using the Reflected Test Packet Control TLV in which more than a single reflected packet to the same multicast destination is requested. To mitigate the risk of using the Reflected Test Packet Control TLV in a multicast network further, a Session-Sender SHOULD sign packets using the HMAC TLV when sending such messages in unauthenticated mode [RFC8762]. But even with the HMAC TLV, the Reflected Test Packet Control TLV could be exploited by a replay attack. To mitigate that risk, a STAMP Session-Reflector SHOULD use the value of the Sequence Number field [RFC8762] of the received STAMP test packet. If that value compared to the received in the previous test packet of the same STAMP test session is not increasing, then the Session-Reflector MUST respond with a single reflected packet, setting the U flag to 1 [RFC8972]. A Session-Sender SHOULD NOT send the next STAMP test packet with the Reflected Test Packet Control TLV before the Session-Reflector is expected to complete transmitting all reflected packets in response to the Reflected Test Packet Control TLV in the previous test packet. In some scenarios the Reflected Test Packet Control TLV might induce congestion on the transient bottleneck. Section 10 of [RFC9097] specifies security requirements for capacity measurements with asymmetric UDP loads. When planning In-Service capacity measurement operators SHOULD follow recommendations formulated in Section 7 of [RFC7497]. Section 3.1.5 of [RFC8085] determines that a UDP congestion control SHOULD respond quickly to experienced congestion and account for loss rate and response time when choosing a new rate. Appendix A of [RFC9097] offers an example pseudo-code for a UDP load rate adjustment algorithm with congestion control. 5. Implementation Status Note to RFC Editor: This section MUST be removed before publication of the document. This section records the status of known implementations of the protocol defined by this specification at the time of posting of this Internet-Draft, and is based on a proposal described in [RFC7942]. The description of implementations in this section is intended to assist the IETF in its decision processes in progressing drafts to RFCs. Please note that the listing of any individual implementation here does not imply endorsement by the IETF. Furthermore, no effort Mirsky, et al. Expires 1 November 2025 [Page 11] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 has been spent to verify the information presented here that was supplied by IETF contributors. This is not intended as, and must not be construed to be, a catalog of available implementations or their features. Readers are advised to note that other implementations may exist. According to [RFC7942], "this will allow reviewers and working groups to assign due consideration to documents that have the benefit of running code, which may serve as evidence of valuable experimentation and feedback that have made the implemented protocols more mature. It is up to the individual working groups to use this information as they see fit". - The organization responsible for the implementation: Will Hawkins (Individual). - The implementation's name: Teaparty. - A brief general description: Teaparty is an open source implementation of the Simple Two-Way Active Measurement Protocol and many of the optional extensions. The implementation can function as a Session Sender and Session Reflector. It contains support for Authenticated and Unauthenticated modes. It also contains an implementation of a STAMP dissector for Wireshark. - The implementation's level of maturity: Interoperable with Junos OS Evolved STAMP/TWAMP-Light implementations (https://www.juniper.net/do cumentation/us/en/software/junos/standards/topics/concept/rpm.html), Nokia's TWAMP Light implementation (https://github.com/nokia/twampy), and Cujo's TWAMP Light implementation (https://github.com/getCUJO/ twamp-light). - Coverage: Includes support for: * Authenticated and Unauthenticated modes * Stateless and stateful operation * 9 standardized and to-be standardized extensions - Version compatibility: N/A - Licensing: GPLv3. - Implementation experience: Incorporating the Reflected Packet Control TLV into the Teaparty implementation was no challenge from the protocol perspective (because the specification is well written and the authors were responsive to requests for clarification) but Mirsky, et al. Expires 1 November 2025 [Page 12] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 did require enhancements to the underlying mechanics. No extensions (or components of the base functionality) before the Reflected Packet Control TLV required support for the Session Reflector to generate ongoing responses to a test packet from a Session Sender. As a result, all responses were generated and sent upon receipt of a test packet with no further processing. The functionality required to implement the Reflected Packet Control TLV was already on the list of upcoming additions to Teaparty, whether this extension was proposed or not (a complete implementation of the Access Report extension requires such support). Overall, implementation was straightforward. - Contact information: Source code is available at https://github.com/cerfcast/teaparty. Author is available at https://datatracker.ietf.org/person/hawkinsw@obs.cr - The date when information about this particular implementation was last updated: April 28, 2025 6. Acknowledgments The authors thank Zhang Li, Ruediger Geib, Rakesh Gandhi, Giuseppe Fiocolla, and Greg White for their thorough reviews and helpful suggestions, which improved the document. 7. IANA Considerations 7.1. Reflected Test Packet Control TLV Type The IANA is requested to assign a new value for the Reflected Test Packet Control TLV from the STAMP TLV Types registry according to Table 1. +=======+===============================+===============+ | Value | Description | Reference | +=======+===============================+===============+ | TBA1 | Reflected Test Packet Control | This document | +-------+-------------------------------+---------------+ Table 1: New Reflected Test Packet Control Type TLV 7.2. Conformant Reflected Packet STAMP TLV Flag IANA is requested to allocate a bit position for the Conformant Reflected Packet flag from the "STAMP TLV Flags" subregistry according to Table 2. Mirsky, et al. Expires 1 November 2025 [Page 13] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 +==============+========+=============+===============+ | Bit position | Symbol | Description | Reference | +==============+========+=============+===============+ | TBA4 | C | Conformance | This document | +--------------+--------+-------------+---------------+ Table 2: Conformant Reflected Packet STAMP TLV Flag 7.3. Layer 2 and Layer 3 Address Group Sub-TLV Types The IANA is requested to assign new values for the Layer 2 and Layer 3 Address Group sub-TLV Types from the STAMP Sub-TLV Types registry according to Table 3. +=======+=======================+================+===============+ | Value | Description | TLV Used | Reference | +=======+=======================+================+===============+ | TBA2 | Layer 2 Address Group | Reflected Test | This document | | | | Packet Control | | +-------+-----------------------+----------------+---------------+ | TBA3 | Layer 3 Address Group | Reflected Test | This document | | | | Packet Control | | +-------+-----------------------+----------------+---------------+ Table 3: STAMP sub-TLV Types for the Reflected Test Packet Control TLV 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC7497] Morton, A., "Rate Measurement Test Protocol Problem Statement and Requirements", RFC 7497, DOI 10.17487/RFC7497, April 2015, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Mirsky, et al. Expires 1 November 2025 [Page 14] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 [RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple Two-Way Active Measurement Protocol", RFC 8762, DOI 10.17487/RFC8762, March 2020, . [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, . [RFC9503] Gandhi, R., Ed., Filsfils, C., Chen, M., Janssens, B., and R. Foote, "Simple Two-Way Active Measurement Protocol (STAMP) Extensions for Segment Routing Networks", RFC 9503, DOI 10.17487/RFC9503, October 2023, . 8.2. Informative References [I-D.ietf-ippm-capacity-protocol] Ciavattone, L. and R. Geib, "Test Protocol for One-way IP Capacity Measurement", Work in Progress, Internet-Draft, draft-ietf-ippm-capacity-protocol-15, 30 April 2025, . [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, . [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running Code: The Implementation Status Section", BCP 205, RFC 7942, DOI 10.17487/RFC7942, July 2016, . [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, March 2017, . [RFC9097] Morton, A., Geib, R., and L. Ciavattone, "Metrics and Methods for One-Way IP Capacity", RFC 9097, DOI 10.17487/RFC9097, November 2021, . Authors' Addresses Mirsky, et al. Expires 1 November 2025 [Page 15] Internet-Draft Asymmetrical Traffic Using STAMP April 2025 Greg Mirsky Ericsson Email: gregimirsky@gmail.com Ernesto Ruffini OutSys Email: eruffini@outsys.org Henrik Nydell Cisco Systems Email: hnydell@cisco.com Richard Foote Nokia Email: footer.foote@nokia.com Will Hawkins University of Cincinnati Email: hawkinsw@obs.cr Mirsky, et al. Expires 1 November 2025 [Page 16]