SPRING Working Group R. Gandhi, Ed. Internet-Draft C. Filsfils Intended Status: Standards Track S. Soni Expires: December 11, 2018 Cisco Systems, Inc. D. Voyer Bell Canada S. Salsano Universita di Roma "Tor Vergata" P. L. Ventre CNIT June 9, 2018 UDP Path for In-band Performance Measurement for Segment Routing Networks draft-gandhi-spring-udp-pm-01 Abstract Segment Routing (SR) is applicable to both Multiprotocol Label Switching (SR-MPLS) and IPv6 (SRv6) data planes. This document specifies a procedure for using UDP path for sending and processing in-band probe query and response messages for Performance Measurement (PM). The procedure uses the RFC 6374 defined mechanisms for Delay and Loss performance measurement. The procedure specified is applicable to IPv4, IPv6, SR-MPLS, and SRv6 data planes for both links and end-to-end measurement for SR Policies. This document also defines mechanisms for handling Equal Cost Multipaths (ECMPs) for SR Policies. In addition, this document defines new Return Path Segment List TLV for two-way performance measurement. 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 http://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." Gandhi, et al. Expires December 11, 2018 [Page 1] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 Copyright Notice Copyright (c) 2018 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 (http://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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 4 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4 2.3. Reference Topology . . . . . . . . . . . . . . . . . . . . 5 3. Probe Messages . . . . . . . . . . . . . . . . . . . . . . . . 6 3.1. Probe Query Message . . . . . . . . . . . . . . . . . . . 6 3.1.1. Delay Measurement Probe Query Message . . . . . . . . 6 3.1.2. Loss Measurement Probe Query Message . . . . . . . . . 6 3.1.2.1. Loss Measurement Flags . . . . . . . . . . . . . . 7 3.1.3. In-band Probe Query for SR Links . . . . . . . . . . . 7 3.1.4. In-band Probe Query for End-to-end Measurement of SR Policy . . . . . . . . . . . . . . . . . . . . . . . . 8 3.1.4.1. In-band Probe Query Message for SR-MPLS Policy . . 8 3.1.4.2. In-band Probe Query Message for SRv6 Policy . . . 8 3.2. Probe Response Message . . . . . . . . . . . . . . . . . . 8 3.2.1. One-way Measurement for SR Link and end-to-end SR Policy . . . . . . . . . . . . . . . . . . . . . . . . 10 3.2.1.1. Probe Response Message to Controller . . . . . . . 10 3.2.2. Two-way Measurement for SR Links . . . . . . . . . . . 10 3.2.3. Two-way End-to-end Measurement of SR Policy . . . . . 10 3.2.3.1. Return Path Segment List TLV . . . . . . . . . . . 10 3.2.3.2. In-band Probe Response Message for SR-MPLS Policy . . . . . . . . . . . . . . . . . . . . . . 11 3.2.3.3. In-band Probe Response Message for SRv6 Policy . . 12 3.3. ECMP Support . . . . . . . . . . . . . . . . . . . . . . . 12 3.4. Sequence Number TLV . . . . . . . . . . . . . . . . . . . 13 4. Security Considerations . . . . . . . . . . . . . . . . . . . 14 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Gandhi, et al. Expires December 11, 2018 [Page 2] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 6.1. Normative References . . . . . . . . . . . . . . . . . . . 15 6.2. Informative References . . . . . . . . . . . . . . . . . . 15 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 17 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 1. Introduction Segment Routing (SR) technology greatly simplifies network operations for Software Defined Networks (SDNs). SR is applicable to both Multiprotocol Label Switching (SR-MPLS) and IPv6 (SRv6) data planes. SR takes advantage of the Equal-Cost Multipaths (ECMPs) between source, transit and destination nodes. SR Policies as defined in [I-D.spring-segment-routing-policy] are used to steer traffic through a specific, user-defined path using a stack of Segments. Built-in SR Performance Measurement (PM) is one of the essential requirements to provide Service Level Agreements (SLAs). The One-Way Active Measurement Protocol (OWAMP) defined in [RFC4656] and Two-Way Active Measurement Protocol (TWAMP) defined in [RFC5357] provide capabilities for the measurement of various performance metrics in IP networks. These protocols rely on control channel signaling to establish a connection over an UDP path to bootstrap PM sessions, and they are not compatible with the mechanisms defined in [RFC6374]. These protocols lack support for IEEE 1588 timestamps [IEEE1588] and direct-mode LM, which are required in Segment Routing networks [RFC6374]. [RFC6374] specifies protocol mechanisms to enable the efficient and accurate measurement of performance metrics and can be used in SR networks with MPLS data plane [I-D.spring-sr-mpls-pm]. [RFC6374] addresses the limitations of the IP based performance measurement protocols. However, [RFC6374] requires data plane to support MPLS Generic Associated Channel Label (GAL) and Generic Associated Channel (G-Ach), which may not be supported on all nodes in the network. [RFC7876] specifies the procedures to be used when sending and processing out-of-band performance measurement probe response messages over an UDP return path for RFC 6374 based probe queries. [RFC7876] can be used to send out-of-band PM probe responses in both SR-MPLS and SRv6 networks for one-way performance measurement. For SR Policies, there is a need to measure the performance of all end-to-end forwarding paths due to presence of ECMPs between the source and transit nodes, between transit nodes and between transit and destination nodes. Existing PM protocols (e.g. OWAMP, TWAMP, RFC Gandhi, et al. Expires December 11, 2018 [Page 3] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 6374, etc.) do not define handling for ECMP forwarding paths in SR networks. For two-way measurements for SR Policies, there is a need to specify a return path in the form of a Segment List in PM probe query messages without requiring any SR Policy state on the destination node. Exiting protocols do not have such mechanisms to specify return path in the PM probe query messages. This document specifies a procedure for using UDP path for sending and processing in-band probe query and response messages for Performance Measurement that does not require to bootstrap PM sessions. The procedure uses RFC 6374 defined mechanisms for Delay and Loss PM and unless otherwise specified, the procedures from RFC 6374 are not modified. The procedure specified is applicable to IPv4, IPv6, SR-MPLS and SRv6 data planes. The procedure does not require to bootstrap PM sessions and can be used for both SR links and end-to-end measurement for SR Policies. This document also defines mechanisms for handling Equal Cost Multipaths (ECMPs) for SR Policies. In addition, this document defines Return Path Segment List TLV for two-way performance measurement. 2. Conventions Used in This Document 2.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119] [RFC8174]. 2.2. Abbreviations ACH: Associated Channel Header. BSID: Binding Segment ID. DFLag: Data Format Flag. DM: Delay Measurement. G-ACh: Generic Associated Channel (G-ACh). GAL: Generic Associated Channel (G-ACh) Label. LM: Loss Measurement. MPLS: Multiprotocol Label Switching. Gandhi, et al. Expires December 11, 2018 [Page 4] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 PM: Performance Measurement. PTP: Precision Time Protocol. RPSL: Return Path Segment List. SID: Segment ID. SL: Segment List. SR: Segment Routing. SR-MPLS: Segment Routing with MPLS data plane. SRv6: Segment Routing with IPv6 data plane. URO: UDP Return Object. 2.3. Reference Topology In the reference topology, the querier node R1 initiates a probe query for performance measurement and the responder node R5 sends a probe response for the query message received. The probe response may be sent to the querier node R1 or to a controller node R100. The nodes R1 and R5 may be directly connected via a link enabled with Segment Routing or there exists an SR Policy [I-D.spring-segment-routing-policy] on node R1 with destination to node R5. ------ |R100| ------ ^ | Response (optional) | +-------+ Query +-------+ | | - - - - - - - - - ->| | | R1 |---------------------| R5 | | |<- - - - - - - - - - | | +-------+ Response +-------+ Reference Topology Both Delay and Loss performance measurement is performed in-band for the traffic traversing between node R1 and node R5. One-way delay Gandhi, et al. Expires December 11, 2018 [Page 5] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 and two-way delay measurements are defined in Section 2.4 of [RFC6374]. Transmit and Receive packet loss measurements are defined in Section 2.2 of [RFC6374]. One-way loss measurement provides receive packet loss whereas two-way loss measurement provides both transmit and receive packet loss. 3. Probe Messages 3.1. Probe Query Message In this document, UDP path is defined for sending and processing PM probe query messages for Delay and Loss measurements for SR links and end-to-end SR Policies as described in the following Sections. As well-known UDP port is used for identifying PM probe packets, bootstrapping of the PM session [RFC5357] is not required. 3.1.1. Delay Measurement Probe Query Message The message content for Delay Measurement probe query message using UDP header [RFC768] is shown in Figure 1. As shown, the DM probe query message is sent with Destination UDP port number TBA1 defined in this document. The Source UDP port may optionally be set to TBA1 for two-way delay measurement. The DM probe query message contains the payload for delay measurement defined in Section 3.2 of [RFC6374]. +---------------------------------------------------------------+ | IP Header | . Source IP Address = Querier IPv4 or IPv6 Address . . Destination IP Address = Responder IPv4 or IPv6 Address . . Protocol = UDP . . IP TTL = 1 . . Router Alert Option Not Set . . . +---------------------------------------------------------------+ | UDP Header | . Source Port = As chosen by Querier . . Destination Port = TBA1 by IANA for Delay Measurement . . . +---------------------------------------------------------------+ | Payload = Message as specified in Section 3.2 of RFC 6374 | . . +---------------------------------------------------------------+ Figure 1: DM Probe Query Message 3.1.2. Loss Measurement Probe Query Message Gandhi, et al. Expires December 11, 2018 [Page 6] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 The message content for Loss measurement probe query message using UDP header [RFC768] is shown in Figure 2. As shown, the LM probe query message is sent with Destination UDP port number TBA2 defined in this document. The Source UDP port may optionally be set to TBA2 for two-way loss measurement. The LM probe query message contains the payload for loss measurement defined in Section 3.1 of [RFC6374]. +---------------------------------------------------------------+ | IP Header | . Source IP Address = Querier IPv4 or IPv6 Address . . Destination IP Address = Responder IPv4 or IPv6 Address . . Protocol = UDP . . IP TTL = 1 . . Router Alert Option Not Set . . . +---------------------------------------------------------------+ | UDP Header | . Source Port = As chosen by Querier . . Destination Port = TBA2 by IANA for Loss Measurement . . . +---------------------------------------------------------------+ | Payload = Message as specified in Section 3.1 of RFC 6374 | . . +---------------------------------------------------------------+ Figure 2: LM Probe Query Message 3.1.2.1. Loss Measurement Flags An LM message carries Data Format Flags (DFlags) as defined in [RFC6374]. New Flag is defined in this document for Color (C) in the DFlags field as follows. +-+-+-+-+ |X|B|C|0| +-+-+-+-+ Data Format Flags The Flag C indicates the Color of the counters in the LM probe message [RFC6374] when using Alternate-Marking method defined in [RFC8321]. 3.1.3. In-band Probe Query for SR Links The probe query message defined in Figure 1 is sent in-band for Delay measurement and defined in Figure 2 is used for Loss measurement for SR links. Gandhi, et al. Expires December 11, 2018 [Page 7] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 3.1.4. In-band Probe Query for End-to-end Measurement of SR Policy 3.1.4.1. In-band Probe Query Message for SR-MPLS Policy The message content for in-band probe query message using UDP header for end-to-end performance measurement of SR-MPLS Policy is shown 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List(0) | EXP |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List(n) | EXP |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message as shown in Figure 1 for DM or Figure 2 for LM | . . +---------------------------------------------------------------+ Figure 3: In-band Probe Query Message for SR-MPLS Policy The Segment List (SL) can be empty to indicate Implicit NULL label case. 3.1.4.2. In-band Probe Query Message for SRv6 Policy The in-band probe query messages using UDP header for end-to-end performance measurement of an SRv6 Policy is sent using SRv6 Segment Routing Header (SRH) and Segment List as defined in [I-D.6man-segment-routing-header] and is shown in Figure 4. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SRH | . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message as shown in Figure 1 for DM or Figure 2 for LM | . . +---------------------------------------------------------------+ Figure 4: In-band Probe Query Message for SRv6 Policy 3.2. Probe Response Message Gandhi, et al. Expires December 11, 2018 [Page 8] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 When the received probe query message does not contain any UDP Return Object (URO) TLV [RFC7876], the probe response message uses the IP/UDP information from the probe query message. The content of the probe response message is shown in Figure 5. +---------------------------------------------------------------+ | IP Header | . Source IP Address = Responder IPv4 or IPv6 Address . . Destination IP Address = Source IP Address from Query . . Protocol = UDP . . Router Alert Option Not Set . . . +---------------------------------------------------------------+ | UDP Header | . Source Port = As chosen by Responder . . Destination Port = Source Port from Query . . . +---------------------------------------------------------------+ | Message as specified in RFC 6374 Section 3.2 for DM, or | . Message as specified in RFC 6374 Section 3.1 for LM . . . +---------------------------------------------------------------+ Figure 5: Probe Response Message When the received probe query message contains UDP Return Object (URO) TLV [RFC7876], the probe response message the message uses the IP/UDP information from the URO in the probe query message. The content of the probe response message is shown in Figure 6. +---------------------------------------------------------------+ | IP Header | . Source IP Address = Responder IPv4 or IPv6 Address . . Destination IP Address = URO.Address . . Protocol = UDP . . Router Alert Option Not Set . . . +---------------------------------------------------------------+ | UDP Header | . Source Port = As chosen by Responder . . Destination Port = URO.UDP-Destination-Port . . . +---------------------------------------------------------------+ | Message as specified in RFC 6374 Section 3.2 for DM, or | . Message as specified in RFC 6374 Section 3.1 for LM . . . +---------------------------------------------------------------+ Gandhi, et al. Expires December 11, 2018 [Page 9] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 Figure 6: Probe Response Message Using URO from Probe Query Message 3.2.1. One-way Measurement for SR Link and end-to-end SR Policy For one-way performance measurement, the probe response message as defined in Figure 5 or Figure 6 is sent out-of-band for both SR links and SR Policies. The PM querier node can receive probe response message back by properly setting its own IP address as Source Address of the header or by adding URO TLV in the probe query message and setting its own IP address in the IP Address in the URO TLV (Type=131) [RFC7876]. 3.2.1.1. Probe Response Message to Controller As shown in Reference Topology, if the querier node requires the probe response message to be sent to the controller R100, it adds URO TLV in the probe query message and sets the IP address of R100 in the IP Address field and UDP port TBA1 for DM and TBA2 for LM in the UDP- Destination-Port field of the URO TLV (Type=131) [RFC7876]. 3.2.2. Two-way Measurement for SR Links For two-way performance measurement, when using a bidirectional channel, the probe response message as defined in Figure 5 or Figure 6 is sent back in-band to the querier node for SR links. In this case, the "control code" in the probe query message is set to "in-band response requested" [RFC6374]. 3.2.3. Two-way End-to-end Measurement of SR Policy For two-way performance measurement, when using a bidirectional channel, the probe response message is sent back in-band to the querier node for end-to-end measurement of SR Policies. In this case, the "control code" in the probe query message is set to "in-band response requested" [RFC6374]. 3.2.3.1. Return Path Segment List TLV For two-way performance measurement, the responder node needs to send the probe response message in-band on a specific reverse SR path. This way the destination node does not require any additional SR Policy state. The querier node can request in the probe query message to the responder node to send a response back on a given reverse path (typically co-routed path for two-way measurement). [RFC6374] defines DM and LM probe query messages that can include one or more optional TLVs. New TLV Types are defined in this document Gandhi, et al. Expires December 11, 2018 [Page 10] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 for Return Path Segment List (RPSL) to carry reverse SR path for probe response messages. The format of the RPSL TLV is shown in Figure 7: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RPSL Type | Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List(0) | . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List(n) | . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7: Return Path Segment List TLV All Segments in Segment List can be one of following Types: o RPSL Type (value TBA3) carrying SR-MPLS Labels o RPSL Type (value TBA4) carrying SRv6 Segments o RPSL Type (value TBA5) carrying SR-MPLS Binding SID [I-D.pce-binding-label-sid] of the Reverse SR Policy o RPSL Type (value TBA6) carrying SRv6 Binding SID of the Reverse SR Policy The Segment List(0) can be used by the responder node to compute the next-hop IP address and outgoing interface to send the probe response messages. The RPSL TLV is optional. The PM querier node MUST only insert one RPSL TLV in the probe query message and the responder node MUST only process the first RPSL TLV in the probe query message and ignore other RPSL TLVs if present. The responder node MUST send probe response message back on the reverse path specified in the RPSL TLV and MUST NOT add RPSL TLV in the probe response message. 3.2.3.2. In-band Probe Response Message for SR-MPLS Policy The message content for sending probe response message in-band using Gandhi, et al. Expires December 11, 2018 [Page 11] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 UDP header for two-way end-to-end performance measurement of an SR-MPLS Policy is shown in Figure 8. The SR-MPLS label stack in the packet header is built using the Segment List received in the RPSL TLV in the probe query message. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List(0) | EXP |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List(n) | EXP |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message as shown in Figure 5 or 6 | . IP TTL = 1 . . . +---------------------------------------------------------------+ Figure 8: In-band Probe Response Message for SR-MPLS Policy 3.2.3.3. In-band Probe Response Message for SRv6 Policy The message content for sending probe response message in-band using UDP header for two-way end-to-end performance measurement of an SRv6 Policy is shown in Figure 9. For SRv6 Policy, the SRv6 SID stack in the probe response message SRH is built using the SRv6 Segment List received in the RPSL TLV in the probe query message. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SRH | . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message as shown in Figure 5 or 6 | . IP TTL = 1 . . . +---------------------------------------------------------------+ Figure 9: In-band Probe Response Message for SRv6 Policy 3.3. ECMP Support An SR Policy can have a number of end-to-end forwarding paths due to Gandhi, et al. Expires December 11, 2018 [Page 12] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 presence of Equal Cost Multipaths (ECMPs) between the source and transit nodes, between transit nodes and between transit and destination nodes. The PM probe messages can be sent to traverse different ECMP forwarding paths and measure performance of all end-to-end forwarding paths of an SR Policy. Forwarding planes have various hashing functions available to forward packets on specific ECMP paths. Following mechanisms can be used in PM probe messages to take advantage of the hashing function in forwarding plane to influence the ECMP path taken by them. o For IPv4 and SR-MPLS, the mechanisms described in [RFC8029] for handling ECMPs are also applicable to the performance measurement. For IPv4 and SR-MPLS, in IP/UDP header of the PM probe messages, different Destination Addresses in the range of 127/8 [RFC8029] or different Source Addresses or different Source UDP ports, etc. can be used. o For SR-MPLS, entropy label [RFC6790] in the PM probe messages can be used. o For IPv6, as specified in [RFC6437], 3-tuple of Flow Label, Source Address and Destination Address fields in the IPv6 header of the PM probe messages can be used. o For SRv6, Flow Label in SRH [I-D.6man-segment-routing-header] of the PM probe messages can be used. 3.4. Sequence Number TLV The message formats for DM and LM [RFC6374] do not contain sequence number for probe query packets. Sequence numbers can be useful when some probe query messages are lost or they arrive out of order. [RFC6374] defines DM and LM probe query and response messages that can include one or more optional TLVs. New TLV Type (value TBA7) is defined in this document to carry sequence number for probe query and response messages. The format of the Sequence Number TLV is shown in Figure 10: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type TBA7 | Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | . . Gandhi, et al. Expires December 11, 2018 [Page 13] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 10: Sequence Number TLV The Sequence Number TLV is optional. The PM querier node SHOULD only insert one Sequence Number TLV in the probe query message and the responder node in the probe response message SHOULD return the first Sequence Number TLV from the probe query messages and ignore other Sequence Number TLVs if present. 4. Security Considerations The performance measurement is intended for deployment in well-managed private and service provider networks. The security considerations described in Section 8 of [RFC6374] are applicable to this specification, and particular attention should be paid to the last two paragraphs. Cryptographic measures may be enhanced by the correct configuration of access-control lists and firewalls. 5. IANA Considerations IANA is requested to allocate following UDP ports for performance measurements: o UDP Port TBA1: Delay Performance Measurement o UDP Port TBA2: Loss Performance Measurement IANA is also requested to allocate values for the following Return Path Segment List TLV Types for RFC 6374 to be carried in PM probe query messages: o Type TBA3: SR-MPLS Segment List of the Reverse SR Policy o Type TBA4: SRv6 Segment List of the Reverse SR Policy o Type TBA5: SR-MPLS Binding SID of the Reverse SR Policy o Type TBA6: SRv6 Binding SID of the Reverse SR Policy IANA is also requested to allocate a value for the following Sequence Number TLV Type for RFC 6374 to be carried in PM probe query and response messages: o Type TBA7: Sequence Number TLV Gandhi, et al. Expires December 11, 2018 [Page 14] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 6. References 6.1. Normative References [RFC768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, August 1980. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay Measurement for MPLS networks', RFC 6374, September 2011. [RFC7876] Bryant, S., Sivabalan, S., and Soni, S., "UDP Return Path for Packet Loss and Delay Measurement for MPLS Networks", RFC 7876, July 2016. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", RFC 8174, May 2017. 6.2. Informative References [IEEE1588] IEEE, "1588-2008 IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems", March 2008. [RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M. Zekauskas, "A One-way Active Measurement Protoco (OWAMP)", RFC 4656, September 2006. [RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", RFC 5357, October 2008. [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, "IPv6 Flow Label Specification", RFC 6437, November 2011. [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and L. Yong, "The Use of Entropy Labels in MPLS Forwarding", RFC 6790, November 2012. [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Kumar, N., Aldrin, S. and M. Chen, "Detecting Multiprotocol Label Switched (MPLS) Data-Plane Failures", RFC 8029, March 2017. [RFC8321] Fioccola, G. Ed., "Alternate-Marking Method for Passive and Hybrid Performance Monitoring", RFC 8321, January Gandhi, et al. Expires December 11, 2018 [Page 15] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 2018. [I-D.spring-segment-routing-policy] Filsfils, C., et al., "Segment Routing Policy Architecture", draft-ietf-spring-segment-routing-policy, work in progress. [I-D.6man-segment-routing-header] Filsfils, C., et al., "IPv6 Segment Routing Header (SRH)", draft-ietf-6man-segment-routing-header, work in progress. [I-D.spring-sr-mpls-pm] Filsfils, C., Gandhi, R. Ed., et al. "Performance Measurement in Segment Routing Networks with MPLS Data Plane", draft-gandhi-spring-sr-mpls-pm, work in progress. [I-D.pce-binding-label-sid] Filsfils, C., et al., "Carrying Binding Label Segment-ID in PCE-based Networks", draft-sivabalan-pce-binding-label-sid, work in progress. Gandhi, et al. Expires December 11, 2018 [Page 16] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 Acknowledgments The authors would like to thank Faisal Iqbal, Nagendra Kumar and Carlos Pignataro for the discussion on SRv6 Performance Measurement. Contributors Patrick Khordoc Cisco Systems, Inc. Email: pkhordoc@cisco.com Zafar Ali Cisco Systems, Inc. Email: zali@cisco.com Daniel Bernier Bell Canada Email: daniel.bernier@bell.ca Dirk Steinberg Steinberg Consulting Germany Email: dws@dirksteinberg.de Authors' Addresses Rakesh Gandhi (editor) Cisco Systems, Inc. Canada Email: rgandhi@cisco.com Clarence Filsfils Cisco Systems, Inc. Email: cfilsfil@cisco.com Sagar Soni Cisco Systems, Inc. Email: sagsoni@cisco.com Daniel Voyer Gandhi, et al. Expires December 11, 2018 [Page 17] Internet-Draft UDP Path for PM for Segment Routing June 9, 2018 Bell Canada Email: daniel.voyer@bell.ca Stefano Salsano Universita di Roma "Tor Vergata" Italy Email: stefano.salsano@uniroma2.it Pier Luigi Ventre CNIT Italy Email: pierluigi.ventre@cnit.it Gandhi, et al. Expires December 11, 2018 [Page 18]