--- 1/draft-ietf-bfd-unaffiliated-echo-03.txt 2022-02-08 19:13:15.032177299 -0800 +++ 2/draft-ietf-bfd-unaffiliated-echo-04.txt 2022-02-08 19:13:15.068178197 -0800 @@ -1,24 +1,24 @@ BFD Working Group W. Cheng Internet-Draft R. Wang Updates: 5880 (if approved) China Mobile Intended status: Standards Track X. Min, Ed. -Expires: 28 July 2022 ZTE Corp. +Expires: 12 August 2022 ZTE Corp. R. Rahman Individual R. Boddireddy Juniper Networks - 24 January 2022 + 8 February 2022 Unaffiliated BFD Echo - draft-ietf-bfd-unaffiliated-echo-03 + draft-ietf-bfd-unaffiliated-echo-04 Abstract Bidirectional Forwarding Detection (BFD) is a fault detection protocol that can quickly determine a communication failure between two forwarding engines. This document proposes a use of the BFD Echo where the local system supports BFD but the neighboring system does not support BFD. This document updates RFC 5880. @@ -31,21 +31,21 @@ 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 28 July 2022. + This Internet-Draft will expire on 12 August 2022. Copyright Notice Copyright (c) 2022 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 @@ -55,22 +55,22 @@ provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Conventions Used in This Document . . . . . . . . . . . . 3 2. Updates to RFC 5880 . . . . . . . . . . . . . . . . . . . . . 3 3. Unaffiliated BFD Echo Procedures . . . . . . . . . . . . . . 6 4. Unaffiliated BFD Echo Applicability . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 - 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 - 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 + 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction To minimize the impact of device/link faults on services and improve network availability, a network device must be able to quickly detect @@ -125,170 +125,153 @@ The Unaffiliated BFD Echo described in this document reuses the BFD Echo function as described in [RFC5880] and [RFC5881], but does not require BFD Asynchronous or Demand mode. When using the Unaffiliated BFD Echo, only the local system has the BFD protocol enabled; the remote system just loops back the received BFD Echo packets as regular data packets. This document updates [RFC5880] with respect to its descriptions on the BFD Echo function as follows. - * The 4th paragraph of Section 3.2 of [RFC5880] is updated as below: - - * OLD TEXT - - * An adjunct to both modes is the Echo function. + The 4th paragraph of Section 3.2 of [RFC5880] is updated as below: - * NEW TEXT + OLD TEXT + An adjunct to both modes is the Echo function. - * An adjunct to both modes is the Echo function, which can also be + NEW TEXT + An adjunct to both modes is the Echo function, which can also be running independently. - * OLD TEXT - - * Since the Echo function is handling the task of detection, the + OLD TEXT + Since the Echo function is handling the task of detection, the rate of periodic transmission of Control packets may be reduced (in the case of Asynchronous mode) or eliminated completely (in the case of Demand mode). - * NEW TEXT - - * Since the Echo function is handling the task of detection, the + NEW TEXT + Since the Echo function is handling the task of detection, the rate of periodic transmission of Control packets may be reduced (in the case of Asynchronous mode) or eliminated completely (in the case of Demand mode). The Echo function may also be used independently, with neither Asynchronous nor Demand mode. - * The 3rd and 9th paragraphs of Section 6.1 of [RFC5880] are updated - as below: - - * OLD TEXT + The 3rd and 9th paragraphs of Section 6.1 of [RFC5880] are updated as + below: - * Once the BFD session is Up, a system can choose to start the Echo + OLD TEXT + Once the BFD session is Up, a system can choose to start the Echo function if it desires and the other system signals that it will allow it. The rate of transmission of Control packets is typically kept low when the Echo function is active. - * NEW TEXT - - * When a system is running with Asynchronous or Demand mode, once + NEW TEXT + When a system is running with Asynchronous or Demand mode, once the BFD session is Up, it can choose to start the Echo function if it desires and the other system signals that it will allow it. The rate of transmission of Control packets is typically kept low for Asynchronous mode or eliminated completely for Demand mode when the Echo function is active. - * OLD TEXT - - * If the session goes Down, the transmission of Echo packets (if + OLD TEXT + If the session goes Down, the transmission of Echo packets (if any) ceases, and the transmission of Control packets goes back to the slow rate. - * NEW TEXT - - * In Asynchronous mode, if the session goes Down, the transmission + NEW TEXT + In Asynchronous mode, if the session goes Down, the transmission of Echo packets (if any) ceases, and the transmission of Control packets goes back to the slow rate. Demand mode MUST NOT be active if the session goes Down. - * The 2nd paragraph of Section 6.4 of [RFC5880] is updated as below: - - * OLD TEXT + The 2nd paragraph of Section 6.4 of [RFC5880] is updated as below: - * When a system is using the Echo function, it is advantageous to + OLD TEXT + When a system is using the Echo function, it is advantageous to choose a sedate reception rate for Control packets, since liveness detection is being handled by the Echo packets. This can be controlled by manipulating the Required Min RX Interval field (see section 6.8.3). - * NEW TEXT - - * When a system is using the Echo function with Asynchronous mode, + NEW TEXT + When a system is using the Echo function with Asynchronous mode, it is advantageous to choose a sedate reception rate for Control packets, since liveness detection is being handled by the Echo packets. This can be controlled by manipulating the Required Min RX Interval field (see section 6.8.3). Note that a system operating in Demand mode would direct the remote system to cease the periodic transmission of BFD Control packets, by setting the Demand (D) bit in its BFD Control packets. - * The 2nd paragraph of Section 6.8 of [RFC5880] is updated as below: - - * OLD TEXT + The 2nd paragraph of Section 6.8 of [RFC5880] is updated as below: - * When a system is said to have "the Echo function active" it means + OLD TEXT + When a system is said to have "the Echo function active" it means that the system is sending BFD Echo packets, implying that the session is Up and the other system has signaled its willingness to loop back Echo packets. - * NEW TEXT - - * When a system in Asynchronous or Demand mode is said to have "the + NEW TEXT + When a system in Asynchronous or Demand mode is said to have "the Echo function active" it means that the system is sending BFD Echo packets, implying that the session is Up and the other system has signaled its willingness to loop back Echo packets. - * The 7th paragraph of Section 6.8.3 of [RFC5880] is updated as - below: - - * OLD TEXT + The 7th paragraph of Section 6.8.3 of [RFC5880] is updated as below: - * When the Echo function is active, a system SHOULD set + OLD TEXT + When the Echo function is active, a system SHOULD set bfd.RequiredMinRxInterval to a value of not less than one second (1,000,000 microseconds). This is intended to keep received BFD Control traffic at a negligible level, since the actual detection function is being performed using BFD Echo packets. - * NEW TEXT - * When the Echo function is active with Asynchronous mode, a system + NEW TEXT + When the Echo function is active with Asynchronous mode, a system SHOULD set bfd.RequiredMinRxInterval to a value of not less than one second (1,000,000 microseconds). This is intended to keep received BFD Control traffic at a negligible level, since the actual detection function is being performed using BFD Echo packets. While a system operating in Demand mode would not receive BFD Control traffic. - * The 1st and 2nd paragraphs of Section 6.8.9 of [RFC5880] are - updated as below: - - * OLD TEXT + The 1st and 2nd paragraphs of Section 6.8.9 of [RFC5880] are updated + as below: - * BFD Echo packets MUST NOT be transmitted when bfd.SessionState is + OLD TEXT + BFD Echo packets MUST NOT be transmitted when bfd.SessionState is not Up. BFD Echo packets MUST NOT be transmitted unless the last BFD Control packet received from the remote system contains a nonzero value in Required Min Echo RX Interval. - * NEW TEXT - - * When a system is using the Echo function with either Asynchronous + NEW TEXT + When a system is using the Echo function with either Asynchronous or Demand mode, BFD Echo packets MUST NOT be transmitted when bfd.SessionState is not Up, and BFD Echo packets MUST NOT be transmitted unless the last BFD Control packet received from the remote system contains a nonzero value in Required Min Echo RX Interval. - * OLD TEXT - - * BFD Echo packets MAY be transmitted when bfd.SessionState is Up. + OLD TEXT + BFD Echo packets MAY be transmitted when bfd.SessionState is Up. The interval between transmitted BFD Echo packets MUST NOT be less than the value advertised by the remote system in Required Min Echo RX Interval... - * NEW TEXT - - * When a system is using the Echo function with either Asynchronous + NEW TEXT + When a system is using the Echo function with either Asynchronous or Demand mode, BFD Echo packets MAY be transmitted when bfd.SessionState is Up, and the interval between transmitted BFD Echo packets MUST NOT be less than the value advertised by the remote system in Required Min Echo RX Interval... 3. Unaffiliated BFD Echo Procedures + Device A Device B BFD Enabled BFD Echo packets loopback +--------+ BFD Echo session +--------+ | A |--------------------------------| B | | |Interface 1 Interface 1| | +--------+ +--------+ BFD is supported. BFD is not supported. Figure 1: Unaffiliated BFD Echo diagram @@ -388,25 +372,31 @@ The authors would like to acknowledge Ketan Talaulikar, Greg Mirsky and Santosh Pallagatti for their careful review and very helpful comments. The authors would like to acknowledge Jeff Haas for his insightful review and very helpful comments. 8. Contributors - Liu Aihua ZTE Email: liu.aihua@zte.com.cn + Liu Aihua + ZTE + Email: liu.aihua@zte.com.cn - Qian Xin ZTE Email: qian.xin2@zte.com.cn + Qian Xin + ZTE + Email: qian.xin2@zte.com.cn - Zhao Yanhua ZTE Email: zhao.yanhua3@zte.com.cn + Zhao Yanhua + ZTE + Email: zhao.yanhua3@zte.com.cn 9. References 9.1. 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, .