draft-ietf-pim-bfd-p2mp-use-case-05.txt   draft-ietf-pim-bfd-p2mp-use-case-06.txt 
PIM Working Group G. Mirsky PIM Working Group G. Mirsky
Internet-Draft ZTE Corp. Internet-Draft ZTE Corp.
Intended status: Standards Track J. Xiaoli Intended status: Standards Track J. Xiaoli
Expires: June 3, 2021 ZTE Corporation Expires: 5 February 2022 ZTE Corporation
November 30, 2020 4 August 2021
Bidirectional Forwarding Detection (BFD) for Multi-point Networks and The Use of Bidirectional Forwarding Detection (BFD) for Multipoint
Protocol Independent Multicast - Sparse Mode (PIM-SM) Use Case Networks in Protocol Independent Multicast - Sparse Mode (PIM-SM)
draft-ietf-pim-bfd-p2mp-use-case-05 draft-ietf-pim-bfd-p2mp-use-case-06
Abstract Abstract
This document discusses the use of Bidirectional Forwarding Detection This document specifies the use of Bidirectional Forwarding Detection
(BFD) for multi-point networks to provide nodes that participate in (BFD) for multipoint networks to provide nodes that participate in
Protocol Independent Multicast - Sparse Mode (PIM-SM) with the sub- Protocol Independent Multicast - Sparse Mode (PIM-SM) with sub-second
second convergence. Optional extension to PIM-SM Hello, as specified convergence. An extension to the PIM Hello message used to bootstrap
in RFC 7761, to bootstrap point-to-multipoint BFD session. also point-to-multipoint BFD sessions is also defined in this document.
defined in this document.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 3, 2021. This Internet-Draft will expire on 5 February 2022.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents (https://trustee.ietf.org/
(https://trustee.ietf.org/license-info) in effect on the date of license-info) in effect on the date of publication of this document.
publication of this document. Please review these documents Please review these documents carefully, as they describe your rights
carefully, as they describe your rights and restrictions with respect and restrictions with respect to this document. Code Components
to this document. Code Components extracted from this document must extracted from this document must include Simplified BSD License text
include Simplified BSD License text as described in Section 4.e of as described in Section 4.e of the Trust Legal Provisions and are
the Trust Legal Provisions and are provided without warranty as provided without warranty as described in the Simplified BSD License.
described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions used in this document . . . . . . . . . . . . 3 1.1. Conventions used in this document . . . . . . . . . . . . 3
1.1.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . 3 1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 3
1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3 1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 4 2. BFD Discriminator PIM Hello Option . . . . . . . . . . . . . 3
3. Applicability of p2mp BFD . . . . . . . . . . . . . . . . . . 4 2.1. Using P2MP BFD in PIM DR/BDR Monitoring . . . . . . . . . 4
3.1. Using P2MP BFD in PIM DR/BDR Monitoring . . . . . . . . . 4 2.2. P2MP BFD in PIM DR Load Balancing . . . . . . . . . . . . 5
3.2. P2MP BFD in PIM DR Load Balancing . . . . . . . . . . . . 5 2.3. Multipoint BFD Encapsulation . . . . . . . . . . . . . . 5
3.3. Multipoint BFD Encapsulation . . . . . . . . . . . . . . 6 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 7 6.2. Informative References . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
Faster convergence in the control plane, in general, is beneficial Faster convergence in the control plane, in general, is beneficial
and allows minimizing periods of traffic blackholing, transient and allows minimizing periods of traffic blackholing, transient
routing loops, and other scenarios that may negatively affect service routing loops, and other scenarios that may negatively affect service
data flow. That equally applies to unicast and multicast routing data flow. That equally applies to unicast and multicast routing
protocols. protocols.
[RFC7761] is the current specification of the Protocol Independent [RFC7761] is the current specification of the Protocol Independent
Multicast - Sparse Mode (PIM-SM) for IPv4 and IPv6 networks. Multicast - Sparse Mode (PIM-SM) for IPv4 and IPv6 networks. A
Confirming implementation of PIM-SM elects a Designated Router (DR) conforming implementation of PIM-SM elects a Designated Router (DR)
on each PIM-SM interface. When a group of PIM-SM nodes is connected on each PIM-SM interface. When a group of PIM-SM nodes is connected
to shared-media segment, e.g., Ethernet, the one elected as DR is to to a shared-media segment, e.g., Ethernet, the node elected as DR is
act on behalf of directly connected hosts in the context of the PIM- to act on behalf of directly connected hosts in the context of the
SM protocol. Failure of the DR impacts the quality of the multicast PIM-SM protocol. Failure of the DR impacts the quality of the
services it provides to directly connected hosts because the default multicast services it provides to directly connected hosts because
failure detection interval for PIM-SM routers is 105 seconds. the default failure detection interval for PIM-SM routers is 105
Introduction of Backup DR (BDR), proposed in seconds. Introduction of Backup DR (BDR)
[I-D.ietf-pim-dr-improvement], improves convergence time in the PIM- ([I-D.ietf-pim-dr-improvement]) improves convergence time in PIM-SM
SM over shared-media segment but still depends on long failure over shared-media segment but still depends on a long failure
detection interval. detection interval.
Bidirectional Forwarding Detection (BFD) [RFC5880] had been Bidirectional Forwarding Detection (BFD) [RFC5880] had been
originally defined to detect failure of point-to-point (p2p) paths - originally defined to detect failure of point-to-point (p2p) paths -
single-hop [RFC5881], multihop [RFC5883]. In some PIM-SM single-hop [RFC5881], multihop [RFC5883]. In some PIM-SM
deployments, a p2p BFD can be used to detect a failure and enable deployments, a p2p BFD can be used to detect a failure and enable
faster conversion. [RFC8562] extends the BFD base specification faster conversion. [RFC8562] extends the BFD base specification
[RFC5880] for multipoint and multicast networks, which precisely [RFC5880] for multipoint and multicast networks precisely
characterizes deployment scenarios for PIM-SM over a LAN segment. characterizes deployment scenarios for PIM-SM over a LAN segment.
Among specific characteristics of p2mp BFD that are particularly Among specific characteristics of p2mp BFD that particularly benefit
benefit PIM-SM over a LAN segment is a faster transition to the Up PIM-SM over a LAN segment is a faster transition to the Up state of
state of the p2mp BFD session due to avoidance of the three-way the p2mp BFD session due to avoidance of the three-way handshake
handshake required in p2p BFD [RFC5880]. Also, because the router required in p2p BFD [RFC5880]. Also, because the router that
that transmits BFD Control messages uses the BFD Demand mode transmits BFD Control messages uses the BFD Demand mode [RFC5880], it
[RFC5880] it maintains less BFD state comparing to the Asynchronous maintains less BFD state comparing to the Asynchronous mode. Point-
mode. This document demonstrates how point-to-multipoint (p2mp) BFD to-multipoint (p2mp) BFD can enable faster detection of PIM-SM router
can enable faster detection of PIM-SM router failure and thus failure and thus minimize multicast service disruption. The
minimize multicast service disruption. The document also defines the monitored PIM-SM router acts as the head and other routers as tails
extension to PIM-SM [RFC7761] and [I-D.ietf-pim-dr-improvement] to of a p2mp BFD session. This document defines the monitoring of PIM-
bootstrap a PIM-SM router to join in p2mp BFD session over shared- SM DR and BDR using p2mp BFD. Other cases of using p2mp BFD in PIM-
media link. SM are outside the scope of this specification. The document also
defines the extension to PIM-SM [RFC7761] to bootstrap a PIM-SM
router to join in p2mp BFD session over shared-media link.
1.1. Conventions used in this document 1.1. Conventions used in this document
1.1.1. Acronyms 1.1.1. Terminology
BFD: Bidirectional Forwarding Detection
BDR: Backup Designated Router
DR: Designated Router
DRLB: Designated Router Load Balancing
DRLB-Cap: DRLB Capability Hello Option
DRLB-List: DRLB List Hello Option
GDR: Group Designated Router
p2mp: Point-to-Multipoint
p2p: Point-to-Point
PIM-SM: Protocol Independent Multicast - Sparse Mode This document uses terminology defined in [RFC5880], [RFC8562], and
[RFC7761]. familiarity with these specifications and the terminology
used is expected.
1.1.2. Requirements Language 1.1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
2. Problem Statement 2. BFD Discriminator PIM Hello Option
[RFC7761] does not provide a method for fast, e.g., sub-second,
failure detection of a neighbor PIM-SM router. BFD already has many
implementations based on HW that are capable of supporting multiple
sub-second sessions concurrently.
3. Applicability of p2mp BFD
[RFC8562] may provide an efficient and scalable solution for the Figure 1 displays the new optional BFD Discriminator PIM Hello option
fast-converging environment that demonstrates the head-tails to bootstrap a tail of the p2mp BFD session.
relationship. Each such group presents itself as p2mp BFD session
with its head being the root and other routers being tails of the
p2mp BFD session. Figure 1 displays the new optional BFD
Discriminator PIM Hello Option to bootstrap tail of the p2mp BFD
session.
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OptionType | OptionLength | | OptionType | OptionLength |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| My Discriminator | | My Discriminator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: BFD Discriminator PIM Hello Option Figure 1: BFD Discriminator PIM Hello Option
where new fields are interpreted as: where new fields are interpreted as:
OptionType is a value (TBA1) assigned by IANA Section 4 that OptionType: TBA.
identifies the TLV as BFD Discriminator TLV;
OptionLength value is always 4 OptionLength: MUST be set to 4.
My Discriminator - My Discriminator value allocated by the root of My Discriminator: My Discriminator ([RFC5880]) value allocated by
the p2mp BFD session. the head.
3.1. Using P2MP BFD in PIM DR/BDR Monitoring If the value of the OptionLength field is not equal to 4, the BFD
Discriminator PIM Hello option is considered malformed, and the
receiver MUST stop processing PIM Hello options. If the value of the
My Discriminator field equals zero, then the BFD Discriminator PIM
Hello option MUST be considered invalid, and the receiver MUST ignore
it. The receiver SHOULD log the notification regarding the malformed
or invalid BFD Discriminator Hello option under the control of a
throttling logging mechanism.
If PIM-SM routers that support this specification are configured to 2.1. Using P2MP BFD in PIM DR/BDR Monitoring
use p2mp BFD for faster convergence, then the router to be monitored,
referred to as 'head', MUST create a BFD session of type
MultipointHead, as defined in [RFC8562]. Note that any PIM-SM router
that supports this specification, regardless of its role in PIM-SM,
MAY become a head of a p2mp BFD session. If the head doesn't support
[I-D.ietf-pim-dr-improvement], but, for example, uses procedures
defined in [I-D.mankamana-pim-bdr], then it MUST include BFD TLV in
its PIM-Hello message. If the head uses extensions defined in
[I-D.ietf-pim-dr-improvement], then DR MUST include BFD TLV in its The head MUST create a BFD session of type MultipointHead [RFC8562].
Hello message. The DR Address TLV also MUST be included in the Hello Note that any PIM-SM router, regardless of its role, MAY become a
message. For a BDR, it is RECOMMENDED to include BFD TLV in its head of a p2mp BFD session. The head MUST include the BFD
Hello message. If BDR includes BFD TLV, then the BDR Address TLV Discriminator option in its Hello messages.
also MUST be present in the Hello message. As mentioned earlier, any
non-DR and non-BDR MAY include BFD TLV in its Hello message. Then
the head MUST begin periodic transmission of BFD Control packets.
The Source IP address of the BFD Control packet MUST be the same as
the source IP address of the PIM-Hello with BFD TLV messages being
transmitted by the head. My Discriminator's field value in the BFD
Control packet and My Discriminator field of the BFD TLV in PIM-
Hello, transmitted by the head, MUST be the same. When a PIM-SM
router is configured to monitor the head by using p2mp BFD, referred
to through this document as 'tail', receives PIM-Hello packet with
BFD TLV, the tail MAY create a p2mp BFD session of type
MultipointTail, as defined in [RFC8562].
Because p2mp BFD doesn't use the three-way handshake and the head If a PIM-SM router is configured to monitor the head by using p2mp
transmits BFD Control packets with the value of Your Discriminator BFD, referred to through this document as 'tail', receives PIM-Hello
field set to zero, [RFC8562] modified how a BFD system demultiplexes packet with BFD Discriminator PIM Hello option, the tail MAY create a
received BFD Control packet. The tail demultiplexes p2mp BFD test p2mp BFD session of type MultipointTail, as defined in [RFC8562].
session based on head's source IP address, the My Discriminator value
it learned from BFD Discriminator TLV and the identity of the
multipoint path that the BFD Control packet was received from. The
Detection Time for p2mp BFD sessions is defined differently from the
definition provided in [RFC5880]. The Detection Time for each
MultipointTail session is calculated as the product of the last
received values of Desired Min TX Interval and Detect Mult. A tail
declares the BFD session down after the Detection Timer expires. If
the tail has detected MultipointHead failure, it MUST remove the
neighbor. If the failed head node was PIM-SM DR or BDR, the tail MAY
start DR Election process as specified in Section 4.3.2 [RFC7761] or
Section 4.1 [I-D.ietf-pim-dr-improvement] respectively.
If the head ceased to include BFD TLV in its PIM-Hello message, tails The node that includes the BFD Discriminator PIM Hello option
MUST close the corresponding MultipointTail BFD session. Thus the transmits BFD Control packets periodically. For the tail to
tail stops using BFD to monitor the head and reverts to the correctly demultiplex BFD [RFC8562], the source address, and My
procedures defined in [RFC7761] and [I-D.ietf-pim-dr-improvement]. Discriminator values of the BFD packets MUST be the same as those
used in the PIM Hello message. If that is not the case, the tail BFD
node would not be able to monitor the state of the PIM-SM node, that
is the head of the p2mp BFD session, though the regular PIM-SM
mechanisms remain fully operational.
3.2. P2MP BFD in PIM DR Load Balancing If the tail detects a MultipointHead failure [RFC8562], it MUST
delete the corresponding neighbor state. If the failed head was the
DR (or BDR), the DR (or BDR) election mechanism in [RFC7761] or
[I-D.ietf-pim-dr-improvement] is followed.
[RFC8775] defined the modification, Designated Router Load Balancing If the head ceases to include the BFD Discriminator PIM Hello option
(DRLB), to the PIM-SM protocol that allows for distribution of PIM-SM in its PIM-Hello message, tails MUST close the corresponding
DR responsibilities on a multi-access network segment. [RFC8775] MultipointTail BFD session. Thus the tail stops using BFD to monitor
introduced the new PIM Hello options - Load Balancing Capability the head and reverts to the procedures defined in [RFC7761] and
(DRLB-Cap) and DR Load Balancing List (DRLB-List). PIM router that [I-D.ietf-pim-dr-improvement].
includes DRLB-Cap Hello Option MAY include BFD Discriminator PIM
Hello Option (Figure 1). That router MUST create a BFD session and
set itself as MultipointHead [RFC8562]. The router MUST set
bfd.SessionState in the MultipointHead session to Down. If a PIM
router that includes BFD Discriminator Option in its Hello finds its
address in DRLB-List PIM Hello Option as Group Designated Router
(GDR) Candidate for the first time, the router MUST set
bfd.SessionState to Up and start periodically transmit BFD Control
messages. If the PIM router that was GDR Candidate doesn't find its
address in the most recent DRLB-List Option, the router MUST set
bfd.SessionState to Down and cease transmitting BFD Control messages.
For each GDR Candidate that includes BFD Discriminator Option in its
PIM Hello, PIM DR creates a MultipointTail session [RFC8562]. PIM DR
demultiplexes BFD sessions based on the value in My Discriminator
field and the source IP address. If PIM DR detects a failure of one
of the sessions, it MUST remove that router from the GDR Candidate
list and immediately transmit a new DRLB-List Option.
3.3. Multipoint BFD Encapsulation 2.2. P2MP BFD in PIM DR Load Balancing
The MultipointHead of p2mp BFD session when transmitting BFD Control [RFC8775] specifies the PIM Designated Router Load Balancing (DRLB)
packet: functionality. Any PIM router that advertises the DRLB-Cap Hello
Option can become the head of a p2mp BFD session, as specified in
Section 2.1. The head router administratively sets the
bfd.SessionState to Up in the MultipointHead session [RFC8562] only
if it is a Group Designated Router (GDR) Candidate, as specified in
Sections 5.5 and 5.6 of [RFC8775]. If the router is no longer the
GDR, then it MUST shut down following the procedures described in
Section 5.9 [RFC8562]. For each GDR Candidate that includes BFD
Discriminator option in its PIM Hello, the PIM DR creates a
MultipointTail session [RFC8562]. PIM DR demultiplexes BFD sessions
based on the value of the My Discriminator field and the source IP
address. If PIM DR detects a failure of one of the sessions, it MUST
remove that router from the GDR Candidate list and immediately
transmit a new DRLB-List option.
MUST set TTL value to 1; 2.3. Multipoint BFD Encapsulation
SHOULD use group address ALL-PIM-ROUTERS ('224.0.0.13' for IPv4 The MultipointHead of a p2mp BFD session when transmitting BFD
and 'ff02::d' for IPv6) as destination IP address Control packet:
MAY use network broadcast address for IPv4 or link-local all nodes MUST set TTL or Hop Limit value to 255 (Section 5 [RFC5881]);
multicast group for IPv6 as the destination IP address;
MUST set destination UDP port value to 3784 when transmitting BFD MUST use the group address ALL-PIM-ROUTERS ('224.0.0.13' for IPv4
Control packets, as defined in [RFC8562]. and 'ff02::d' for IPv6) as destination IP address
4. IANA Considerations 3. IANA Considerations
IANA is requested to allocate a new OptionType value from PIM Hello IANA is requested to allocate a new OptionType value from PIM-Hello
Options registry according to: Options registry according to:
+-------------+----------------+-------------------+---------------+ +=============+================+===================+===============+
| Value Name | Length Number | Name Protocol | Reference | | Value Name | Length Number | Name Protocol | Reference |
+-------------+----------------+-------------------+---------------+ +=============+================+===================+===============+
| TBA | 4 | BFD Discriminator | This document | | TBA | 4 | BFD Discriminator | This document |
| | | Option | |
+-------------+----------------+-------------------+---------------+ +-------------+----------------+-------------------+---------------+
Table 1: BFD Discriminator option type Table 1: BFD Discriminator option type
5. Security Considerations 4. Security Considerations
Security considerations discussed in [RFC7761], [RFC5880], and
[RFC8562], and [I-D.ietf-pim-dr-improvement] apply to this document.
PIM-SM link-local messages can be authenticated using various The security considerations discussed in [RFC7761], [RFC5880],
mechanisms, as described in Section 6.3 [RFC7761]. Authentication of [RFC8562], [RFC8775], and [I-D.ietf-pim-dr-improvement] apply to this
BFD Control messages defined in Section 6.7 [RFC5880]. Each protocol document.
MAY use authentication of its messages independently of the mode used
by the other protocol.
An implementation that supports this specification SHOULD use a An implementation that supports this specification SHOULD use a
mechanism to control the maximum number of BFD sessions that can be mechanism to control the maximum number of BFD sessions that can be
active at the same time. active at the same time.
6. Acknowledgments 5. Acknowledgments
Authors cannot say enough to express their appreciation of comments The authors cannot say enough to express their appreciation of the
and suggestions we received from Stig Venaas. comments and suggestions we received from Stig Venaas. The authors
greatly appreciate the comments and suggestions by Alvaro Retana that
improved the clarity of the document.
7. References 6. References
7.1. Normative References 6.1. Normative References
[I-D.ietf-pim-dr-improvement] [I-D.ietf-pim-dr-improvement]
Zhang, Z., hu, f., Xu, B., and M. Mishra, "Protocol Zhang, Z., Hu, F., Xu, B., and M. Mishra, "Protocol
Independent Multicast - Sparse Mode (PIM-SM) Designated Independent Multicast - Sparse Mode (PIM-SM) Designated
Router (DR) Improvement", draft-ietf-pim-dr-improvement-10 Router (DR) Improvement", Work in Progress, Internet-
(work in progress), September 2020. Draft, draft-ietf-pim-dr-improvement-11, 17 February 2021,
<https://www.ietf.org/archive/id/draft-ietf-pim-dr-
improvement-11.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<https://www.rfc-editor.org/info/rfc5880>. <https://www.rfc-editor.org/info/rfc5880>.
[RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
DOI 10.17487/RFC5881, June 2010,
<https://www.rfc-editor.org/info/rfc5881>.
[RFC5883] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for Multihop Paths", RFC 5883, DOI 10.17487/RFC5883,
June 2010, <https://www.rfc-editor.org/info/rfc5883>.
[RFC7761] Fenner, B., Handley, M., Holbrook, H., Kouvelas, I., [RFC7761] Fenner, B., Handley, M., Holbrook, H., Kouvelas, I.,
Parekh, R., Zhang, Z., and L. Zheng, "Protocol Independent Parekh, R., Zhang, Z., and L. Zheng, "Protocol Independent
Multicast - Sparse Mode (PIM-SM): Protocol Specification Multicast - Sparse Mode (PIM-SM): Protocol Specification
(Revised)", STD 83, RFC 7761, DOI 10.17487/RFC7761, March (Revised)", STD 83, RFC 7761, DOI 10.17487/RFC7761, March
2016, <https://www.rfc-editor.org/info/rfc7761>. 2016, <https://www.rfc-editor.org/info/rfc7761>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8562] Katz, D., Ward, D., Pallagatti, S., Ed., and G. Mirsky, [RFC8562] Katz, D., Ward, D., Pallagatti, S., Ed., and G. Mirsky,
Ed., "Bidirectional Forwarding Detection (BFD) for Ed., "Bidirectional Forwarding Detection (BFD) for
Multipoint Networks", RFC 8562, DOI 10.17487/RFC8562, Multipoint Networks", RFC 8562, DOI 10.17487/RFC8562,
April 2019, <https://www.rfc-editor.org/info/rfc8562>. April 2019, <https://www.rfc-editor.org/info/rfc8562>.
[RFC8775] Cai, Y., Ou, H., Vallepalli, S., Mishra, M., Venaas, S., [RFC8775] Cai, Y., Ou, H., Vallepalli, S., Mishra, M., Venaas, S.,
and A. Green, "PIM Designated Router Load Balancing", and A. Green, "PIM Designated Router Load Balancing",
RFC 8775, DOI 10.17487/RFC8775, April 2020, RFC 8775, DOI 10.17487/RFC8775, April 2020,
<https://www.rfc-editor.org/info/rfc8775>. <https://www.rfc-editor.org/info/rfc8775>.
7.2. Informative References 6.2. Informative References
[I-D.mankamana-pim-bdr] [RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
Mishra, M., Goh, J., and G. Mishra, "PIM Backup Designated (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
Router Procedure", draft-mankamana-pim-bdr-04 (work in DOI 10.17487/RFC5881, June 2010,
progress), April 2020. <https://www.rfc-editor.org/info/rfc5881>.
[RFC5883] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for Multihop Paths", RFC 5883, DOI 10.17487/RFC5883,
June 2010, <https://www.rfc-editor.org/info/rfc5883>.
Authors' Addresses Authors' Addresses
Greg Mirsky Greg Mirsky
ZTE Corp. ZTE Corp.
Email: gregimirsky@gmail.com Email: gregimirsky@gmail.com
Ji Xiaoli Ji Xiaoli
ZTE Corporation ZTE Corporation
No.50 Software Avenue, Yuhuatai District No.50 Software Avenue, Yuhuatai District
Nanjing Nanjing,
China China
Email: ji.xiaoli@zte.com.cn Email: ji.xiaoli@zte.com.cn
 End of changes. 50 change blocks. 
213 lines changed or deleted 155 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/