--- 1/draft-ietf-lsr-isis-rfc5306bis-07.txt 2019-09-19 15:13:18.334034147 -0700 +++ 2/draft-ietf-lsr-isis-rfc5306bis-08.txt 2019-09-19 15:13:18.390035566 -0700 @@ -1,19 +1,19 @@ IS-IS for IP Internets L. Ginsberg Internet-Draft P. Wells Obsoletes: 5306 (if approved) Cisco Systems, Inc. -Intended status: Standards Track September 18, 2019 -Expires: March 21, 2020 +Intended status: Standards Track September 19, 2019 +Expires: March 22, 2020 Restart Signaling for IS-IS - draft-ietf-lsr-isis-rfc5306bis-07 + draft-ietf-lsr-isis-rfc5306bis-08 Abstract This document describes a mechanism for a restarting router to signal to its neighbors that it is restarting, allowing them to reestablish their adjacencies without cycling through the down state, while still correctly initiating database synchronization. This document additionally describes a mechanism for a router to signal its neighbors that it is preparing to initiate a restart while @@ -46,21 +46,21 @@ 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 March 21, 2020. + This Internet-Draft will expire on March 22, 2020. Copyright Notice Copyright (c) 2019 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 @@ -207,25 +207,26 @@ system. It indicates the time after which the router will declare that it has failed to achieve database synchronization (by setting the overload bit in its own LSP). This is initialized to 65535 seconds, but is set to the minimum of the remaining times of received IIHs containing a restart TLV with the Restart Acknowledgement (RA) set and an indication that the neighbor has an adjacency in the "UP" state to the restarting router. (See Section 3.2.1a.) 3.2. Restart TLV - A new TLV is defined to be included in IIH PDUs. The presence of - this TLV indicates that the sender supports the functionality defined - in this document. The TLV includes flags that are used to convey - information during a (re)start. All IIHs transmitted by a router - that supports this capability MUST include this TLV. + A new TLV is defined to be included in IIH PDUs. The TLV includes + flags that are used to convey information during a (re)start. The + absence of this TLV indicates that the sender supports none of the + functionality defined in this document. Therefore, if a router + supports any of the functionality defined in this document it MUST + include this TLV in all transmitted IIHs. Type 211 Length: Number of octets in the Value field (1 to (3 + ID Length)) Value No. of octets +-----------------------+ | Flags | 1 @@ -272,26 +271,24 @@ is expecting an RA on a LAN circuit should assume that the acknowledgement is directed at the local system if the TLV is received with RA set and Restarting Neighbor System ID is not present. It is an implementation choice whether to continue to accept (on a LAN) a TLV with RA set and Restarting Neighbor System ID absent. Note that the omission of the Restarting Neighbor System ID only introduces ambiguity in the case where there are multiple systems on a LAN simultaneously performing restart. - The functionality associated with each of the defined flags (as - described in the following sections) is mutually exclusive with any - of the other flags. Therefore, it is expected that at most one flag - will be set in a TLV. When transmitting a TLV multiple flags MUST - NOT be set. Received TLVs which have multiple flags set MUST be - ignored. + The RR and SA flags may both be set in the TLV under the conditions + described in Section 3.3.2. All other flag combinations are invalid + and MUST NOT be transmitted. Received TLVs which have invalid flag + combinations set MUST be ignored. 3.2.1. Use of RR and RA Bits The RR bit is used by a (re)starting router to signal to its neighbors that a (re)start is in progress, that an existing adjacency SHOULD be maintained even under circumstances when the normal operation of the adjacency state machine would require the adjacency to be reinitialized, to request a set of CSNPs, and to request setting of the SRMflags. @@ -880,23 +877,20 @@ RX PR | Set Planned Restart | | state. | | Update hold time | Send PA | -------------+----------------------+------------------------- RX PR clr | Clear Planned | and RR clr | Restart State | | Restore holdtime to | | local value | -------------+----------------------+------------------------- - RX PA | Proceed with planned | - | restart | - -------------+----------------------+------------------------- RX RR | Maintain ADJ State | | Send RA | | Set SRM,send CSNP | | (Note 1) | | Update Hold Time, | | set Restart Mode | | (Note 2) | -------------+----------------------+------------------------- RX RR clr | Clr Restart mode | -------------+----------------------+------------------------- @@ -918,20 +912,23 @@ Event | Restarting | ADJ Seen | ADJ Seen | SPF Wait | | RA | CSNP | =================================================================== Restart | Send PR | | | planned | | | | ------------+--------------------+-----------+-----------+------------ Planned | Send PR clr | | | restart | | | | canceled | | | | ------------+--------------------+-----------+-----------+------------ + RX PA | Proceed with | | | + | planned restart | | | + ------------+--------------------+-----------+-----------+------------ Router | Send IIH/RR | | | restarts | ADJ Init | | | | Start T1,T2,T3 | | | ------------+--------------------+-----------+-----------+------------ RX RR | Send RA | | | ------------+--------------------+-----------+-----------+------------ RX RA | Adjust T3 | | Cancel T1 | | Goto ADJ Seen RA | | Adjust T3 | ----------- +--------------------+-----------+-----------+------------ RX CSNP set| Goto ADJ Seen CSNP | Cancel T1 | |