> On Mar 7, 2023, at 2:19 AM, Mengxiao.Chen <[email protected]> wrote: > > Hi Les, > > Thank you for your comments. > OSPF does include the LSDB sync requirement. But OSPF state machine does not > guarantee the two routers attain FULL state at the same time. > > R1(restart)------R2------R3 > > R1 LSDB: R1's new router-LSA, seq 80000001 > R2 LSDB: R1's old router-LSA, seq 80000500 > > When R1 restarts from an unplanned outage, R1 will reinitialize its LSA > sequence number. But R2 has the previous copies of R1's LSA, which has larger > sequence number. > R2 thinks its local LSAs are "newer". So, R2 will attain FULL state, without > requesting R1 to update. > This may cause temporary blackholes to occur until R1 regenerates and floods > its own LSAs with higher sequence numbers.
A link will not be used unless both sides advertise it. Refer to section 16.1, step (2), check (b). Acee > > Thanks, > Mengxiao > > -----Original Message----- > From: Lsr <[email protected]> On Behalf Of Les Ginsberg (ginsberg) > Sent: Tuesday, March 7, 2023 1:29 AM > To: Acee Lindem <[email protected]>; Liyan Gong <[email protected]> > Cc: lsr <[email protected]> > Subject: Re: [Lsr] New Version Notification for > draft-cheng-ospf-adjacency-suppress-00.txt > > +1 to what Acee has said. > > As historical context, the SA bit was defined in IS-IS precisely because > IS-IS adjacency state machine does NOT include LSPDB sync as a requirement > before the adjacency is usable (unlike OSPF). > OSPF does not need SA bit. > > Les > >> -----Original Message----- >> From: Lsr <[email protected]> On Behalf Of Acee Lindem >> Sent: Monday, March 6, 2023 8:01 AM >> To: Liyan Gong <[email protected]> >> Cc: lsr <[email protected]> >> Subject: Re: [Lsr] New Version Notification for draft-cheng-ospf-adjacency- >> suppress-00.txt >> >> Hi Liyan, >> >> I should replied to this Email rather than your request for an IETF 116 slot. >> Please reply to this one. >> >> I’m sorry but I don’t get this draft from a quick read. An OSPF router would >> not advertise an adjacency until the router is in FULL state. An OSPF router >> will not attain FULL state until database synchronization is complete. >> The following statement from you use case is incorrect: >> >> So, without requesting the starting router to update its LSAs, the >> neighbors of the starting router may transition to "Full" state and >> route the traffic through the starting router. >> >> Why do you think you need this extension? >> >> >> Thanks, >> Acee >> >> >>> On Mar 6, 2023, at 9:10 AM, Liyan Gong <[email protected]> >> wrote: >>> >>> Dear All, >>> We have posted a new draft https://datatracker.ietf.org/doc/draft-cheng- >> ospf-adjacency-suppress/. >>> This draft describes the extension of OSPF LLS to signal adjacency >> suppression which is functionally similar to the SA bit of Restart TLV in >> IS-IS. >>> The purpose is to avoid the temporary blackhole when a router restarts >> from unplanned outages. >>> We are looing forward to your comments.Thanks a lot. >>> >>> Best Regards, >>> Liyan >>> >>> ----邮件原文---- >>> 发件人：internet-drafts <[email protected]> >>> 收件人：Changwang Lin <[email protected]>,Liyan Gong >> <[email protected]>,Mengxiao Chen >> <[email protected]>,Weiqiang Cheng >> <[email protected]> >>> 抄 送: (无) >>> 发送时间：2023-03-06 17:43:39 >>> 主题：New Version Notification for draft-cheng-ospf-adjacency-suppress- >> 00.txt >>> >>> >>> A new version of I-D, draft-cheng-ospf-adjacency-suppress-00.txt >>> has been successfully submitted by Mengxiao Chen and posted to the >>> IETF repository. >>> >>> Name: draft-cheng-ospf-adjacency-suppress >>> Revision: 00 >>> Title: OSPF Adjacency Suppression >>> Document date: 2023-03-06 >>> Group: Individual Submission >>> Pages: 8 >>> URL: https://www.ietf.org/archive/id/draft-cheng-ospf-adjacency- >> suppress-00.txt >>> Status: https://datatracker.ietf.org/doc/draft-cheng-ospf-adjacency- >> suppress/ >>> Htmlized: https://datatracker.ietf.org/doc/html/draft-cheng-ospf- >> adjacency-suppress >>> >>> >>> Abstract: >>> This document describes a mechanism for a router to signal its >>> neighbors to suppress advertising the adjacency to it until link- >>> state database synchronization is complete. This minimizes transient >>> routing disruption when a router restarts from unplanned outages. >>> >>> >>> >>> >>> The IETF Secretariat >>> >>> >>> >>> Subject：New Version Notification for draft-cheng-ospf-adjacency- >> suppress-00.txt >>> >>> >>> A new version of I-D, draft-cheng-ospf-adjacency-suppress-00.txt >>> has been successfully submitted by Mengxiao Chen and posted to the >>> IETF repository. >>> >>> Name: draft-cheng-ospf-adjacency-suppress >>> Revision: 00 >>> Title: OSPF Adjacency Suppression >>> Document date: 2023-03-06 >>> Group: Individual Submission >>> Pages: 8 >>> URL: https://www.ietf.org/archive/id/draft-cheng-ospf-adjacency- >> suppress-00.txt >>> Status: https://datatracker.ietf.org/doc/draft-cheng-ospf-adjacency- >> suppress/ >>> Htmlized: https://datatracker.ietf.org/doc/html/draft-cheng-ospf- >> adjacency-suppress >>> >>> >>> Abstract: >>> This document describes a mechanism for a router to signal its >>> neighbors to suppress advertising the adjacency to it until link- >>> state database synchronization is complete. This minimizes transient >>> routing disruption when a router restarts from unplanned outages. >>> >>> >>> >>> >>> The IETF Secretariat >>> >>> >>> >>> _______________________________________________ >>> Lsr mailing list >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/lsr >> >> _______________________________________________ >> Lsr mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/lsr > _______________________________________________ > Lsr mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/lsr > ------------------------------------------------------------------------------------------------------------------------------------- > 本邮件及其附件含有新华三集团的保密信息，仅限于发送给上面地址中列出 > 的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制、 > 或散发）本邮件中的信息。如果您错收了本邮件，请您立即电话或邮件通知发件人并删除本 > 邮件！ > This e-mail and its attachments contain confidential information from New > H3C, which is > intended only for the person or entity whose address is listed above. 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