Hi, Peter: Extend the meaning of "LSInifinity" for indicating the unreachability will again complex the deployment. Comply with the original rules for "LSInifinity" in related RFCs (that is, "bypass the SPF calculation for the prefixed that carried with this value") will generate less back compatible issues and also enable the future usage of "LSInfinity". As cited in your draft:(also in RFC5305)
"If a prefix is advertised with a metric larger then MAX_PATH_METRIC (0xFE000000, see paragraph 3.0), this prefix MUST NOT be considered during the normal SPF computation. This allows advertisement of a prefix for purposes other than building the normal IP routing table. " The "purposes" of such prefixes should be indicated explicitly by other means, as that proposed in the PUA draft. Best Regards Aijun Wang China Telecom -----Original Message----- From: [email protected] <[email protected]> On Behalf Of Peter Psenak Sent: Friday, August 5, 2022 1:55 PM To: Huzhibo <[email protected]> Cc: [email protected] Subject: Re: [Lsr] Question about draft-ppsenak-lsr-igp-ureach-prefix-announce Zhibo, On 03/08/2022 21:09, Huzhibo wrote: > Hi Peter: > Please see inline. > >> -----Original Message----- >> From: Peter Psenak [mailto:[email protected]] >> Sent: Wednesday, August 3, 2022 11:20 PM >> To: Huzhibo <[email protected]> >> Cc: [email protected] >> Subject: Re: Question about >> draft-ppsenak-lsr-igp-ureach-prefix-announce >> >> Hi Zhibo, >> >> On 29/07/2022 20:49, Huzhibo wrote: >>> Hi Peter: >>> >>> Supplement to yesterday's online questions, If a node that does not >>> support IP Flexalgo, which has a default route, should the node >>> process the IP Flexalgo prefix as a UPA? >> >> - I assume you are talking about the algo 0 default route. Because IP >> Flex-algo default route does not make much sense really. >> >> - If the node does not support IP flex-algo, than it would not use >> any IP algo prefix as BGP service endpoint or for any other purpose. >> > > Which IP Algo prefix as BGP service endpoint is not determined by the ingress node, Such as VXLAN and SRv6 VPN. > When the ingress node receives an BGP Service cayyied a IP algo prefix > as endpoint and it has a algo 0 default route, it should be process this BGP service. and this can not be affected by the IGP Flexalgo prefix. sorry, but above is completely wrong. When you want to use IP flex-algo forwarding, you must advertise the prefix as algo prefix, relying on the algo 0 default would not give you algo forwarding. Advertising IP algo prefix at the egress and relying in algo 0 default at the ingress is going to cause all sorts of problems. You CAN NOT mix/change algos along the path through the network - if you do, you may end up in a permanent loop. > Therefore, > the IGP does only not generate the RIB/Fib for LSinfinity Metric prefix, but can not trigger BGP Service Down. > In addition, LSinfinity Metric may be applied to other scenarios in > the future. We cannot guarantee that LSinfinity Metric will not conflict with other purposes when being processed as a UPA. no, it can not, because the LSinfinity has a very strict definition - it means unreachable, which is exactly what the UPA is about. Peter > >> - If such node receives the IP algo prefix and even if it treats it >> as UPA, given that such IP algo prefix was never reachable before on >> this node, the UPA would result in no action. >> >> thanks, >> Peter >>> >>> Thanks >>> >>> Zhibo >>> >> > > _______________________________________________ Lsr mailing list [email protected] https://www.ietf.org/mailman/listinfo/lsr _______________________________________________ Lsr mailing list [email protected] https://www.ietf.org/mailman/listinfo/lsr
