Hi, Tony: Aijun Wang China Telecom
> On Nov 25, 2021, at 03:59, Tony Li <tony...@tony.li> wrote: > > > > Hi Aijun, > >> If the scale is equal, then I would prefer to see flooding positive >> information rather than negative information. Operationally this is key: if >> there is a failure and positive information doesn’t propagate, then it’s a >> bug that will be found in due course and the operator can react outside of a >> failure scenario. >> [WAJ] What we want to do is the “Positive Summary”+” Specific Negative >> Information”. This can have both the summary scale advantage and also >> decrease the convergence time that based on the protocol hello timer. > > > I do understand that. Do you understand that I think that that’s a Really > Bad Idea? [WAJ] No. As we have discussed on the list, there is no other better solution to solve the problem. Actually, when ABR does the summary work, it may overstate the reachable addresses. When the host is within the summary range but is not used, it’s OK. But when the in-service host become unreachable and ABR knows this, it should give the other nodes the accurate information to assist them to switch to other services/backup points. > > > >> Increasing the size of the LSDB always affects performance. It slows >> flooding. Some nodes may not realize that SPF is not needed. When LSP >> fragments are rearranged, inferring that SPF is not necessary is >> non-trivial. Impacting router and network performance is a given. >> [WAJ] PUAM does not increase the overall size of the LSDB. It utilizes the >> existing LSA/TLV/Sub-TLV. > > > You’re advertising bits that would not be otherwise advertised. That > increases the size of the LSDB. Utilizing existing TLVs is irrelevant. [WAJ] No. OSPF/ISIS has been designed to be extensible to accommodate the newly necessary information. If we stick to your point, the fixed format LSA is sufficient. > > >> I have no objections to Robert’s BGP propagation ideas if that’s workable. >> >> This is simply not the IGP’s job and the IGP is not a dump truck. >> [WAJ] BGP is used within the internet, adding the false information within >> its protocol should be examined more carefully. As we have mentioned several >> times, the overall goals are not only for BGP usecaes, but also the >> prevailing Tunnel services. > > > Understood. BGP is also not a dump truck, but has far better scaling > properties, so is less likely to have catastrophic failures due to some > negative information. [WAJ] It is the IGP advertises the inaccurate information, why let BGP clear up? Won’t you estimate the IDR experts will resist? > > T > > > _______________________________________________ > Lsr mailing list > Lsr@ietf.org > https://www.ietf.org/mailman/listinfo/lsr
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