On September 23, 2019 at 3:29:55 PM, Padma Pillay-Esnault ( [email protected]) wrote:
Padma: Hi! (1) §3 (last paragraph) introduces different behavior for permanently vs > temporarily acting as a host. From the point of view of the H-bit, what is > the difference? It seems to me that in both cases the H-bit would be set: > the router would be acting as a host NOW. How long it keeps the H-bit set > seems to be the distinction between permanent and temporary...but the > behavior should not change because of that. IOW, the specification of what > happens when the H-bit is set should be singular -- you may be able to > soften some of the MUSTs (to SHOULD) if the exceptions are justified other > than using time. > > PPE > I agree that the the specification should be singular. I propose this change OLD: Therefore, non-local IPv4 prefixes, e.g., those exported from other routing protocols, MUST NOT be advertised in AS- external-LSAs for routers acting permanently as a host. NEW: Therefore, non-local IPv4 prefixes, e.g., those exported from other routing protocols, SHOULD NOT be advertised in AS- external-LSAs for routers acting permanently as a host. The last sentence below the MUST is correct to correctly repel. Current : In addition to the procedure described above, temporary host routers advertising type 2-metric External LSAs MUST set the metrics to LSInfinity to repel traffic.(see Section 6 of this document). The proposed changes didn’t eliminate the duality between permanent and temporary. We need to eliminate that! Said another way: how would the router know the difference in behavior between a permanent setting and a temporary one? What is the time limit between temporary/permanent? … NEW (suggestion)> When the H-bit is set the host router cannot act as an AS Boundary Router (ASBR). Indeed, ASBR are transit routers to prefixes that are typically imported through redistribution of prefixes from other routing protocols. Therefore, non-local IPv4 prefixes, e.g., those imported from other routing protocols, SHOULD NOT be advertised in AS-external-LSAs if the H-bit is set. Some use cases, such as an overloaded router or a router being gracefully isolated, may benefit from continued advertisement of non-local prefixes. In these cases, the type 2-metric in AS-external-LSAs MUST be set to LSInfinity to repel traffic.(see Section 6 of this document). I’ll start the IETF Last Call when -10 is submitted. Thanks! Alvaro.
_______________________________________________ Lsr mailing list [email protected] https://www.ietf.org/mailman/listinfo/lsr
