Jin, Regarding
>RFC3101 2.5 Calculating type-7 as external routes (3) states: >Else if the destination is a Type-7 default route (destination > ID = DefaultDestination) and one of the following is true, > then do nothing with this LSA and consider the next in the > list: > o The calculating router is a border router and the LSA has > its P-bit clear. Appendix E describes a technique > whereby an NSSA border router installs a Type-7 default > LSA without propagating it. > > o The calculating router is a border router and is > suppressing the import of summary routes as Type-3 > summary-LSAs. > [NSSA] >Suppose user perform following steps in scenario(there is one ABR and ASBR >in NSSA area): >1)ASBR generate type-7 default route LSA to redistribute default route >from static route source. >2)In ABR,Create type 7 default route LSA via command like >"default-route-originate" for this NSSA area. >After step 2),the ABR calculation also should not consider type-7 default >route LSA redistribted by ASBRs? >Am I missing something?please correct me. The answer is yes; but only if the P-bit is clear. From your text it would seem that you are using Cisco equipment. As far as I know Cisco IOS has no way of setting/clearing the P-bit in a route-map and its Type 7 LSAs almost always have the P-bit set. So most likely your ASBR's default route has the P-bit set and the ABR will install it. Setting/clearing the P-bit is a very useful feature as it allows an LSA's global propagation attribute to be set by its originating router. Without the ability to clear the P-bit, DoNotAdvertise ranges must be configured on every ABR when global propagation is not desired. Also since the default setting of the P-bit in RFC 3101 is clear, a RFC 3101 consistant implementation must have the ability to set the P-bit. Pat _______________________________________________ OSPF mailing list [email protected] https://www1.ietf.org/mailman/listinfo/ospf
