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In an OSPF link state database, each LSA is supposed to have a unique Link State ID (LSID). Sometimes this is not true, especially in multiple vendor devices environment.
When originating summary and/or AS-external LSAs, how to assign unique LSID for a network number who has multiple (different length of) masks is described in RFC 2328 appendix E. However, I did not see any discussion in RFC 2328 nor this archive how to handle/process summary and/or AS-external LSAs received from other routers with the same LSID but different length of masks.
According RFC 2328, a LSA is identified by LS type, LSID and advertising router. To determine which LSA of two LSA instances is newer, LS sequence number, checksum and age are compared. Network mask does not seem play any role while processing the received LSAs.
My question is, for example, if I received a LSA with LSID=A.B.C.D and 24 bits mask and installed in my database, and later I received the same LSA (i.e. same LS type, LSID and advertising router) but with 28 bits mask. If the second LSA has the larger sequence number, should I replace my database copy with the second LSA?
Thanks, Zhaoyang
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