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Does it matter in what order an OSPF router receives LSA packets while reliable flooding is being performed in its area?

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The end result - that is the result after all changes have stopped and reliable flooding is completed should not depend on the order in which LSAs are received. (Intermediate results most likely do).

(1) LSAs from different source routers can arrive in any order, the only thing that matters is what LSAs are in the link state database at the time of calculation.

(2) LSAs from the same router of the same type are ordered based on sequence numbers, which are determined by the sender (given equal sequence numbers based on LSA age and a couple other fields that ensure completely deterministic outcome that leads to the same result on each router in the area - see sec 13.1 in RFC 2328). This ensures that the receiving routers will eventually accept the last LSA of the sending router even if "older" LSAs are received afterwards. As soon as the latest LSA is propagated, all routers should have it.


Inconsistent states during propagation do occur, because during changes link state databases are not yet identical. Each router can obviously compute routing tables based on its own link state database, which may temporary be different to other routers. You might want to google ordered fib updates. Also, routers may suppress routing table recalculations when lots of LSAs are being received - this is referred to as lsa throttling.

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