Hi,
Normal OSPF deign best practice recommends that you should consider the following,
Below are some highlted recommended and there a lot based on your design...:)
•Summarizing intra-area routes is recommended in most cases.
•If an area has multiple ABRs, then the summarization for the same range of routes should be configured on all the ABRs in the area.
•Since summarization for the same range of addresses on multiple ABRs in some topologies (typically hub and spoke topologies) can, in some situations, cause routing black holes it is generally best to have at least one link between two ABRs summarizing the same address space within the non-backbone area.
•Make sure that the ‘null 0’ route (discard route) is installed for the summarized address ranges to avoid routing loops in some scenarios.
•It is preferable to set manually the cost of the summary route, or use a loopback interface in the summarized IP address range to prevent the summary cost from changing due to network changes within the area.
•Having more than one ABR for areas is recommended for redundancy.
•Summarize externally learned routes at the redistribution point (ASBR) to reduce the external LSAs where possible, since external LSAs are flooded throughout the OSPF domain.
•Avoid configuring redistribute connected under the OSPF routing process. Instead, use the network statement under OSPF process and mark those interfaces as passive.
•If redistribution is required, limit it to as fewer routers as possible.
•Where Possible, Avoid mutual redistribution at multiple points
•Configure administrative distance in such a way that each prefix native to each protocol or process is reached via the corresponding domain’s protocol or process.
•Control the prefixes (using distance or/and prefix-list / tag combination) in a way that the same prefix is not advertised back to the originating domain.
Hope it Helps..
-GI
