11/12/2022 0 Comments Ospf network typesDR/BDR election How to discover neighbor(auto/manual).The following three points are determined by the network type. As for network types, it is enough to know only BROADCAST and POINT_TO_POINT. The information is stored in the link-state database, which is identical on all routers in the AS.Frame Relay/ATM is rarely used anymore. The LSA is forwarded only within the area it originated in and is flooded to all other routers in the area. The LSA contains a list of all recently seen routers and their costs. Note - If you need to connect two networks that both already have backbone areas and you do not want to reconfigure one to something other than 0.0.0.0, you can connect the two backbone areas using a virtual link.Įach router records information about its interfaces when it initializes and builds an LSA packet. If you have an area that is not connected to the backbone area, you can connect it by configuring a virtual link, enabling the backbone area to appear contiguous despite the physical reality. Note - The backbone area cannot be an NSSA area.īest Practice - Limit OSPF areas to about 50 routers based on the limitations of OSPF (traffic overhead, table size, convergence, and so on).Īll OSPF areas must be connected to the backbone area. NSSA border routers translate selected Type 7 LSAs into Type 5 LSAs, which can then be flooded to all Type-5 capable areas.īest Practice - Configure an area as an NSSA, if you want to reduce the size of the routing table, but still want to allow routes that are redistributed to OSPF. NSSA is an OSPF Stub Area, which can carry routes learned by other protocols such as BGP or RIP.Īllows the import of external routes in a limited fashion using Type-7 LSAs. Note - The backbone area cannot be a stub area. Routes external to the OSPF domain are not added to the routing table. You can configure an area as a Stub Area to reduce the number of entries in the routing table. Stub areas do not allow Type 5 LSAs to be propagated into or throughout the area and instead depend on default routing for external destinations. Neither a Stub Area, nor a Not-So-Stubby Area. You can designate other areas, depending on your network design, of the following types: The backbone area has the identifier 0.0.0.0. You must specify at least one area in your OSPF network - the backbone area, which has the responsibility to propagate information between areas. LSAs do not leave the area from which they originated, thus increasing efficiency and saving network bandwidth. Routers using OSPF send packets called Link State Advertisements (LSA) to all routers in an area.Īreas are smaller groups within the AS that you can design to limit the flooding of an LSA to all routers.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |