ospf-5----Page:23
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
|
Summary of Features A scalable CDS algorithm (and family of interoperable CDS algorithms) is proposed, which generalizes the OSPF concept of a DR and BDR in a natural way. The set of DRs forms a CDS, and the set of DRs and BDRs forms a biconnected CDS for robustness. The number of DRs and BDRs, the number of adjacencies, and the rate at which new adjacencies are formed, are all found to be scalable in simulations. The CDS algorithm uses only 2-hop neighbor information from differential Hellos, allowing fast convergence following topology changes. Only partial 2-hop neighbor information is required. Thus, a non-DR/BDR router never needs to include all of its neighbors in either a Hello or an LSA. The computed CDS provides source-independent flooding of LSAs (or other packets). The flooding procedure also allows source-dependent flooding as an option, if it is desired to flood packets along min-hop paths. The choice of which neighbors to include in LSAs is flexible, allowing dissemination of partial or full topology information. |