Chapter 9. Other Large Scale Cores

Scalability of full mesh, Layer 3 designs is a major issue when building very large networks. Chapter 3, "Redundancy," discussed problems with Layer 2, full mesh designs. Layer 3, full mesh designs have many of the same problems.

At some point, the number of possible neighbors and paths becomes overwhelming, and you need to reduce the amount of work that needs to be done by the core routers.

Two possible solutions to this problem are Next Hop Resolution Protocol (NHRP) and Multiprotocol Label Switching (MPLS).