Cisco Intelligent WAN (IWAN)

Appendix A. Dynamic Multipoint VPN Redundancy Models

DMVPN provides two of forms of NHS redundancy. Although the IWAN prescriptive model supports only the NHRP clusterless model, the authors wanted to demonstrate both models to provide a better understanding.

NHRP Clusterless Model

The NHRP clusterless model places all NHS routers in the same cluster, assigns preference by priority, and restricts the maximum number of active connections to an NHS. This model presents a possible configuration where an NHS hub is not present at a specific site.

For example, assume that six hub routers are distributed equally across three data centers. The design states that an NHC maintains an active connection to only three NHS routers at a time, and that a ...