Spirent Studio Security has extensive functionality for testing routing (and related) protocols:
Protocol Fuzzing:
DoS (Denial-of-Service) module has a number of predefined templates that would be relevant to testing routers.
Studio Security Verify can test attributes within routing protocols (i.e., BGP, IEEE 802.1Q with all possible VLAN and priority tags, etc.). Spirent Studio Security was not designed to test aspects of networking protocols where there are timing-sensitive aspects of the protocol exchanges. Other Spirent products can be used for that kind of testing.