During the postprocessing phase of discovery, MPLS Manager creates an “UnderlyingVPN” relationship between the discovered BGP services/ BGP protocol endpoints/ BGP sessions and the VPNs that are discovered during L3VPN discovery:
- BGPService - UnderlyingVPN ->VPN
- BGPProtocolEndpoint - UnderlyingVPN ->VPN
- BGPSession - UnderlyingVPN ->VPN
The UnderlyingVPN relationship is what makes MPLS-BGP cross-domain correlation possible. It enables MPLS Manager to generate VPN-impacted events for underlying BGP sessions that are impacted by BGP failures, misconfigurations, or manually disabled BGP protocol endpoints.
Like MPLS-IP cross-domain correlation, MPLS-BGP cross-domain correlation requires the use of the Global Manager to complete the cross-domain impact analysis. The Global Manager examines the problems and impacts from MPLS Manager and Network Protocol Manager for BGP to learn the explanation chain, and then adds the VPN impact as an impact of the underlying BGP problem.
Because some BGP objects are updated more frequently in Network Protocol Manager for BGP than in MPLS Manager, the BGP topology in MPLS Manager might differ from the BGP topology in Network Protocol Manager for BGP. When differences occur, resynchronize the two topologies by invoking Discover All in both Managers.