More about the creation
of routing sessions
The creation of BGP sessions
and
The creation of OSPF neighbor
relationships provide insight into how
creates routing sessions between routing-protocol
neighboring endpoints.
The creation of BGP
sessions

The creation of
OSPF neighbor relationships

The creation of BGP sessions
and
The creation of OSPF neighbor
relationships show that in an overlapping IP environment, where one or
more discovered routing devices contain overlapping IP addresses,
observes the following rules to ensures that it creates
the correct routing sessions in its modeled topology:
- For a BGP endpoint layered over a tagged IP that has a tag value of xxx, will create a BGP session to a neighboring BGP endpointif and only ifthat endpoint is also layered over a tagged IP that has a tag value of xxx.
- For an OSPF endpoint layered over a tagged IP that has a tag value of yyy, will create an OSPF neighbor relationship to a neighboring OSPF endpointif and only ifthat endpoint is also layered over a tagged IP that has a tag value of yyy.In addition, to observe the rule in the second bullet item, will create OSPF subareas for an OSPF area 0. The describes a situation in which creates five subareas for an OSPF area 0. The creation of OSPF neighbor relationships also helps explain OSPF subareas: An OSPF subarea consists of OSPF interfaces that are layered over tagged IPs that have the same tag value.creates afull linkfor an adjacency connection if both routing-protocol endpoints are in the managed topology. creates ahalf link(a stub adjacency) for an adjacency connection if only one routing-protocol endpoint is in the managed topology.For any device placed on the Pending Elements list during the discovery, will attempt to discover that device during the next pending discovery. Pending discovery is described in Chapter 6, “Invoking Full or Pending Discovery.”