BGP Lab

Interesting things I discovered during the BGP Lab:

- when configuring "bgp router-id x.x.x.x" command on a BGP speaker that has a session with another BGP speaker, thet BGP session is torn down, and reestablished. In OSPF there was a need for "clear ip ospf process"

- when aggregating in BGP with "aggregate-address x.x.x.x mask y.y.y.y" the prefix that was generated has weight 32768, and has the ATOMIC-AGGREGATE (well-known discretionary) attribute present. This attribute states that during the aggregation some information was lost (e.g. AS_PATH information)

- when aggregating in BGP with "aggregate-address x.x.x.x mask y.y.y.y as-set" the prefix has an AS_SET made of all pe AS_PATH values (UNORDERED) in all the prefixes aggregated and, because no information was lost during aggregation, the ATOMIC-AGGREGATE attribute is no longer present.