Controlling BGP Route Aggregation
The Junos OS implementation of BGP performs route aggregation, which is the process of combining the characteristics of different routes so that only a single route is advertised. Aggregation reduces the amount of information that BGP must store and exchange with other BGP systems.
BGP adds the aggregator path attribute to BGP update messages. This attribute contains the local system’s AS number and IP address (router ID).
To prevent different routers within an AS from creating aggregate routes that contain different AS paths, set the IP address in the aggregator path attribute to 0 by including the no-aggregator-id statement:
For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.
