First page Back Continue Last page Overview Text
Notes:
The MRAI timer is part of the base BGP4 specification. A perfect implementation would maintain one timer per route to determine whether a new BGP message can be sent, but this would consume lots of memory. As noted in the BGP4 specification :
Two UPDATE messages sent by a BGP speaker to a peer that advertise
feasible routes and/or withdrawal of unfeasible routes to some common
set of destinations MUST be separated by at least MinRouteAdvertise-
mentInterval. Clearly, this can only be achieved precisely by keeping
a separate timer for each common set of destinations. This would be
unwarranted overhead. Any technique which ensures that the interval
between two UPDATE messages sent from a BGP speaker to a peer that
advertise feasible routes and/or withdrawal of unfeasible routes to
some common set of destinations will be at least MinRouteAdvertise-
mentInterval, and will also ensure a constant upper bound on the
interval is acceptable.
For a discussion of the impact of the MRAI timer, see :
An Experimental Analysis of BGP Convergence Time. Timothy G. Griffin and Brian J. Premore. ICNP 2001.
http://www.cs.dartmouth.edu/~beej/pubs/icnp2001.ps