North American Network Operators Group
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Re: Scalability issues in the Internet routing system

  • From: Blaine Christian
  • Date: Wed Oct 26 16:49:41 2005 




I did read your comment on BGP lending itself to SMP. Can you
elaborate on where you might have seen this? It has been a
pretty monolithic implementation for as long as I can remember.
In fact, that was why I asked the question, to see if anyone had
actually observed a functioning multi-processor implementation of
the BGP process.





I can make the SMP statement with some authority as I have done the
internal

design of the OpenBGPd RDE and my co-worker Claudio has implemented
it. Given

proper locking of the RIB a number of CPU's can crunch on it and
handle neighbor

communication indepently of each other. If you look at Oracle
databases they

manage to scale performance with factor 1.9-1.97 per CPU. There is
no reason

to believe we can't do this with the BGP 'database'.





Neat! So you were thinking you would leave the actual route
selection process monolithic and create separate processes per peer?
I have seen folks doing something similar with separate MBGP routing
instances. Had not heard of anyone attempting this for a "global"
routing table with separate threads per neighbor (as opposed to per
table). What do you do if you have one neighbor who wants to send
you all 2M routes though? I am thinking of route reflectors
specifically but also confederation EIBGP sessions.



I think you hit the nail on the head regarding record locking. This
is the thing that is going to bite you if anything will. I have
heard none of the usual suspects speak up so I suspect that either
this thread is now being ignored or no one has heard of an
implementation like the one you just described.