[86210] in North American Network Operators' Group
Re: Scalability issues in the Internet routing system
daemon@ATHENA.MIT.EDU (Blaine Christian)
Wed Oct 26 14:56:42 2005
In-Reply-To: <435FC580.6020304@nrg4u.com>
Cc: nanog@nanog.org
From: Blaine Christian <blaine@blaines.net>
Date: Wed, 26 Oct 2005 14:56:22 -0400
To: Andre Oppermann <nanog-list@nrg4u.com>
Errors-To: owner-nanog@merit.edu
>
>> Another thing, it would be interesting to hear of any work on
>> breaking the "router code" into multiple threads. Being able to
>> truly take advantage of multiple processors when receiving 2M
>> updates would be the cats pajamas. Has anyone seen this? I
>> suppose MBGP could be rather straightforward, as opposed to one
>> big table, in a multi-processor implementation.
>>
>
> You may want to read this thread from the beginning. The problem
> is not
> the routing plane or routing protocol but the forwarding plane or
> ASIC's
> or whatever. Both have very different scaling properties. The
> forwarding
> plane is at an disadvantage here because at the same time it faces
> growth
> in table size and less time to perform a lookup . With current
> CPU's you
> can handle a 2M prefix DFZ quite well without killing the budget.
> For the
> forwarding hardware this ain't the case unfortunatly.
Hi Andre...
I hear what you are saying but don't agree with the above statement.
The problem is with the system as a whole and I believe that was the
point Vladis, and others, were making as well. The forwarding plane
is only one part of the puzzle. How do you get the updates into the
forwarding plane? How do you get the updates into the router in the
first place and how fast can you do that? I have seen at least one
case where the issue did not appear to be the ASICs but getting the
information into them rapidly. If you go and create a new ASIC
without taking into account the manner in which you get the data into
it you probably won't sell many routers <grin>.
BTW, I do agree that spinning new ASICs is a non-trivial task and is
certainly the task you want to get started quickly when building a
new system.
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.
Regards,
Blaine
