Re: BGP / Zebra

[Russell Coker <russell@coker.com.au>]

On Fri, 11 Jan 2002 10:39, Anders Gjære wrote:
> I have a router running BGP / Zebra, and it seems like the maximum
> throughput is 25Mbit/s
>
> BGP and Zebra using 100% cpu together, and alternating on witch using
> most.

Presumably you mean that the bgpd and the zebra process use 100% CPU.

When you say that the maximum throughput is 25Mb/s, is that for routing or 
for BGP protocol?

Do the zebra and bgpd processes use any significant amount of CPU time when 
the system is not routing any data?  If there is no data being routed the 
zebra and bgpd processes will have to do the same amount of work.  So if 
stopping the routing decreases the apparent CPU usage of them then they are 
not really using CPU time.

When the kernel receives an interrupt for a network packet it will route it, 
and put the time taken to do so against it's count of the time used by the 
application that was running at the time of the interrupt.

For example, I was once running a rather slow workstation on a 10base2 
network that had a lot of Netware traffic which involved lots of small 
packets.  After accidentally putting the network interface into promiscuous 
mode the most trivial processes would appear to take 100% CPU time (of course 
the machine in question was a 486 with an ISA network card).

With a modern machine such as your P2-233, it should be able to route 100Mb/s 
easily if you have good network cards and firewall rules that aren't too 
complex.  I always use Tulip cards when given a choice, as they seem to be 
able to do a lot of work without using much CPU power.  But I'm not aware of 
any good survey of cards in this regard.

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