[c-nsp] GigE Throughput on 3825

[Seth Mattinen]

On 7/29/2010 15:07, Paul Stewart wrote:
> We have several in production but have never pushed them to their limits.
> One that comes to mind is a 3825 with max memory/max flash - it's going DHCP
> services to 1200 students in a university residence, handing off a few meg
> of voice traffic to those students and running two full BGP tables providing
> IP Transit at 100 meg peak to the university as well. Nothing really fancy
> but the CPU never peaks above 9% on average.
> 
> Another 3825 is currently running as a POP router handling about 130Mb/s of
> peak traffic, runs a good size OSPF table and has 16 port Gig card fully
> populated with each port doing routing.  Peak CPU is 11% average on that
> box.
> 
> I have seen some customers push them with 300-400Mb/s of traffic but am not
> sure how they really handled at that point - whether or not the CPU is
> pushing it or not.  Cisco 7206VXR with NPE-2G comes to mind if you don't
> want any hassles with higher traffic levels - of course you're into higher
> budget too ;)
> 


It's all CPU on an ISR or 7200. What matters is the packet size. It can
handle flows with large packets beyond what Cisco would officially
recommend them for (i.e. a file transfer), but throw a lot of tiny UDP
at it you'll quickly run out of headroom far below what you would expect.

~Seth