[c-nsp] 10 Mb internet traffic on a 3640?

[Bill Wichers]

> Hello All,
> I am working on a project where I will need to be running a minimum of
> 10 Mb of internet traffic 24 hours a day through a router with plans
> of expansion in the future.  I was wondering if a CISCO3640 will be
> able to handle my current bandwidth as well as our future needs.  If
> you do not think it will do the trick then your recommendations would
> be greatly appreciated.  Also, for future reference how would I be
> able to determine the bandwidth limitations of a router just by
> looking at the kpps limitations and CPU speed?

You really need to provide more info than that to make an accurate
determination of what you'll need. If you will be using the router in a
"CPE-like" role, where everything either goes out a default route or in to
one netblock, then a 3640 will easily handle it. If you plan to be
multihomed and take a BGP feed, or run lots of filters or tunnels (or any
other thing where the router has to think about the traffic), then you
might need more.

Packets per second is usually only an issue if you're running some app
that generates lots of small packets, or when you are getting hit with a
DDoS. You probably won't run into pps limitations in a simple setup. Most
of the traffic you see that uses a large percentage of your bandwidth is
likely to be at or near to MTU size packets. CPU speed becomes an issue
when you start running any fancy stuff like ACLs or lots of traffic
shapers -- basically anything beyond "this packet goes there" type stuff.

I am inclined to say you'll probably be safe with the 3640 though. We had
a 2621 in a basic ethernet-to-ethernet application with everything default
routed and it handled many megabits with ease -- but we didn't do anything
except ICMP rate limiting on it, in addition to the usual basic routing.

     -Bill

*****************************
Waveform Technology
UNIX Systems Administrator