[c-nsp] Your opinions on router throughput

Ted Mittelstaedt tedm at toybox.placo.com
Fri Oct 27 00:48:03 EDT 2006


OK here's the scenario:

2 Cisco 7206 VXR's.  First one has 3 high speed interfaces, a FE to
the local LAN that has customer connections, a FE running 30Mbt to
one Internet feed, and a PA-A3-T3 that is running 45Mbt to the second VXR

The second VXR has 3 high speed interfaces, a FE to the local LAN that
has customer connections, a PA-A3-T3 going to 10Mbt-burst-to-45Mbt Internet
feed,
and a PA-A3-T3 going to the first VXR  The PA-A3-T3 cards are
on a point-to-point DS3 and were used instead of regular serial DS3
cards because they had them around.

Both VXR's have NPE300 with 256MB of ram.  Both are running
iBGP between themselves, and eBGP to the feeds and receiving a full
BGP table from the feeds.  IOS is 12.2

Right now everything is happy and there's no problems.  But, utilization
on the feeds is nowhere near max.

The question put to us was,

Is there a chance of the NPE300's running out of horsepower
as throughput on the setup increases to the maximum of each circuit?  There
are customers on the LAN side that could, if all bandwidth limiting
was removed, saturate either the 10Mbt-burst-to-45Mbt, or the 30Mbt ethernet
feed, or the 45Mbt interconnect between routers.

I told them to try it and see what happens. :-)  That didn't go over
very well.

My gut is that this setup, while it may run utilization up past 60%
at full bore, will pass muster.  Certainly the chassis of the 2 routers
will, but I am unsure of the real-world expectations of an NPE300.
(as opposed to the published specs)

They are running ip cef.  They know that the NPE300 is
obsolete but there is nothing in the newer IOS that they want.

Comments and speculations welcome.

Ted



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