[c-nsp] Your opinions on router throughput

[Ted Mittelstaedt]

Hi David,

  Interesting post, I knew there was overhead but I didn't realize
it was that much.  Although I disagree with the assertion that
as many packets are that small.

  The PA-A3-T3 cards were used because they had them -
question for you, Cisco PA HSSI cards are cheap and plentiful
on the used market, as are Kentrox 1591 T3 ISDU's - would
switching over to those reduce the overhead on a point-to-point DS3
enough to bother with?

Ted

----- Original Message ----- 
From: "David Freedman" <david.freedman at uk.clara.net>
To: <cisco-nsp at puck.nether.net>
Sent: Friday, October 27, 2006 5:15 AM
Subject: Re: [c-nsp] Your opinions on router throughput


> > 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.
> >
>
> You will also have to bear in mind the ATM overhead which will reduce
> the effective throughput of this solution
>
> See this old nanog post for more information (assume that PLCP is
> enabled by default)
>
> http://www.merit.edu/mail.archives/nanog/1997-03/msg00263.html
>
> I dont think much has changed here, unless the PA-A3 card has a way of
> doing this better....
>
>
> Dave.
>
>
> > 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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