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RE: CIsco 7206VXR w/NPE-G1 Question

  • From: Michel Py
  • Date: Sat Jan 31 00:51:35 2004

>> Michel Py wrote:
>> That would be where the NPE-G1 would be better than an RSP8; 

> [email protected] [mailto:[email protected]] 
> Isn't it somewhat wrong to compare the NPE-G1 to any RSP
> since most of the packets, most of the time, are handled
> by the processors on the VIPs and never bother the RSP

In general, yes indeed. However, you have to place it in the same
context as I did, quoted below:

>>> [email protected] wrote:
>>> flow-based means router's performance is based on number
>>> of flows established, and first packet of each 'flow' is
>>> processed differently [slower] from all other within the
>>> flow, and things like nachi will kill it.

>> Michel Py wrote:
>> That would be where the NPE-G1 would be better than an RSP8;

In this very case, where a large part of the traffic is a shitload of
new flows, dCEF is irrelevant and the NPE-G1 has indeed an advantage
over any RSP because it has a 700Mhz processor and the RSP16 is 400Mhz
and the RSP8 250Mhz. Of course, this assumes that you are actually doing
flow-based routing, which I don't see being that common among ISPs.


> If you take a 7500 as far as you can (RSP16, VIP6-80s),
> then how does it compare to a 7206VXR/NPE-G1?

Ah that's an interesting academic question, and although I will take a
shot at it,
1. The question is vague.
2. #include <disclaimer.h>
3. Can't really be answered without testing it.
4. Even when actually testing it with real traffic, your mileage may
vary as the traffic patterns being used can indeed greatly the results.

That being said, here's my take at it:

We have on one side
7206VXR with NPE-G1 and 6x PA-POS-OC3 (or similar)

And on the other:
7507MX with RSP16, 3x VIP6-80, 6x PA-POS-OC3 (or similar), 2x GEIP
[ this setup is flawed in the first place, as the GEIP is based on
the VIP2-50; the correct setup should be:
7507MX with RSP16, 4x VIP6-80, 6x PA-POS-OC3 (or similar), 2x PA-GE.
Unfortunately, the VIP6-80 does not support the PA-GE :-( ]

On each router: two of the GigE are connected to tier-1 transit, and the
DS3s to either big customer or remote pop.

I call this a draw. On one hand, if the traffic between the two GigE is
not well balanced, the 7507 has a problem with the throughput of the
GEIP.

On the other hand, the NPE-G1 has a 700 Mhz CPU, but has to deal with
all of the following:
  - two GigE
  - six PAs
  - BGP and flows

where the 7507 has:

  - 2x 200Mhz VIP2-50 for the GigE
  - 3x 400Mhz VIP6-80 for the PAs
  - 1x 400Mhz RSP16 for BGP and flows

My take is: in some situations, the 7507 will be better and in some
others the 7206 will be better. The weak point of the 7507 setup is the
GEIP, the weak point of the 7206 is that is has only one CPU.

Now, _if_ in the 7507 you could replace 2x GEIP with 1x VIP6-80 + 2x
PA-GE, I would give a clear advantage to the 7507 setup. In any case, a
7600 will beat the crap out of any 7200.

Michel.