Fw: [c-nsp] A Stable BRAS IOS? + performance

[Brad Bonin]

Without looking at the config or processes, it could be a number of things including the way you handle routing.  May be best to
open a TAC case and let them review your config/processes/memory usage.

I think the best place to be is 12.3 mainline, which supports G-1.  12.3T provides some enhancements, especially if SSG is used.  If
you just need the basics (L2TP, PPP termination, etc.), then stick with 12.3.  The end game is to go to 12.3 GD when it is
available.

brad at cisco.com 

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Osama I. Dosary
Sent: Monday, December 06, 2004 8:01 AM
To: cisco-nsp at puck.nether.net
Subject: Re: Fw: [c-nsp] A Stable BRAS IOS? + performance

Thanks Gyebnár,
But we are using a keepalive of 60 seconds!
Could it be the fragmentation that is causing low performance?
How can I tell?
"sh ip traffic" gives absolute values. What is a high fragmentation rate or percentage?
#sh ip traffic Output:
IP statistics:
  Rcvd:  206704290 total, 58613783 local destination
         7947 format errors, 7 checksum errors, 79 bad hop count
         0 unknown protocol, 35440 not a gateway
         0 security failures, 0 bad options, 12419 with options
  Opts:  0 end, 0 nop, 0 basic security, 0 loose source route
         0 timestamp, 0 extended security, 0 record route
         0 stream ID, 0 strict source route, 12419 alert, 0 cipso, 0 ump
         0 other
  Frags: 276689 reassembled, 575 timeouts, 0 couldn't reassemble
         9383185 fragmented, 0 couldn't fragment

Gyebnár Krisztián wrote:

>
> Hi,
>
> We running on 12.3.10a on our NPE-G1 without any problem, the
> performance:
> ~3000 users, no fragmantation(fully 1552 byte MTU path from the LAC to
> LNS)
> 250Mbit/sec bidirectional taraffic and the cpu about 55-60%, also only 
> L2TP and PPP session termination is going on.
>
> Important: check the keepalive time because the default is 10 seconds 
> :-(, this cause many overhead on the Network, CPU...
> we set up this to 30s and the performance is much better :-)
>
> Krisztián
>
>> ----- Original Message ----- From: "Osama I. Dosary" 
>> <oid at saudi.net.sa>
>> To: <cisco-nsp at puck.nether.net>
>> Sent: Monday, December 06, 2004 7:50 AM
>> Subject: Re: [c-nsp] A Stable BRAS IOS? + performance
>>
>>
>>> Robert E.Seastrom wrote:
>>>
>>>> "Osama I. Dosary" <oid at saudi.net.sa> writes:
>>>>
>>>>
>>>>> Hello,
>>>>>
>>>>> We are using Cisco routers (NPE-G1) as a NAS and LNS. No PVCs are 
>>>>> terminated on these routers, only L2TP and PPP session termination 
>>>>> is going on.
>>>>>
>>>>> We have having difficulting finding a stable IOS to run on these 
>>>>> routers.
>>>>>
>>>>> Does anyone know of a good stable IOS they have been using for the 
>>>>> same/similar purpose, and recommend?
>>>>>
>>>>
>>>> I've been using c7200-js-mz.123-8.T4.bin for about six weeks now as 
>>>> an LNS; while it's not GD it runs quite nicely on an NPE300 and I 
>>>> believe will run on your G1 as well.  Our load peaks at a little 
>>>> over 1600 simultaneous users, 55% CPU, 50 Mbit aggregate (up + 
>>>> down) traffic through router (your mileage will obviously vary 
>>>> since you have a much more studly CPU).  CPU load is slightly 
>>>> inflated because of outstanding issues with a few hosts that are 
>>>> moving oversized L2TP packets that get fragmented and need 
>>>> reassembly to pop the PPPoE frame (fragment reassembly is most 
>>>> assuredly *not* in the fast switching path).
>>>>
>>>>
>>> On our NPE-G1 (for Dialup) load peaks at ~3000 users, 110Mbps 
>>> (up+down) traffic and CPU util is about 80%. I feel like we are 
>>> doing something wrong, according to Cisco docs, this router should 
>>> be able to handle tons more.
>>>
>>> Even when we used to run NPE-300s for dialup, it could not handle 
>>> more than 900 sessions, with CPU over 90%. What could be the reason?
>>> We used various IOS versions, without much difference in 
>>> performance. We noticed that when the B-train version is used we 
>>> save about 5-10% on CPU cycles. But it is still far from the router 
>>> specifications.
>>>
>>> Could this be a matter of fragmentation of the L2TP packets that 
>>> could be causing bad performance.
>>> Any ideas?
>>>
>>>
>>> -Osama
>>>
>>>
>>>
>>> _______________________________________________
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>>
>
>
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