[cisco-bba] L2TP sessions on 7200

[Anastassios Chatzithomaoglou]

Vincent Fayet (vfayet) wrote:
> Not only the number of session and the dis/connection is important but
> also the rate (pps) per active session is quite important.
> 

We have pstn 56 and isdn 64/128 customers terminating on this router, using an average of 
8-10pps for each active session. But nearly half of all sessions are sitting idle.

> I imagine you have already checked any issue regarding fragmentation and
> probably you already use the adjust-mss feature.
> 

How do i check for any fragmentation issues?
Does the following command provide any usefull info and how do i clear the statistics?

router#sh ip traffic
IP statistics:
   Rcvd:  72240344 total, 2143924 local destination
          359 format errors, 20 checksum errors, 1148 bad hop count
          0 unknown protocol, 0 not a gateway
          0 security failures, 0 bad options, 3907 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, 3907 alert, 0 cipso, 0 ump
          0 other
   Frags: 654631 reassembled, 162 timeouts, 0 couldn't reassemble
          8098104 fragmented, 8 couldn't fragment
   Bcast: 39861 received, 0 sent
   Mcast: 1276402 received, 30849 sent
   Sent:  404825 generated, 66810550 forwarded
   Drop:  326 encapsulation failed, 179 unresolved, 0 no adjacency
          54200 no route, 0 unicast RPF, 0 forced drop

Also, configuring "ip tcp adjust-mss 1420" under the vtemplate doesn't seem to make any 
big difference (maybe 5% down). But i'm worrying for any client problems that may arise 
from such a change.

> Cheers
> 
> Vincent
> 
> ------------------------------------------------------------------------
> ---------------
> Vincent Fayet
> Systems Engineer
> Cisco Systems
> ------------------------------------------------------------------------
> ---------------
> 
> 
> 
>>-----Original Message-----
>>From: sthaug at nethelp.no [mailto:sthaug at nethelp.no] 
>>Sent: vendredi 25 juillet 2003 13:20
>>To: achatz at forthnet.gr
>>Cc: cisco-bba at puck.nether.net
>>Subject: Re: [cisco-bba] L2TP sessions on 7200
>>
>>
>>
>>>I have read a lot of conversations about 7200 and the max 
>>
>>number of l2tp sessions it can 
>>
>>>support, but all the answers are making me think that there 
>>
>>is something wrong with my 
>>
>>>case. My router doesn't even seem capable of reaching 1000 sessions.
>>>
>>>I have a 7206 (NPE-300) and with 550 sessions it reaches 
>>
>>50% - 60% cpu load.
>>
>>>Is there anything i can do in order to decrease it?
>>>"ip cef" doesn't seem to do anything...
>>
>>We found when doing L2TP termination that there's a big difference
>>between the number of L2TP sessions you can handle in the 
>>steady state,
>>and the number you can handle when you have a lot of signaling (L2TP
>>sessions going up & down). The signaling traffic seems to 
>>chew up a lot
>>of CPU.
>>
>>Steinar Haug, Nethelp consulting, sthaug at nethelp.no
>>_______________________________________________
>>cisco-bba mailing list
>>cisco-bba at puck.nether.net
>>http://puck.nether.net/mailman/listinfo/cisco-bba
>>
> 
> 

-- 
***********************************
    Chatzithomaoglou Anastasios
Network Design & Operations Center
           FORTHnet S.A.
       <achatz at forthnet.gr>
***********************************