[cisco-bba] L2TP sessions on 7200

[Dennis Peng]

Anastassios Chatzithomaoglou [achatz at forthnet.gr] wrote:
> 
> 
> 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?

You can't clear these statistics, so the only way to tell the rate at
which you are getting fragments is to get two snapshots of "show ip
traffic" and see what the delta is compared to the time differential.

Dennis

> 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>
> ***********************************
> 
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