[c-nsp] GSR with STM-4 and packet loss, weird LC cpu utilization etc.

[Ibrahim Abo Zaid]

Dear Primoz

it is really a weird problem but it needs more isolation steps , regarding
the CRC point
CRC are counted at the fabric interface between LC and Fabric and that is
why it is not shown at the interface counters , you can check CRC errors
according to th below cisco links

http://www.cisco.com/warp/public/63/output_shcontfia.html
http://www.cisco.com/warp/public/108/hwts_12000_22281.html#ts_switchfabr



then we can look the processes utilizes the line cards CPU



best regards
Abo Zaid




On 11/30/07, Primoz Jeroncic <jp at softnet.si> wrote:
>
> Hi
>
> I have some weird problems on one of our STM-4 links. From time to time
> about 5-7 packets get lost on this link. It doesn't happen every
> X minutes/hours but randomly, and always with 5-7 packets in row. There's
> no CRC, input or output errors on any of ports, and also our carrier
> is trying to tell me, everything is fine on their link. Overall, packet
> loss is about 0.2 to 0.5% during longer period (1 day or more).
>
> So I went to check with routers. On both sides we are running GSR with
> 4 Port Packet Over SONET OC-12c/STM-4 SM line cards. So when I went to
> check, I found out, on one side, LC processor has 50-60% utilization,
> while on other it has 3-4% utilization (on both sides it's constantly
> at such percentage). I still don't think this packet loss would be
> connected to "high" (50-60%) utilization, since if it would be, I would
> have this packet loss contantly, not just few packets every few hours.
> And it's also not fully utilized port either. Average throughput is
> about 400Mbps, while peaks never go over 500Mbps.
>
> So now I have 2 questions. First... does anyone have any idea what could
> be reason for such packet loss?
>
> And second... And idea why one LC would be at 3-4%, while other would
> be at 50-60%? Both LCs are same, both routers are same, and even config
> on both LCs is same... see below:
>
> Diags are same for both, except one is in slot 1, while other is in slot
> 6:
>
> SLOT 1  (RP/LC 1 ): 4 Port Packet Over SONET OC-12c/STM-4 Single Mode
> FRU:  Linecard/Module: 4OC12/POS-IR-SC-B=
>        Route Memory: MEM-GRP/LC-256=
>        Packet Memory: MEM-LC1-PKT-256=
> L3 Engine: 2 - Backbone OC48 (2.5 Gbps)
> DRAM size: 268435456 bytes
> FrFab SDRAM size: 134217728 bytes, SDRAM pagesize: 8192 bytes
> ToFab SDRAM size: 134217728 bytes, SDRAM pagesize: 8192 bytes
>
>
> Config on port:
> Location 1 (utilization 50-60%):
> interface POS6/0
> bandwidth 622080
> ip address x.x.x.1 255.255.255.252
> no ip redirects
> no ip unreachables
> no ip directed-broadcast
> encapsulation ppp
> ip route-cache flow sampled
> load-interval 30
> tag-switching mtu 1546
> tag-switching ip
> crc 16
> clock source internal
> pos framing sdh
> pos flag s1s0 2
>
> Location 2 (utilization 3-4%)
> interface POS1/0
> bandwidth 622080
> ip address x.x.x.2 255.255.255.252
> no ip redirects
> no ip unreachables
> no ip directed-broadcast
> encapsulation ppp
> ip route-cache flow sampled
> load-interval 30
> tag-switching mtu 1546
> tag-switching ip
> crc 16
> clock source internal
> pos framing sdh
> pos flag s1s0 2
>
> Only difference betwen boxes is IOS. On Location 1, we are running
> service provider ios 12.0(30)S5, while on Location 2 we are running
> 12.0(26)S5.
>
> And help, tips, suggestions are more then welcome :)
>
> Thanks for help.
>
> Have fun,
> Primoz Jeroncic
> Support - IP Connectivity & Routing
> -------------------------------------------------------------------
> Softnet d.o.o.  tel:  +386 1 562 31 40   |
> Borovec 2       fax:  +386 1 562 18 55   |       1 + 1 = 3
> 1236 Trzin      primoz(at)softnet.si     | for larger values of 1
> Slovenija       http://flea.softnet.si/
> -------------------------------------------------------------------
>
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>