Overbooking, WS-X4640-CSFP-E

[jorel83]

Hi peeps,

I work as a Senior Network Engineer at a metro network, and unfortunately we have a bunch of WS-X4640-CSFP-E cards in 4506E chassies with CSFP optics hence 4:1 overbooking, and to add to the horrible problem its actually on distribution level so we have zero control of the situation with overbooking on these cards, and since its a Layer 2 network and L2-garbage traffic flows in "big" L2-areas is problematic.

I tried to find information on queues or if there is any way to see fabric utilization on the Cisco 4506E chassie (sup7L, 7LE, 8 etc). Is there any way on this platform to actuallty see whats going on in the utilization part of this equipment?

No its not my design and it was a horror to find out, but it became my problem to deal with.

Thanks for any suggestions.

[Collin Clark]

'show platform ...' should give you lots of good info on how the switch is performing.

HTH

[jorel83]

Hello,

sh platform, perhaps it will work, know any specifics on the 4500E platform? As you probably know, that command is notoriously tricky to actually get right information and then interpret it is many times more difficult due to lack of documentation (as far as I´ve experienced). I have so far not found a way to actually see the line card utilization in relation to backplane and neither no information on how the asics is grouped etc.

Basically i want something like this for the 6880 platform: https://ciscointerworking.wordpress.com/2015/06/14/asic-redundancy/

sh port capabilities gives no indication on ASIC/groupings, I assume its wirespeed on the linecard inbetween ports but i don't take it for granted.

sh platform mapping ports indicates under PortSet that first 5/1-48 ports on these cards is 3 (asic 3?) then next 5/49-80 is in PortSet 13 (asic 13) so here it would be necessary to find out if Asic 3 is overloaded at some point at 1 min intervall or less (we have issues with micro bursts of 120k frames/s that is difficult to filter out).

Cmds: sh controllers, sh controllers utilization, sh tcam count, sh platform tcam utilization don't work or dosen´t exist. show platform hardware acl statistics utilization brief, is in the right direction but too unspecific.

(rant): So imagine a having a switch with 2-5 80 ports cards limited overbooked 4:1 and for some obviously stupid reason the overbooked ports act upstreams for access-switches in relation to micro bursts and other traffic very high volume frames and QoS can't handle the priority so there are disruptions on multicast/unicast/voip streams. Only real solution seems to rebuild the network with other than Cisco equipment so we don't have overbooking or backplane congestion and access-switches with simple stuff as err-disable recovery dualspeed uplinks (1/10G), but thats a different story.

Bascially its important to find out when backplane or asic is overloaded to identify areas to rebuild or prioritized to fix and to be sure it is an issue at all, right now its just a resonable assumption.

Thanks for your suggestions :-)

[Collin Clark]

Have you checked out Troubleshooting Cisco Catalyst 4500 Series Switches - BRKCRS-3142 from Cisco Live!? If not, you can access it at www.ciscolive.com. It has some really good troubleshooting info in it. There's also BRKARC-3445 which shows how the 4500E is designed from a hardware perspective.

[Joseph W. Doherty]

What about using port utilization?

[Matt Delony]

Hello jorel830430,

There's no CLI command to show backplane utilization like on cat6k.

Interface input overruns would be a symptom of linecard oversubscription. Also look for overruns on the "show platform software interface x/y stub statistics" command. This will show stats for stub ASIC.