[c-nsp] FW: Overruns

[Emanuel Popa]

Sorry. I'm not very familiar with that kind of linecards. Only using
LAN cards 67xx with DFC modules.

However, when we encountered overruns we had 2 options:

1. easy one: enable "fabric clear-block"; this will get rid of
overruns but will drop packets in fabric which is gonna be harder to
detect; the fabric is only going to internally prioritize CoS 5 with
older IOS versions; with newer versions might be another story; never
tested though

2. more difficult: "ingress queuing" is necessary to overrun only
packets you afford to drop, but can be done only with CoS and 802.1q
configured on your ether-channels

Anyways, is there any congestion at the egress in your router that is
causing the overruns in the first place? Or is this a different
problem than what we experienced?

Regards,
Manu


2010/5/5 Mohammad Khalil <eng_mssk at hotmail.com>:
> The cards are SFM-capable 48 port 10/100/1000mb
> we connect 10 connections from each router to the ASN , each 5 are grouped
> together , 5 for VLAN that handle RAS to ASN communication and the other 5
> to handle ASN to Core communication
>
>> Date: Tue, 4 May 2010 23:50:31 +0300
>> Subject: Re: [c-nsp] FW: Overruns
>> From: emanuel.popa at gmail.com
>> To: eng_mssk at hotmail.com
>> CC: cisco-nsp at puck.nether.net
>>
>> hi mohammad,
>>
>> what kind of linecards are you using? what capacity? how many links
>> per ether-channel?
>>
>> we had similar problems with overruns at ingress because of egress
>> congestion. there are different workarounds for each setup. all
>> problems are related to buffers and fabric connections though.
>>
>> regards,
>> manu
>>
>>
>> 2010/5/4 Mohammad Khalil <eng_mssk at hotmail.com>:
>> >
>> > hi all
>> >
>> > i posted this issue earlier but didnt get a solution
>> > anyway the MTU settings from both side are the same 1500 bytes
>> > i dont think that the MTU modification from Cisco side as its related to
>> > the number of packets sent from the ASN side and received by the Cisco side
>> > i was viewing the buffers on the Cisco side and found below
>> > Public buffer pools:
>> >
>> > Huge buffers, 18024 bytes (total 2, permanent 2, peak 11 @ 5w5d):
>> >     2 in free list (0 min, 4 max allowed)
>> >     10062 hits, 182 misses, 364 trims, 364 created
>> >     0 failures (0 no memory)
>> >
>> > do the misses number indicate anything ??
>> > does the buffer tuning will solve the issue ?
>> > even the IOS upgrade didn't solve the issue
>> >
>> > Thanks
>> >
>> > From: eng_mssk at hotmail.com
>> > To: cisco-nsp at puck.nether.net
>> > Subject: Overruns
>> > Date: Tue, 6 Apr 2010 11:44:46 +0300
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> > hi all
>> >
>> > i have 2 cisco 7606 routers connected to ASN GW for wimax traffic
>> > we had a problem with overruns on the port channels
>> > we connected 5 cables from the ASN to both routers and configured port
>> > channels for VLAN and the same setup for another vlan
>> > one vlan is for communcations with RASs and one to transport the traffic
>> > for into the core cloud
>> > anyway we upgraded the IOS version on the routers thinking thats might
>> > solve the issue but still
>> > please find below
>> >
>> > CR1.KJ-Building#sh int po10 | inc over
>> >     1 input errors, 1 CRC, 0 frame, 72395 overrun, 0 ignored
>> > CR1.KJ-Building#sh int po20 | inc over
>> >     6 input errors, 2 CRC, 0 frame, 734930 overrun, 0 ignored
>> >
>> > CR1.KJ-Building#sh run int po10
>> > Building configuration...
>> >
>> > Current configuration : 259 bytes
>> > !
>> > interface Port-channel10
>> >  description CORE_VLAN to ASN Gateway
>> >  switchport
>> >  switchport access vlan 10
>> >  switchport trunk encapsulation dot1q
>> >  switchport mode access
>> >  load-interval 30
>> >  speed 1000
>> >  duplex full
>> >  flowcontrol receive on
>> >  flowcontrol send on
>> > end
>> >
>> > CR1.KJ-Building#sh run int po20
>> > Building configuration...
>> >
>> > Current configuration : 258 bytes
>> > !
>> > interface Port-channel20
>> >  description RAS-VLAN to ASN Gateway
>> >  switchport
>> >  switchport access vlan 20
>> >  switchport trunk encapsulation dot1q
>> >  switchport mode access
>> >  load-interval 30
>> >  speed 1000
>> >  duplex full
>> >  flowcontrol receive on
>> >  flowcontrol send on
>> > end
>> >
>> > CR2.KJ-Building#sh int po10 | inc over
>> >     0 input errors, 0 CRC, 0 frame, 17889 overrun, 0 ignored
>> > CR2.KJ-Building#sh int po20 | inc over
>> >     0 input errors, 0 CRC, 0 frame, 826604 overrun, 0 ignored
>> >
>> > CR2.KJ-Building#sh run int po10
>> > Building configuration...
>> >
>> > Current configuration : 259 bytes
>> > !
>> > interface Port-channel10
>> >  description CORE_VLAN to ASN Gateway
>> >  switchport
>> >  switchport access vlan 10
>> >  switchport trunk encapsulation dot1q
>> >  switchport mode access
>> >  load-interval 30
>> >  speed 1000
>> >  duplex full
>> >  flowcontrol receive on
>> >  flowcontrol send on
>> > end
>> >
>> > CR2.KJ-Building#sh run int po20
>> > Building configuration...
>> >
>> > Current configuration : 258 bytes
>> > !
>> > interface Port-channel20
>> >  description RAS-VLAN to ASN Gateway
>> >  switchport
>> >  switchport access vlan 20
>> >  switchport trunk encapsulation dot1q
>> >  switchport mode access
>> >  load-interval 30
>> >  speed 1000
>> >  duplex full
>> >  flowcontrol receive on
>> >  flowcontrol send on
>> > end
>> >
>> > any advice in regards
>> > thanks
>> >
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