I am hoping some of you Cisco Nexus veterans out there could shed some light on this issue or provide some insight if this has been encountered before.
Has anyone had egress VQ Congestion issues on the Nexus 7k using F2e line cards causing input discards? There has been intentional influx of traffic over the past few months to these units (Primarily VoIP traffic) IE: SBCs and such. These SBCs are mostly 1G interfaces with a 10G uplink to the core router. At some point of traffic shift the switch interfaces facing the SBC accrue egress VQ congestion and input discards start dropping packets into the switches from the core router uplinks. We have opened a Cisco TAC ticket and they go through the whole thing about the Nexus design and dropping packets on ingress if the destination port is congestion, etc... and I get all that. They also say going from a 10G uplink to a 1G downlink is not appropriate however those downstream devices are not capable of 10G. They amount of traffic influx isn't that much (your talking 20-30M max of VoIP). We have removed Cisco FabricPath from all VDCs and even upgraded our code from 6.2.16 to 6.2.20a on the SUP-2E supervisors. I understand the N7K-F248XP-23E/25E have 288KB/Port and 256KB/SOC and I would think these would be more than sufficient. I know the F3248XP-23/25 have 295KB/Port 512KB/SOC however I can't see the need to drop 7x the amount for line cards that should be able to handle this traffic? We have recently taken the approach of moving the 1G SBCs down to a N5596 VPC stack linked via 20G port-channel (per 5596) from the parent 7ks as I understand the 5596 have different egress queue structures and maybe more suited to handle this type of application?. Any insight would be appreciated. Thanks _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
