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Friday, September 9, 2011

Nexus 1000v, port-channel breakdown?


We are currently configuring a Nexus 1000v. If we have 4 servers, each with a system-uplink NIC, is there a need to dump them each into a port-channel?
Also, should they be trunk ports if all three of our nexus VLANS are using the same vlan?

If we have our 4 hosts, each with 2 NICs...since it's a distributed switch, in theorey, we could disable 7 of the NICs, and the traffic from all 4 hosts would still use the backplane NICs and use that last nic for egress. Is this correct?

Each ESX host will have a VEM module. The VEM module will have one or more uplinks. Each uplink will have one or more physical nics. If an uplink has more than one nic (recommended for redundancy), a portchannel for that uplink is required. If you have more than one uplink, you need to ensure they do not have overlapping VLAN.

In your statement, you stated you have a system and vmware uplink with one link each. You would not port-channel these uplinks together. You may wish to collapse the system and vm uplinks into a single uplink and create a port channel for the single uplink.

The recommended means of creating the portchannel is using LACP where supported. If not supported, MAC PINNING is the recommend means of creating the port channel.

If you have 4 hosts with 2 nics each, you will want to use all eight nics. Each ESX host will need to have access to the network. Either with two uplinks with a single nic each or a single uplink with two nics each.

Please click here for Cisco documentation "Cisco Nexus 1000V Series Switches Deployment Guide Version 2"

Please click here for Best Practices in Deploying Cisco Nexus 1000V Series Switches on Cisco UCS B and C Series Cisco UCS Manager Servers.

Because VM traffic and vCenter activities (ie vMotion) can be bandwidth intensive, it is preferred to have a dedicated port channel for VSM-VEM traffic to eliminate any contention for network bandwidth. With your limitation on NICs, it may want to collapse to single uplink.

You are ontrack with your uplink configuration. If you are using LACP on 4.2(1)SV1(4) or newer, you will want to review 'feature lacp' and 'lacp offload'

Please click here for "Cisco Nexus 1000V Command Reference, Release 4.2(1)SV1(4)"


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