08-13-2014 02:40 AM - edited 03-07-2019 08:22 PM
Hi there,
Is it a problem to give 2 single homed fabric extenders to the same Vpc domain the same fex & Portchannel numbers? (see the attached diagram)
The problem i'm having is when i move host ports from an old 6513 to the new fex'es it can take a very long time (5+ minutes) before i get connection to the server again
Just wondering if this could be the issue!
regards,
Pim
Solved! Go to Solution.
08-13-2014 06:31 AM
It's confusing, but it's allowed. As long as the FEX are port channeled locally only and not configured with VPC. You can dual attach a device to both FEX and configure those ports for VPC. Meaning, you can configure this:
interface port-channel 100
switchport mode fex-fabric
channel-group 100 mode active
But you can NOT configure this (this requires the fex be dual attached):
interface port-channel 100
switchport mode fex-fabric
channel-group 100
vpc 100
You can then connect a device (ie. server) to both FEX and configure this:
interface eth100/0/1
switchport mode access
switch access vlan 100
channel-group 1001
interface port-channel 1001
vpc 1001
The good thing about numbering both FEX with the same ID is that the N5K config will be identical if you dual attach a server via VPC. But, it could be confusing that FEX 100 is actually two different devices.
08-13-2014 06:31 AM
It's confusing, but it's allowed. As long as the FEX are port channeled locally only and not configured with VPC. You can dual attach a device to both FEX and configure those ports for VPC. Meaning, you can configure this:
interface port-channel 100
switchport mode fex-fabric
channel-group 100 mode active
But you can NOT configure this (this requires the fex be dual attached):
interface port-channel 100
switchport mode fex-fabric
channel-group 100
vpc 100
You can then connect a device (ie. server) to both FEX and configure this:
interface eth100/0/1
switchport mode access
switch access vlan 100
channel-group 1001
interface port-channel 1001
vpc 1001
The good thing about numbering both FEX with the same ID is that the N5K config will be identical if you dual attach a server via VPC. But, it could be confusing that FEX 100 is actually two different devices.
08-13-2014 06:31 AM
Thanks danrya,
Do you maybe have any insight on the problem i'm Having:
The problem i'm having is when i move host ports from an old 6513 to the new fex'es it can take a very long time (5+ minutes) before i get connection to the server again
I start Ping -T to the server I re-patch the cable to the Fex
Then it takes for ever before i get my ping back which should not be the case
regards,
Pim
08-13-2014 06:41 AM
If the server port on the 6513 is set as portfast (edge port), the MAC address table (CAM) of the upstream switch will not get flushed so your ping would continue going to the old 6500. You could try doing a ping from the server side to refresh the MAC table quicker.
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