03-13-2012 05:00 PM - edited 03-01-2019 07:04 AM
Hi,
as per the new EvPC introduced with NX-OS 5.1(3)N1(1) described here (and announced somewhere in the forum by Lucien A.):
It seems, if I well understand, that a solution of this type is now supported:
But questions arises:
1 - what will be the preferred path for est-ovest flow, ie: from server A to server B? link B and then D? or A and then E?
2 - assuming that it will be link B and then link D what will happen to est-ovest flow in this scenario if links B goes down? The new flow will use A / C or A / E / D ?
Any suggestions will be appreciated :-)
Ciao e grazie!
Lucianno
Solved! Go to Solution.
03-13-2012 07:42 PM
Hi Lucianno
Good thoughtful question. Channel hashing is a dynamic function and hence you cannot predict which parent Nexus 5k the FEX would send traffic to or which FEX fabric interface the Nexus 5k would pick.
However, the parent 5k will NOT send the traffic across peer-link(E in your topology) in your set up as long as the vPC to FEX stays up on both Nexus 5k switches.
Hope this helps.
Thanks
-Prashanth
03-13-2012 07:42 PM
Hi Lucianno
Good thoughtful question. Channel hashing is a dynamic function and hence you cannot predict which parent Nexus 5k the FEX would send traffic to or which FEX fabric interface the Nexus 5k would pick.
However, the parent 5k will NOT send the traffic across peer-link(E in your topology) in your set up as long as the vPC to FEX stays up on both Nexus 5k switches.
Hope this helps.
Thanks
-Prashanth
03-15-2012 07:37 AM
Ciao Prashanth,
now it's clear ... basically it's depending on how you set the balance algorithm and you can check this via "show" command (or "test" command, sorry but I don't remember well which one is for 6500 or for NX-OS ).
Thanks a lot!
Ciao Luciano
03-15-2012 07:46 AM
Currently there is not a way to check on the FEX. But on the Nexus 5k, here is an example of me doing it in lab
N5K-B# show port-channel load-balance forwarding-path interface port-channel 996 vlan 620 src-ip 62.1.1.103 dst-ip 62.1.1.105 src-mac 0010.9462.0002 dst-mac 0010.9462.0006
Missing params will be substituted by 0's.
Load-balance Algorithm on switch: source-dest-ip
crc8_hash: 1 Outgoing port id: Ethernet2/16
Param(s) used to calculate load-balance:
dst-ip: 62.1.1.105
src-ip: 62.1.1.103
dst-mac: 0010.9462.0006
src-mac: 0010.9462.0002
N5K-B#
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: