Cisco Fabric Services (CFS) in Nexus

Unanswered Question
Jun 13th, 2012


I am unable to find any documentation how exactly this protocol works in the background. When one must use CSFoE and when to use CFSoIP? When to use multicast address and if multicast routing must be enabled in the network for CFS to work. The config guide show only how to configure, but I need to understand how exactly it works in the background.

Any help is appreciated.


Mohan Muthu

I have this problem too.
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Oleksandr Nesterov Thu, 06/14/2012 - 05:33

Hello Mohan

Here you can find more detailed description how CFS works:

Also few statements regarding the two protocols:

1.)CFSoE packets are always and only transported of the vPC peerlink

2.)CFSoIP mandatory to use the Config-synch feature

3.)CFSoIP packets are always and only exchanged over the mgmt0 interface

4.)CFSoIP and CFSoE can coexist (for n5k)



muthumohan Sat, 06/16/2012 - 06:43

Hi Oleksandr,

Thank you for the links. Appreciate it. I have already seen the links you sent.

What I need to know about CFS is how it really works?

What is the purpose of the IP multicast address for CFS?

How do all the CFS enabled devices discover each other. Do they form neighbor adjaency with each other? How?

How exactly the inforamtion is distributed? Via multicast or unicast? Or is it hop-by-hop or flooded?

When to use CFSoE and when to use CFSoIP?

Why is there a keepalive to detect a topology change? Why CFS need to detect topology change, when its purpose is to just distribute the configuration commmds?

CFS uses only management interface to distribute information. right?

None of these is available in the Cisco documentation.

Any help to understand how CFS works "under the hood" is much appreciated.

Thanks in advance.


Anthony Jentsch Tue, 05/07/2013 - 06:54


Have you found any better documentation on CFS yet? Im in  the same boat. I need to understand how it works before I blindly configure it.




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