VPC without port-channels ?

[from88]

Hello,

I have two questiongs regarding VPC technology:

1) We have two basic VPC topologies (see the picture)

What is the practical difference between that (green line) topologies ?

http://imgur.com/a/vBv5Q

2) Do it's possible to run VPC using that topolgies without any port-channel to servers - with just two separate ports facing servers ?

Thanks

[Georg Pauwen]

Hello,

the main difference as I understand it it that  in the EVPC setup, all links are active and passing traffic. Are you sure that pictures 2 and 3 don't have the headings reversed ? 2 seems to be the dual homed, while 3 seems to be the single homed...

Either way, as with regard to your second question, the - server in your case - needs to support IEEE 802.3ad PortChannels, so it has to be a port channel...

[from88]

still dont catch the point - what is better and why ?

both models have the same number of interfaces used, and so on.

[Reza Sharifi]

For connecting servers to FEXs, you have multiple choices;

1-Connect the server via 2 links to 2 different FEXs, configure NIC teaming and configure Portchannel/vPV on Cisco switches.

2-Connect the server via 2 links to 2 different FEXs, configure NICs for high availability and no need to configure any Portchannel on Cisco switches (just trunk or access ports). The second scenario is commonly used for VM connectivity using for example Dell or HP servers to Cisco switches but both scenarios work fine.  It is just a matter of preference. 

HTH

[marcopolo07]

I have a similar question on port-channel usage and best practices. In relation to your option 2, I have a server via 2 links connected to two different FEXs. It's a hot-not situation. I just created it with access mode and same vlan on each FEXs. Do I need to create a port channel on the FEXs interfaces even though there are no 2 physical connections per FEXs? Does that also apply to switches on the access layer connecting to FEXs?

[Reza Sharifi]

Hi,

What is the practical difference between that (green line) topologies ?

In one picture, the FEXs are dully attached and in the other one singly attached.  The recommendation is to use the single attached FEXs.

2) Do it's possible to run VPC using that topolgies without any port-channel to servers - with just two separate ports facing servers ?

Yes, you can use vpc or just attached the ports from the servers to the FEXs and let the servers do the load balancing. Either scenario works fine.

HTH