FCoE

[Rishav Garg]

Hi All,

I have an scenario which is attached in  attachment  Now my question is below acc. to scenario.

My question is why we can't make VFC over VPC. when i did VFC over VPC it's not coming UP. WHy we have to run another link for FCoE traffic like eth 1/5 and 1/6

Why it can't run over VPC link. if it so then how could it be True in case of FCoE storage in same scenario both VPC and VFC on same link eth 1/32 on both nexus switches i.e. also VPC link

Kindly help.

[Walter Dey]

Fibrechannel design requires a dual fabric which is isolated, left / right or A / B. vPC would violate this rule. Therefore it's only used for Ethernet (IP).

[Rishav Garg]

Hi Walter,

I agree with you. But if we want to Create VFC over VPC. Does VFC come up. 

Why VPC wouldn't support this. Any reason?

I believe that its more resilient if one link fail then storage would go from redundant path.

As part of isolation what if i wouldn't care about seperate path?

[richbarb]

Hi Garg,

This traffic isolation design is not a cisco constraint, but a FC fabric network requirement.

Remember FCoE uses the same design as fibre-channel, since FCoE is just fibre-channel encapsulated.

BTW, you can use vfc through vpc links in some circumstances, but the vfc traffic will not use the vpc ethernet redundancy or load-balancing feature.

This article might help to understand:

http://datacenteroverlords.com/2011/09/14/fibre-channel-and-ethernet-the-odd-couple/

Richard

[Rishav Garg]

In Native Fibre channel, If we use SAN port channel it will do load balancing or even in case of VFC if we use dedicated link for FcoE trafffic. 

Then why it wouldn't do load balancing in case of VPC. Any reason?

[richbarb]

Hi Garg,

In the FC world there is a rule: the SAN A and SAN B must be isolated.

If you mix up the FC traffic to two different nodes in the same level, you are breaking this rule. This is not a matter about traffic forward capability but technology implementation, in this case fibre-channel.

Richard

[Rishav Garg]

I agree with you

but if i want to mix means if i make same vsan on both nodes and zoning config also acc to correct PWWN  no of correct port.

will it work in vpc or not? I want to know that only acc to attached scenario. If i remove dedicate fcoe link and run dual traffic over vpc links.will it work in vpc or not?i dont care about isolation.

will it work in vpc or not?

[richbarb]

Gi garg,

I don't understand when you say "acc". You mean one fabric interconnect using vpc upstream with FCoE in both links? this is not supported.

Anyway, this document will guide you what's is supported or not with UCS, VPC and FCoE design.

http://www.cisco.com/c/en/us/support/docs/servers-unified-computing/ucs-manager/116188-configure-fcoe-00.html#anc6

Richard

[Rishav Garg]

Actually you are right about what you said

one fabric interconnect using vpc upstream with FCoE in both links.

that same thing i want to know why this is not supported. 

I think this is more resilient. Like Fcoe traffic travel in any direction as like ethernet.

if i do zoning accordingly.

[Walter Dey]

Sorry, this is a typical rat hole discussion, between networkers and storage (san) Folks.

- FC is NOT Ethernet, although FCoE is transported over lossless ethernet

- you try to do multihop FCoE, which is more challenging than single hop FcoE (only within UCS, or Access)

- FC Routing and pwwn zoning are 2 different concepts.

- the separation of FC fabrics exists since decades and is supported by all major storage vendors, like IBM, HP, Netapp, HDS, Brocade ...

- Separation also guarantees FC Frame in order delivery !