VN-Link with Blade Switches

Answered Question
Nov 3rd, 2008

I have been looking into the Cisco VN-Link technology and it looks pretty good. The only question that I have relates to the traffic from the server to the Nexus 5k. The docs talk of tagging packets so that they can bypass the v1000 and be processed on the 5k. Does anybody know how a 3100 series blade switch would fit into this equation or would it break it?

I have this problem too.
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Correct Answer by bhedlund about 8 years 1 month ago

The VN-Link VNTag implementation is designed to be used with the first physical switch connected to the Hypervisor server.

While the hardware on Nexus 5000 is VNTag ready, the NX-OS software needed to enable the implementation will not be able until the 2nd half of 2009. Around that same time we should also have a Nexus blade switch available that will support the VNTag VN-Link implementation as well.

The Nexus 1000V software implementation will be available sooner with the intial release of VMWare ESX 4.0 - currently targeted for the 1st quarter of 2009.

So, if I were you, I would use the Nexus 1000V on the hypervisor while you have your 3100's. When you upgrade the 3100's to the Nexus blade switch you can consider using the VNTag implementation at that time.

Hope this helps.

Please rate my posts.

Thanks,

Brad

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bhedlund Wed, 11/05/2008 - 19:20

VN-Link is an umbrella marketing term that describes two different ways to get per VM network visibility.

The first method is a software based approach with Nexus 1000v, where the VM connects to a software based switch running on the hypervisor. With N1000v there is no special requirements for the first upstream physical switch, as it is doing nothing different than before.

The second approach under the VN-Link umbrella is a hardware based solution where the hardware of the first upstream physical switch is used to provide the interface for each VM. The hypervisor simply applies a unique tag to the packets of each VM - called a VNTag. This VNTag acts like a patch cable extending from the VM's vnic to the physical switch. The physical switch will have a unique VEth interface for each downstream VM.

The VNTag method will initially only be available in the Nexus 5000 line of switches. So, to answer your question, you will not be able to use the 3100 blade switches for a VNTag implementation. You will however be able to use the Nexus 1000v software method, and having the 3100 blade switch will keep the networking operations consistent from the network core, all the way into the hypervisor.

Hope this clarifies.

Cheers,

Brad

mmacdonald70 Thu, 11/06/2008 - 04:19

Brad,

Thanks for the information. Just for clarity sake, the 3100 would be between the V1000 and the Nexus 5020. Will HW based VN-Link still not be available is the packets have to pass though a 3100 on the way to a 5020?

bhedlund Thu, 11/06/2008 - 15:28

Before I answer, let me ask:

Were you planning on connecting your 3100's to Nexus 5020 regardless of VN-Link, or are you entertaining this thought specifically for VN-Link?

Thanks,

Brad

mmacdonald70 Thu, 11/06/2008 - 17:49

The hardware is already ordered. VN-Link you just a bonus for the future.

Correct Answer
bhedlund Thu, 11/06/2008 - 19:22

The VN-Link VNTag implementation is designed to be used with the first physical switch connected to the Hypervisor server.

While the hardware on Nexus 5000 is VNTag ready, the NX-OS software needed to enable the implementation will not be able until the 2nd half of 2009. Around that same time we should also have a Nexus blade switch available that will support the VNTag VN-Link implementation as well.

The Nexus 1000V software implementation will be available sooner with the intial release of VMWare ESX 4.0 - currently targeted for the 1st quarter of 2009.

So, if I were you, I would use the Nexus 1000V on the hypervisor while you have your 3100's. When you upgrade the 3100's to the Nexus blade switch you can consider using the VNTag implementation at that time.

Hope this helps.

Please rate my posts.

Thanks,

Brad

gnijs Wed, 11/19/2008 - 12:27

Mmm..interesting to learn there will be a Nexus blade switch in the future :-)

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