ASK THE EXPERT - Nexus 5000 & 2000 series

[ciscomoderator]

with Lucien Avramov

Welcome to the Cisco Networking Professionals Ask the Expert conversation. This is an opportunity to learn how to troubleshoot Nexus 5000 & 2000 series with Lucien Avramov.  Lucien is a customer support engineer at the Cisco Technical  Assistance Center. He currently works in the data center switching team supporting customers on the Cisco Nexus 5000 and 2000. He was previously a technical leader within the network management team. Lucien holds a  bachelor's degree in general engineering and a master's degree in  computer science from Ecole des Mines d'Ales. He also holds the  following certifications: CCIE #19945 in Routing and Switching, CCDP,  DCNIS, and VCP #66183.

Remember to use the rating system to let Lucien know if you have received an adequate response.

Lucien might not be able to answer each question due to the volume expected during this event. Remember that you can continue the conversation on the Security discussion forums shortly after the event. This event lasts through March 11, 2011. Visit this forum often to view responses to your questions and the questions of other community members.

[s.leyer]

Hi Lucien,

LACP is supported on FEX with N5K. Recently we have attached 2 2248 to a 7010
(running 5.1.2) and it's not allowed to build an endhost port-channel (no vPC)
on FEX ports. Message: "channel-group not supported for interface type".
feature lacp is enabled.

I cannot find any documentation about this issue.
Is it a bug or really not supported ?

Thanks
Silvia

[Lucien Avramov]

You are correct, this is not yet supported when the FEX is attached to the N7K. However this is just a software limitation at this time on the N7K, and future release of code will provide you this functionality.

In the meantime you can have a vPC and connect this server across two fabric extenders.

[dtran]

Hi Lucien and thanks in advance for your time !!!

I am looking into a N7K and N2K deployment scenario and have a few questions.

1 - I understand as of today you can only run port-channel between an N2K and a single N7K (vPC is not supported). Is this correct ?

2 - Will vPC be supported between N2K and N7K in the near future ? Do you have a timeline when the next NX-OS release will be out that supports vPC between N2K and N7K ?

3 - With the N2K running port-channel to N7K. When you upgrade the software on the N7K, the N2K will automatically pull its new software image from the N7K then reboot correct ? if so, does this happen automatically after the upgrade is complete on the N7K ? is there any way to schedule the N2K to run its upgrade at a later time to mininize production interruption since the N2K upgrade requires a reboot ?

4 - Do you foresee any issues / concerns in this deployment scenario ? I would love to be able to vPC between N2K and N7K.

Thanks again Lucient !!! Looking forward to hear back from you !!! very much appreciate your help !!!

D.

[Lucien Avramov]

Actually there are some good news here: you can run vPC on N7K for FEX starting 5.1 code.

The FEX downloads it's code from the N7K.

The upgrade of the OS of the 7K will push the new code onto the FEX and reload the FEX at the sametime the 7K is reloaded, you can not avoid that as far as I know.  So feel free to upgrade to the 5.1 release on N7K and use vPC on your FEX.

[nnils]

Hi Lucien,

this is not a nice software limitation ... port-channels are very important in a datacenter.

Is the limitation solved in 5.1(3) or 5.2(1) ???

[Lucien Avramov]

From 5.2 you can have port-channel to the same fex or over vPC

[mario-leitao]

Hi

When will the L3 daughter card be available for the nexus 5K and what will be

the partnumber for it?

[Lucien Avramov]

The card is available for ordering! The part number for the daughter card, for 5548 is :N55-D160L3.

If you have a 5596, you can order an extansion module, the part number for the L3 module for the 5596 is: N55-M160L3

[dtran]

Hi Lucien,

That's excellent news !!! I understand a lot of customers have used vPC from N5K to the FEX. But vPC from the N7K to the FEX is new. Have you seen customers use vPC between N7K and FEX ? Do you foresee any issues / concerns with vPC between N7K and FEX ?

Thanks again Lucien !!! very much appreciate your help !!!

D.

[Lucien Avramov]

Sorry, I was maybe a bit confusing, you can do vPC between the FEX and the end host (servers) from 5.1.

vPC between 7k and FEX is not supported. Do you see a need for it? You can have dual supervisor on the N7K, so there goes your high availability.

[dtran]

Yes, I would like to be able to run vPC from the N7K to the FEX.  I am actually on a project working on replacing my core 6509 with a pair of N7K switches and I am looking at the N2K for Top-of-Rack. Please clearify the questions below for me !!! I don't see the need to have the N5K at this time for my environment. Thanks Lucien !!!!!!!

1 - I understand as of today you can only run port-channel between an  N2K and a single N7K (vPC is not supported). Is this correct ?

2 -  Will vPC be supported between N2K and N7K in the near future ? Do you  have a timeline when the next NX-OS release will be out that supports  vPC between N2K and N7K ?

3 - With the N2K running port-channel to  N7K. When you upgrade the software on the N7K, the N2K will  automatically pull its new software image from the N7K then reboot  correct ? if so, does this happen automatically after the upgrade is  complete on the N7K ? is there any way to schedule the N2K to run its  upgrade at a later time to mininize production interruption since the  N2K upgrade requires a reboot ?

4 - Do you foresee any issues / concerns in this deployment scenario ? I would love to be able to vPC between N2K and N7K.

[Lucien Avramov]

1. Yes

2. Not that I am aware of, but I can speak for what is released at this point. Your sales account team, will help you as far as roadmap. Again why would you even need this feature on an N7K? You just need to have 2 supervisors already on that chassis and that will take care of the redundancy.

3. Yes it does, it's automatic, there is no way to postpone this to later time, the upgrade happens along with the N7K. Again to minimize the downtime the FEX reboots as the same time the 8k does.

4. I dont see issues

[dtran]

Thanks Lucien !!!! I see your point in regard to having dual Supervisors in the N7K and that's what I will have (dual Sup's in each N7K) but I like the idea of having the extra layer of redundancy by having the N2K connecting to each N7K via vPC in case one of links fails or one of the N7K's completely dies. Please share your thoughts on this !!!

You've mentioned vPC can be done between FEX and end host (servers). Let's say that I have two N7K's (N7K-1 and N7K-2) connected via vPC and the FEX is connected to N7K-1 via port-channel. Can I vPC to an end-host with one link connects to the FEX and one link connects N7K-2 ?

Also similar question but in a different scenario. In this scenario I also 2 N7K's (N7K-1 and N7K-2) connected via vPC with a FEX connects to each N7K via port-channel, so one FEX connects to N7K-1 and one FEX connects to N7K-2. Can I vPC to an end-host with one link going to each FEX ?

Thank you very much Lucien !!!! You have been very helpful !!! and I very much appreciate your help !!!!!!! please let me know if my questions aren't making sense.

D.

[Lucien Avramov]

You can have multiple line cards on 1 N7K, and connect multiple uplinks between a FEX and 7k. Added the dual supervisors, you have a total redundancy as far as the 7k is concerned. You can also have multiple FEXs and dual home server to 2 FEX in case of a FEX failure. Your FEXs needed to be connected on the same N7K, for a server to be dual homed to 2 FEX.

[tbleise]

Hello Lucien,

I try to find details about the ingress/egress buffer size and QoS characteristics of the Nexus 2248. While there is a nice document about the Qos of Nexus 5000 on

http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9670/ps11215/white_paper_c11-622479.html

I could not find something similar for the Nexus 2000 (in particular 2248).

My questions are

1. what is the ingress and egress buffer size for each port?

2. does the Nexus 2248 implement VOQ between the host ports and the fabric ports?

    If not, what buffering scheme is deployed?

    If yes, how many ingress / egress queues are there? Can the buffer allocation be configured per system class, similar to Nexus 5000?

3. Do all the QoS commands described for the Nexus 5548 (like policy map attachment, buffer allocation per class etc.) only apply to "directly" connected Nexus 5000 ports or does it also apply to Nexus 2000 Ports?

   If yes, are there limitations? May depending on the Nexus 2000 model attached?

   If no, which command is supported and which is not?

Thanks in advance for your help!

Best regards,

   Thorsten