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2407
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5
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VSS Feedback

parisdooz12
Level 1
Level 1

Hi,

we plan to implement VSS on our datacenters (C6509/Sup720), in order to remove L2 loops (currently, access layer are C3750 stacks, which could evoluate for N5K/N2K).

I would like to have some feedbacks about VSS stability. Some years ago, I have seen some bugs with this technology in another company, so I am still not totally comfortable  to use it in the datacenter.

What are your feedback about it?

Thanks by advance.

P.

20 Replies 20

Lee Smitherman
Level 1
Level 1

Installed a VSS 6509 Pair around 18 months - 24 months ago, we did order 4x720 Sup`s but only used a single in each switch as the Dual Sup support had only just been released and we were a little nervous about using it. We kept the others in each chassis as a cold standby.

The 6509 had multiple 40GB(4x10GB) MEC`s to HP C7000 Chassis devices(With Cisco 3120`s) supporting a large Citrix/ESX Environment and to be honest worked very very well. On a couple of occasions we lost a CPU(hardware Issue) in one of the 6509 Chassis`s(Master), however things kept on running and the business didn`t even notice. Swapping out the dead card and bringing the other switch back into prod was also seamless. I loved the single management of the pair of chassis`s as well as the ability to use MEC to other devices, all worked very very well.

When we first setup the 6509`s we patched lots of devices into all of the cards on both switches and ran some extensive tests while we pulled cards, rebooted switches etc and all worked well, with only the occasional ping dropping etc.

Also setting up Dual active detection is advisable incase you loose your VSL links.

I would use it again, given the chance, would also like to hear any experiences with Dual Sup`s in VSS Pairs.

Lee

Many thanks for this feedback.

I would use it again, given the chance, would also like to hear any experiences with Dual Sup`s in VSS Pairs.

Dual Sup in each chassis with SSO in not suported yet.  I am told, it is going to be supported by the end of this year or early 2013. BTW, it was supposed be supported long time ago, but it has not happened yet.

HTH

One question: if we lose a sup card in the chassis: depsite the VSS and even if the VLS link is build between line cards (so not between sup cards), do we totally lose the chassis which lost the sup card, depsite the VSL? (I guess yes ...)

Hi,

this was alien to me at first but yes,  if you loose that sup in the chassis, the WHOLE chassis goes down and all interfaces connected to that chassis(servers etc).  Thats why its very important in a VSS environment to ensure EVERYTHING is dual homed.  With the use of MEC`s etc its not to difficult to achieve.  Key for us was to educate the server guys who can be a little slack at times that everything they plug in must be dual homed if they want their servers to stay communicable during network issues.

Lee.

Edison Ortiz
Hall of Fame
Hall of Fame

VSS is a very mature technology. You shouldn't encounter major problems albeit occasional bugs but that's BAU (Business As Usual).

Regards,

Edison

ok, thanks

aukhadiev
Level 1
Level 1

What can I say... It works... I can not remember any major problems for the (c6500 uptime is 2 years, 2 weeks, 1 day, 11 hours, 20 minutes)

mahmoodmkl
Level 7
Level 7

Hi

just llok into the distance between the chassis as i have seen issues with it if they are far from each other

Sent from Cisco Technical Support iPhone App

Hello mahmoodmkl,

What kind of issues did you encounter with distance between two chassis? I am going to implement the same architecture (two chassis in different sites) and would like to know what kind of issues are waiting for me.

Thanks

smalep
Level 1
Level 1

Hi,

We have been using several VSS's in different locations for several years.  I included two good links.  I would suggest connecting your VSL links so that at least one uses the Supervisor module, but make sure they don't only use your Supervisor.  Spread the VSL links out so one uses the Supervisor and one uses a port on the 8-port 10 gig line card (6708).  The reason is that if you do have a chassis reset the Supervisor comes up first, long before the actually line cards power up.  A typical reboot of a chassis in a VSS, where everything is powered and fully back online takes approx 10 minutes.  The Supervisor is back up in less than 5 min.   

Also, don't forget the ports on a 6704 cannot be used for a VSL link.

The business case for the VSS is that you are able to maintain full redundancy while using all the bandwidth of that redundacy if you dual home to the VSS using an etherchannel from your edge switch.

http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/VSS30dg/VSS-dg_ch4.html

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps9336/prod_qas0900aecd806ed74b.html

Overall we are glad we went with VSS and it has prevented many potentially large and significant outages that if we did not have VSS in place would have caused major impact to our business.

Thanks,

P

We have two datacenters running it now.

It does have its moments as any tech does but on the whole its nice and stable. Just remember to have everything dual homed.

Plus you get to double your uplink speeds by using port-channels now

-Graham
Please note: My comments are simply suggestions. I cannot be held liable for any loss of data, life or marbles due to following my instructions.

Got a website? Need some live chat software?

Hi,

I don't really understand the reason to use the VSL on both supervision card and linecard. In the Cisco documentation I found, the 2 cases were given (case #1: 2 links between the 2 supervisor cards; case #2: 1 link bewteen sup & 1 link between 6708), with no specific advice for one solution specificaly. I don't see what is the impact of the sup card comes up 1st. (in our datacente, we have only 6704 and no need of 6708)

Thanks

P.

Hi,

The issue is that the two 10gig ports on the Supervisor according to the information from CiscoLive 2012,  share a single ASIC,  they suggested that any issue with the ASIC will impact ALL the VSL traffic as opposed to have VSL diversity across multiple cards. Certainly it is only a best practice recommendation from Cisco and not and absolute requirement.

Obviously if you do not have any other line cards that you can use to participate in a VSL then you only option is two use both 10gig ports on the Supervisor module.

Thanks,

P

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