Reason for Stackwise-Virtual instead of VSS for Catalyst 9K

[Daniel Lucas]

Anyone know why it was decided to use Stackwise-Virtual instead of VSS in the catalyst 9K series? Seems like a step backwards since stackwise-virtual doesn't support quad-supervisor design.

-Thanks

[balaji.bandi]

Both basically both VSS  and Stackwise virtual provide the same features, so you can't say one is better than the other.

VSS is for Catalyst 4500/6500/6800 platforms, while StackWise Virtual is for platforms like the Catalyst 3850 / Cat 9500. The two technologies are aimed to have feature parity. They both provide SSO with non-stop forwarding and allows two chassis to operate as one single entity. There's no support for more than two switches in either technology.

yes that is the limitation of Stackwise virtual, if you looking more Supervisor you need to consider Modular.

May be soon (hearing all over, cisco coming with Catalyst 9K models - not i was reffering 9400 here)

[Mark Malone]

Hi

Personally i thought quad sup design in VSS was a bit overkill and waste of money , sups rarely in fairness rarely go anyway and in a VSS design chances of 2 going same time very slim , a need for 4 i haven't seen it and we have everything completely redundant from user access to wan edge but that doesn't mean it doesn't exist

why there using it instead of VSS i dont know but the features are basically the same as per previous post , just as Balaji said not all 94s and 95s support stackwise , the 9410 doesn't and either does C9500-24Y4C so far but seemingly on the road map

[Daniel Lucas]

Ok thanks,
Just seems odd to choose not to add VSS to this platform, but instead go with another technology with more limitations.

[Mark Malone]

Why do you think theres a limitation or maybe you have seen something i have not yet ?
this is not the same as switch stacking at user or distribution layer like a set of 6 3650s , ive read most of the docs that i could but i haven't found any real limitations to the stackwise to VSS , it operates same physical logical structure as VSS and even gets set up the same , as far a i can see the names just changed but maybe there is as its new and i dont know everything about it , one issue i have is Cisco leaving certain models out of the stackwise and i see a few people have been caught out because docs says 9ks in general support stackwise but if you dont read the fine print some are not

This an easy to understand link compared to some of the papers out there , explaining setup and to me its near identical to VSS setup but maybe im missing something , even in old quad design in VSS i thought even the sup 3 and 4 of the set would always be in rommon mode anyway and were not all active at same time

https://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-9000/nb-06-cat-9k-stack-wp-cte-en.pdf

[Daniel Lucas]

Quad-Sup being one limitation, and also Virtual-Stackwise is not supported with SD-Access/DNA (VSS is however, or atleast I can't find anything saying otherwise).
I just don't understand why they are re-inventing the wheel - VSS worked well; why not port that over to the smaller access switches instead of creating something new for access switches, and then porting that over to the modular ones. Even the name doesn't really make sense anymore - with 3850s typically you would physically stack them ontop of each other - you're not going to typically stack 9400s or probably even 9500s.
I understand functionality-wise it is the same as VSS; it's just more annoying then anything else i guess.

[Luis Rodolfo Campos Garcia]

Now in 16.9.3 stackwise virtual is supported on 950024Y4C, but still no DNA-C...
Also you cannot use port-channel for the VSL (at least in my experience) nor dual active detection... Thumbs down for cisco at the moment...