stack 9500

[abtt-39]

Hello,

We want to replace our core network, which is currently composed of 4 3850 switches (2 fibers and 2 coppers). These switches are stacked ( physical stackwise cable)

I was looking to go on 9300 models, but one of my suppliers offers me 9500 models with good prices, I don't know this model

But I see the stack technology is not the same anymore, StackWise Virtual

And I also see that this technology limits a stack to 2 switches?
What is the maximum possible bandwidth? 40 Gb?

With a 48-port switch x2 = 96 ports. what if we need more ports? If we are limited to a stack of 2 switches?

I am also looking to create a backed up network core, in a second building, close to the first.
The 2 buildings are connected with fiber.

I don't know this stack technology and I'm looking for documentation, the differences with the old method

I read a number of documentation on google, but I still did not understand exactly how it works ( Multi-Chassis Ether-channel, Dual Active Detection Link
SVL, DAD...??)

Thanks.

[Joseph W. Doherty]

I'm not current on all of Cisco's latest technology, and lingo, but from what you've described, and my briefly skimming StackWise Virtual Whitepaper, it seems to me to be a renamed (possibly enhanced) variant of VSS (Virtual Switching System).  If so, unlike "traditional" StackWise, where traffic is expected to be passed around on the stack ring (like on your 3850s), VSS (and this StackWise Virtual?), the inter switch link is not expected to handle much if any data traffic, as all devices using this architecture are (ideally) expected to have a physical connection to both switches.

Although the goal of this architecture is to avoid data exchange between the switches, the maximum available bandwidth, I believe, is limited by the maximum number of links that can be combined into an Etherchannel, and the bandwidth (must be the same) of all those links.  (For example if switch supported eight 400 Gbps links, you might have something like 3.2 Tbps.)

Actually this architecture is often great for a core, that's just a core.  The most likely issues you might encounter, is whether you'll have sufficient ports and can connect all your downstream device to each switch (dual link Etherchannel often used).

[balaji.bandi]

My suggestion if you moving from Cat 3850 x 4 switches, best to go Cat 9300 - because you can stack upto 8 switches(new techology says 16 - but i never go beyond 4, becuase of management)

with new technology VSS - replaced with enhancement called Stackwise virtual - which supports only 2 switch per domain, you can have more domains (but limited 2 only)  - So you going to use more port to connect SVL and DAD)

if you looking  more ports, Cisco Suggest Cat 9400 chasis (which is expensive than Cat 9300)

So for return of investment i still stick with Cat 9300 and not to tempt to go higher level. (if this is Access switch)

I am also looking to create a backed up network core, in a second building, close to the first.
The 2 buildings are connected with fiber.

in this case you can build 2 x 9500 SVL in both buildings to act as core.

May be woth Looking what options pros and cons of design.

[Joseph W. Doherty]

Just a few notes to add to @balaji.bandi suggesting you might want to still move to 9300s (which likely would be fine for your usage), the 9300s (which might be unclear) and the 3850s (NB: requires specific models, "right" IOS, yada, yada) both support StackWise Virtual.

Something I was just trying to determine, is whether StackWise Virtual would also support its two "switches", if one for both of those "switches" were also traditional StackWise stacks, i.e. with multiple members.  I don't believe you can, yet, anyway.  (Cisco appears to also say wonderful things are yet to come with StackWise Virtual [on 9Ks?].)

[abtt-39]

Thank you for your answers.

In my current network architecture, I don't really have a distribution layer, just a switch core (which also manages ACLs, VLANs, etc.) and access switches to which computers and telephones are connected. , wifi hotspots etc.

yes, in my research, I had planned to take 9300. It's just that one of the suppliers offers 9500 at good prices (but not 9300). And our manager asks us to work primarily with this supplier (a central purchasing office).

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[Joseph W. Doherty]

Well, depending on requirement (performance capacity), a 9500 is "better" than a 9300.  Both appear to support StackWise Virtual, using a physical pair.  The 9300, I believe, also supports StackWise stacks like your 3850.

From what you've described, it seems like, ideally, you would like to be able to stack more than a physical pair, yet also be able to do so beyond typical stacking cable length limitations.  I don't know if Cisco offers this capability on any of their stackable switches, or plan to, but might add I've worked with another vendor's stackable switches that supported stacking more than a pair of switch that weren't physically near each other.  I.e. if Cisco doesn't offer this capability now, possibly it's on a road map.

[rasmus.elmholt]

Take a look at the new 9300X as they are able to stack like you know it. Where as the 9500 in a StackWise Virtual setup is not capable of handling the same bandwidth over the stack, and you are limited to 2 switches in the stack.