using C9300-48T/C9300-48P stacked switches as both access and distribution switch at the same time, by utilising the uplink module (C9300-NM-8X, “8x10G Uplink Module

[Tony.V]

What is the downside of using Cisco C9300-48T/C9300-48P stacked switches as both access and distribution switch at the same time, using the uplink module (C9300-NM-8X, “8x10G Uplink Module”)?

We are deploying Cisco C9300-48T/C9300-48P stacked switches across the campus as an access switch. In our current deployed design, each building has few closets (~4 to 5 stacks). Each stacked access switch is port channelled to a pair of stacked distribution switches Cisco “C9500-16X”. and in turn the couple stacked distribution switches are port channelled to our core switch a pair of “cisco C6807-XL”
The utilization on the link between the distribution and the core is very low.
We are using only very few ports on the stacked distribution switches “C9500-16X” in each building (4 out of 14 ports are only used, which is a lot of resource waist)
I’m thinking to make the stacked access switches in the basement as both access and distribution switch at the same time, using the uplink module (C9300-NM-8X, “8x10G Uplink Module). [By doing this we will able to save a lot of money .. over 200K ]
And may be in the future put all the distribution switches C9500-16X in the data centre close to the core.
I would list what I might think a benefit of the new design
But Would please help pointing out downside/drawback of this design? are we sacrificing any performance ? 
Please have a look on the attached pictures
Greatly appreciated

[Leo Laohoo · Accepted solution]

It looks fine for me.

[steeleryan]

My experience is I have to upgrade code regularly on the 9300s because of issues, bugs etc. So If it were me I would not use the 9300s as my distribution. Also I like Stack Wise Virtual with the pair for less upgrade impacts.

The 9300s take a while to boot. Don't have 9500s so not sure about boot time on those. Do you need to reduce equipment or something? I understand about you having more ports than you need. But from an uptime and user availability I would have just kept what you had in place.

With that being said what you proposed should work assuming you have the licensing and feature sets you need.

Are you just looking for a way to move the 9500s into your DC? 

My 2cents

[Tony.V]

Hi steeleryan,

Thank you for getting back to me.

and Sorry may be I wasn't very clear in my original post..

We have just started deploying Cisco stackwise 9300 switches across the campus.

I’m looking for a way to cut down on expenses and save money, by consolidating the access and distribution switches together as long as I'm not sacrificing performance.

Also putting the 9500 distributions in the data centre is not possible at the moment cause we don't have enough fibre between each closet and the DC. 

Cheers

[Reza Sharifi · Accepted solution]

Hi,

You actually don't need distribution switches, as that was an old Cisco, 3 tier design. Theses days most deployments are "collapsed core" which means the core serves as both core and disto as long as the core has enough capacity and ports to handle all the uplinks. So, the suggested-1 design should work but If you have not already purchases the core switches, and have the budget, I recommend looking at the 9600 series for core instead of using a stack.

https://www.cisco.com/c/en/us/products/switches/catalyst-9600-series-switches/index.html

HTH

[steeleryan]

Well according to the most current Cisco VD documents it looks like 3 tiers are still best practice for Campus. I agree that deciding if it's a "need" is important.

https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Campus/campover.html

[Reza Sharifi]

Hi steeleryan,

Of course, Cisco wants to buy more equipment. I just don't see any logical reason for putting traffic behind more devices and causing more delays than what is actually needed. 

HTH

[steeleryan]

Most reputable vendors has VDGs for their products/platforms. Are you saying that their only reason for the guides is to sell more hardware? 

[Reza Sharifi]

That is defiantly one, big reason. I have not deployed distro switches for over 15 years now and don't see the need for it unless you want to deal with extra complexity like dealing with STP, broadcast storms, routing protocols, hardware and software failure, etc..

[tony.viaz]

Hi Steeleryan,
The document that you posted is pretty old. It's 12 years old. May be more than a decade ago it was best practice. But I'm wondering how much it's still valid after all the improvements in the hardware over the last decade and specifically when using stackwise technology...

[steeleryan]

Your kind of missing the point. CVDs are what Cisco says are best based on certain criteria. They have them for most of their portfolio. It really doesn’t matter how old it is if Cisco says it’s still best pratice etc. They do update them as they see the need. Apparently they still think what’s listed is best based on the criteria. See the doc below about CVDs.

https://www.cisco.com/c/dam/en/us/solutions/enterprise/validated-design-program/networking_solutions_products_genericcontent0900aecd80612608.pdf