Connecting multiple stacks to an ISR 4321

[nochannel2013]

Hello everyone,

We're migrating several sites in the enterprise and will move to stacking 9300 series switches together (from stand-alone 2960s et al) and replacing 2800 series routers to ISR 4321s.

The question is, how do I connect two or three stacks of switches to these routers?  I am used to large boxes with multiple line cards (fiber, copper, etc) but I dont have that flexibility this time around.

Suggestions are always welcomed.
Thanks!

EDIT: there is a combination of single mode fiber and copper, for example, one location has three IDFs all connected with SM fiber.  Another location has two IDFs, all switches in each closet will be stacked together but there is no fiber, so they'll have to connect via copper.

[balaji.bandi]

Cat 9300 have uplink modules which support for your SFP.

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/hardware/install/b_c9300_hig/b_c9300_hig_chapter_011.html

based switch have any way Cat 5/6 support with RJ45

is this something what you looking ?

[Giuseppe Larosa]

Hello nochannel2013,

for building a stack it is better to use the appropriate stack cables

see

StackWise-480: The Cisco Catalyst 9300 Series supports the industry’s highest back-panel stacking bandwidth solution (480 Gbps) with StackWise-480. Up to 8 Switches can be configured in a Stackwise-480 with the special connector at the back of the switch using dedicated stack cables.

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-9300-series-switches/data_sheet-c78-738977.html

I don't know if using copper ports is allowed to build the stack, but they would become a bottleneck for performance as 480 Gbps of the stack cables is much more then 8 X 1 GE using a bundle.

Connecting to the ISR 4321 is a different matter and you can use copper (up to 100 meters far) or fiber also depending on what you have installed on the ISR 4321.

Edit:

First of all you can build redundant links between stacks using multi chassi etherchannel.

If you have two stacks one link of  first stack will go the ISR 4321 and one line of second stack will go to another port of the ISR 4321 (if it is only  one router otherwise to second ISR router)

if you have three stacks you first interconnect the three of them with multichassis etherchannel and then connect first stack and third stack to router(s) interfaces.

Hope to help

Giuseppe

[nochannel2013]

Thanks all for the replies.

I guess I didnt explain myself.  I know that I have to stack the switches together using stackwise, and will do so.  My question is, how do I connect three switch stacks via multimode fiber to the ISR4321 when I only have two ethernet ports on the back  (one is copper the other is sfp).

Giuseppe,

when you say "if you have three stacks you first interconnect the three of them with multichassis etherchannel and then connect first stack and third stack to router(s) interfaces." do you mean to connect stack 2 to stack one then stack one and three to the router?

[Giuseppe Larosa]

Hello nochannel2013,

no problems.

I have preferred to provide information about the stack cable.

The idea with three stacks is to have

stack1 ====== stack2 ======= stack3

here with === I mean multichassis etherchannel like stack1 member 1 provides 1 link and connects to stack2 member1, stack1 member 2 provides second link to stack 2 member 2.

The same between stack2 and stack3.

Finally stack1 connects to ISR4321 with one link and stack3 to ISR 4321 second link (or other router)

Hope to help

Giuseppe