What does a fabric module do in a Nexus switch?

[grapevine]

What does a fabric module do in a Nexus switch?

[Mark Malone]

A fabric module connects the linecards and the supervisors together in a Nexus

So if you had a server connected to a module say in slot 3 using card N7K-F248XP-25 and it was connecting to another card in slot 4 of your 7k switch the fabric module would switch the traffic between these cards in the Nexus

[Jon Marshall]

Just to add to Mark's post -

think of them as providing a path between all the other modules and the supervisor. With the Nexus switches you can add multiple fabric modules and they work together to increase the total throughput of the chassis.

So they allow you to scale your system as your bandwidth needs increase because each fabric module added increases the total amount of throughput of the overall system.

Jon

[grapevine]

Can a Nexus run without a fabric module?

[Jon Marshall]

Depends on the model eg. the Nexus 7004 does not require them but as far as I know the higher models do.

Jon

[Steve Fuller]

A very good presentation on this subject is the CiscoLive BRKARC-3470 - Cisco Nexus 7000/7700 Switch Architecture. The discussion on the fabric modules can be found from slide 41.

The screen shot below shows how the fabric modules are the second stage of a 3-stage switching fabric in the Nexus 7000 and 7700 series platforms.

To John's earlier point, it also shows how each fabric module adds available bandwidth with 110Gbps added per fabric module in the Nexus 7000 switch.

John’s other point, that the Nexus 7004 doesn’t have any fabric modules, is shown on slide 44 as well as how the modules connect.

Regards