Multiple Trunks

There is no logical restriction on the number of trunks you can configure. You could even have a second trunk to the same switch if you wanted.

 

 

Assuming the existing and new switches are connected to each other @L2 and the new trunk will carry the same VLANs as the existing one, you will create a loop and you'll need STP to break it. This doesn't mean you need to run STP on the F5 though.

We've done 2 trunks from same LTM to 2 Dist switches, different vlans on the trunks. Each trunks has leg to different dist switch for redundancy with etherchannel on the Cisco side. No issues here. You didn't mention how you'll assign vlans on the trunks so not sure if the source of your question. All our traffic is L3 or above, so don't have any feedback on L2 forwarding.

Also, what sort of aggregation switches are you using? Some devices allow virtual port-channels (e.g. vPC's on Nexus platform) that let you span a trunk (port-channel in cisco talk) across multiple switches. Then you only need one trunk on the BigIP. And vPC's don't need spanning tree.

 

 

H

the existing trunk is to 65K AGG switch and the new switch is to Nx5K ( with vPC )

 

 

As the LTM is connecting to different switches with 1st trunk carrying all vlans, will it be any issue if the new trunk too were to carry All vlans? I'm assuming no.

That shouldn't be an issue but of course, consider the STP impact (and design) careful (like you always do right?). =]

 

If nothing else you've got BPDUGuard configured I'd hope (assuming you don't run STP on the BIG-IPs).

 

 

What is your routing setup on the LTM?

 

 

For example, we have an LTM that has a single global default route (any any forwarding IP VS) with a single trunk to a 6k switch. With this method, you SHOULD NOT establish another trunk with another NXOS switch. It is of course possible but you will have a lot of problems that have been stated above.

 

 

We do have an LTM that have multiple "transits" (multiple forwarding IP VS) that go to our 6k, our NXOS, and our ASA to follow our PCI compliance rules. This is best maintained if you utilize the vlan access lists on the VS configs.

 

 

Either way, you will need to make sure that routing and STP is properly configured across all devices for fail over. I personally have mac masquerading setup on the LTMs to keep this second example working, in case of a failover, but I have "heard" (rumored) that it is not needed anymore but Im more of a "Ill believe it when I see it" kinda guy!

 

 

HTH

 

-e

Hey Eric, why wouldn't you establish a trunk to another NXOS switch?