Proper Way To Connect Two 3400's To Two Cisco 6509's

I'd recommend connecting one LTM to one switch. Although I've deployed both scenarios without issue (with and without Cisco VSS blades), I'm pretty sold on the one-to-one connectivity standard. Main reason being, if core switch 1 dies, then you're left with two LTMs with only 50% available bandwidth. I'd prefer have one LTM with 100% bandwidth availability and focus on a prompt replacement/repair of core switch 1. The trade-off, while only a minor advantage, is that you'd still have redundant LTMs online. I suppose the only situation where I'd support the alternative solution would be if you had older, non-supported core switches that could potentially be in a non-redundant state for an extended period of time (>1 day).

 

 

Anthony

We are debating a 1 LB to 1 6500 scenario, as right now if each LB is connected to each 6500, 1 uplink on each LB will not come up. The cisco shows that interface as down (not connected).

 

 

How do you get the uplinks to become active for both interfaces in the LB to each cisco swicth?

Hi Btray,

 

It should be as normal as setting up any interface on cisco. If you are not getting a UP on the Cisco make sure the LTM's interface is active as well.

 

 

Bhattman

 

That is the crazy part though. If both uplinks go to one cisco both ports come up, they only stop working when one uplink goes to one cisco and the other uplink goes to cisco number 2. if the working cable is plugged into the non-working port on the LB, it works....

 

 

Both LBs have the exact same issue. 2 uplinks to one cisco, both ports come up. 1 link to each cisco, only one port comes up.

 

 

These are LTM 6400's to cisco 6500's. GigE ports, cisco GBICs to copper.

When both uplinks go to one cisco each LACP is enabled.

LCAP on Cisco IOS 6500 on a single switch. You must configure TRUNK on the LTM so that it works correctly.

 

 

Thanks,

 

Bhattman

Hi Bhattman, your insight is definately appreciated.

 

 

LCAP is off and on as we try various testing now. The main issue we're trying to figure out is why both uplinks only come up on one of the LBs when both uplinks are connected to the same Cisco.

 

 

Both LTM's have the exact same issue.

You can't have both sides of the trunk active (switch1 and switch2) from a single F5 unless you are running VSS. It’s just like configuring a port channel between a 3560 and two 6500s, spanning-tree will block one of the ports from the 6500 side. You can't properly aggregate traffic across the links of two different switches.

 

 

One question though. Why are you trying to bundle all eight ports? The 3400s only have a traffic throughput of 1Gbps even though it has eight gigabit ports. Really, all you need is two ports to each F5 for port redundancy if you really want it.