VLAN Load Balancing between trunks with 3 switches

[shihlin]

I am following the VLAN load balancing between trunks in Cisco website to setup the load balancing in my environment.

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800ae96a.shtml

However, my environment is consisted of three switches. Catalyst 6509 x 1 and catalyst 3500 x 2.


Cat6509----WiFi (2nd)-------Cat3500a
\ /
Laser (Main) Cat5e
\ /
----------Cat3500b--------

However, due to both main links are running in wireless it seems like priority does not work very well. Even if the links are down, the port still shows up and running. Is there any other way I can load balance or failover the Laser / WiFi if one goes fail. What commands I should program these 3 switches to make load balancing / failover happen when Laser goes down or another way around?


Thanks,


SL

 

[Fluxor]

Because of the design you have.. you may want to consider setting up routing between the 2 3500's and the 6509 .. This way if you use like OSPF when a link goes down you'll lose the OSPF adjacentcy on that link and you'll have proper failover.

A layer 2 alternative may rest in looking closely at your Laser and WiFi gear.

 

[shihlin]

Thank you for your valuable suggestion Fluxor. However, since it is a small network that is connecting to cat3550, we don’t have any plan to install router to handle routing. Is there a way to configure 3 switches with VTP load balancing? I try configure a test lab with 2 switches environment and it works. The AP can pass trunk and vlans over the WiFi. This lab consists of 2 cat2900, 2 Dlink DWL-2100AP (the one that running WiFi), and 2 notebook.

Thanks,


SL

 

[xp]

Do you need to run seperate VLANs? If not, just run RSTP with default VLANs. We run a similar setup and adjust port priorities to give preference to the fibre link. The links don't load balance, but the fibre carries the traffic until it fails, STP cuts over to the WLAN link after about 30 secs.

Brian

 

[shihlin]

Thank your suggestion and reply, Brian. Unfortunately, I need pass 3 Vlans (Vlan1, 5, and 6) through either WiFi or laser. I setup the port cost and port priority on these 3 switches but still failed. When laser goes down the connection to other side of cat3500 also goes down. Do you mind to copy and paste your switch configuration (only the RSTP part) in Tek-tips? So in you case if laser went down, it take 30 second to failover the WiFi links??

Thanks,



SL

 

[xp]

I will get the config in the next couple of days. I will be away from the office until then. The recovery time improved by adjusting the timers. Because the wireless doesn't support RSTP, I was restricted to PVST+. Recovery once fibre is restored is below 2 seconds in testing.

Brian