Baystack 450 issue (quite techy)

[DaiSr]

I have a 2 Stacks of 4 450 24p switches numbered 1-4 with the base unit being 1. They are cascaded using MDA modules to produce a redundant cascade. The base unit has a 1000LR fibre port with both a live fibre link to another computer room and a diverse fibre in the failover port.
My problem begins with switch number 3. This also has a 1000LR MDA but at present is not used. I want to run another 2 fibre connections from this to provide redundancy for the base switch. This should allow for a complete failure of the base switch not affecting the network. However I have no idea what impact it will have if I plug another live fibre connection into switch 3, running back to a similarly configured stack in a different room. Can the 2 live fibre ports co-exist in the same stack ?
Thanks for any help offered. I an knock up a quick visio diagram if anyone wants diagramatic look at what im talking about.

 

[JohnJohn]

If you have them in the same spanning tree group one link should span out and be blocked if not you may have a loop. If spanning tree is working and one goes down the other one( the blocked one) will come up after spanning tree recovers. You can also you MLT. Using MLT you get the bandwidth aswell as the redundancy

 

[tkvancouver]

Can you use MLT from two 450's of a baystack to two fiber ports on different boards of a Baystack 8600? i.e. maximize fault tolerance?

 

[vila75]

yes , you can . They call it D-MLT (Distributed MLT ) , it is supported with the 450 switches and the BPS switches but not with the 420 ( only MLT ) , another thing that may help is S-MLT ( Split MLT ) which will be supported in 8600 code 3.2 , using S-MLT , MLT can span boxes rather than only modules.

 

[ecuamer]

vila75
If i have MLT ( two fibers from a closet ) going into two different Gbic cards on a 8610 Passport will that cause a mlt issue .
I am running at this moment 3.1.0.0 image on the passport and 2.0.0.44 on BPS2K and 4.1.0.1 on the 450 's