02-18-2012 08:01 PM
The current config is 2 fabrics. Each fabric contains 2 switches (4900 + 5300) that are ISL trunked to each other.
We're going to add a 3rd switch (5300) to each fabric, but the 3rd switch of each fabric will reside in a different part of the data centre, basically extending the 2 fabrics to the new location.
Would it be a valid ISL config if I connected the 3rd switch of each fabric to 1 or more ports of each of the first 2 switches, which would provide some extra fault tolerance in the event that 1 of the 2 switches in the fabric went away?
Both fabrics would end up looking like this.
02-19-2012 10:01 AM
You should consider if ports on the new switch will have zones to ports on the 4900 or not.
If not use the ISL ports to create a trunk between both 5300s and create a "line".
From a pure topology view the triangle is a good design but if one switch is not using one of the two other swithces you will have one ISL connection without any traffic. This means wasted ports without any benefit.
I hope this hepls,