Having come from a director class environment, I have to wonder about b2b credits on something smaller like the 9134. It has 64 available per port group which consists of 4 ports. If I intended to purchase something like the 9134 for purely ISL work with FC and FICON, how can I get around this b2b credit issue? I have had nothing but problems with HDS True Copy in our normal (Brocade) fabrics and I have decided to split the replication onto its own "SAN" with ONS 15540 providing the DWDM links. Brocade provide either R_RDY or VC over ISL's and I am not convinced that VC can handle head of line blocking. R_RDY definitely cant as it is not capable of that function. So if I was to run port channels of say 2 x 4 Gpbs over up to 32 kms, my 64 b2b credits is not going to leave anything for the other two ports per port group.
10 Gpbs ISL's seem to be the way to do this.
Any comments are most welcome.