ISL restrictions on the 48-port 4-Gbps Fibre Channel Switching Modules

Answered Question
Nov 13th, 2007
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Hi Experts,


i known that there was a restriction for ISL's for the 32-port 2-Gbps Fibre Channel Switching Modules that only one of the four ports per ASIC could be used for ISL.


Is that also valid for the 48-port 4-Gbps Fibre Channel Switching Modules ?


Thanks for your help.


Carsten


Correct Answer by stephen2615 about 9 years 6 months ago

The restriction was dropped with the 2nd Gen cards. The 32 port cards would automatically turn off the other ports so you had no choice in the matter. The only problem now is the over subscription for the port groups. Now you have 12 ports in a port group. If you are going to run your ISL's hot try not to put too many in your individual port groups. In theory each port in the port group running maximum throughput will only have 1 Gbps performance but that is highly unlikely especially in a Windows environment. However, watch large VMWare systems as they can/most probably will gobble up bandwidth way past 1 Gbps. Some use 2 or 4 Gbps with ease. Also watch out for the new HP C Class enclosure Virtual Connect solution. 16 blades in, 4 out. Assuming you have 2 fabrics, thats 2 x 4 Gbps to each switch. It will chew up bandwidth.



Stephen

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Correct Answer
stephen2615 Tue, 11/13/2007 - 23:25
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The restriction was dropped with the 2nd Gen cards. The 32 port cards would automatically turn off the other ports so you had no choice in the matter. The only problem now is the over subscription for the port groups. Now you have 12 ports in a port group. If you are going to run your ISL's hot try not to put too many in your individual port groups. In theory each port in the port group running maximum throughput will only have 1 Gbps performance but that is highly unlikely especially in a Windows environment. However, watch large VMWare systems as they can/most probably will gobble up bandwidth way past 1 Gbps. Some use 2 or 4 Gbps with ease. Also watch out for the new HP C Class enclosure Virtual Connect solution. 16 blades in, 4 out. Assuming you have 2 fabrics, thats 2 x 4 Gbps to each switch. It will chew up bandwidth.



Stephen

williamwbishop Fri, 12/21/2007 - 06:01
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Definately the above poster is correct in that it will not disable ports, but the damned thing is finicky has hell when you get too many ISL's in it.

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