I wrote up this blog entry and then deleted the whole entry while editing a typo.   It seems to be a glitch in the developerworks Blog interface, but it could also be a code 16(problem lies 16 inches in front of keyboard).  Anyway....

Cisco have filled a gap in the product line with their new MDS9148.   IBM have offered the 4 Gbps capable MDS9124  24 ports) and MDS9134  (32 ports plus 2 x 10 Gbps ports) for some time.   However for clients who were looking for a future proofed (read 8 Gbps capable) and scalable (read - offers at least 40 ports ala  SAN40B-4)  then clients were pushed up the the MDS9222i.

The MDS9148 ticks all the right boxes.   It starts at 16 ports and scales up to 48 ports by concurrently activating 8 ports at a time.  More importantly there are 8 Gbps of dedicated bandwidth for each port  and 128 buffer credits for every group of 4 ports.  You can allocate up to 125 buffer credits to a single port which is great if you have a distance solution using WDM technology.   Finally the box offers all the usual Cisco functions including hot code activation (which is very important too).

Check out the details here:     http://www-03.ibm.com/systems/storage/san/ctype/9148/index.html

If there is a downside, port densities are getting so high, that swapping out a single switch is becoming far more work.    Having said that, we are now offering 64 port blades for the SAN768B and SAN384B which is great from a port density perspective,  but means even more cables converging into the same real estate.