Having a Switch that has some optimizations built in for iSCSI, most definitely helps with network performance. This document is a good read and recommends using the 55xx,62xx,70xx,80xx switches. i.dell.com/.../equallogic-iscsi-optimization-powerconnect-switches.pdf Did you have a specific switch in mind?
Hi, I have a basic question about ISCSI SAN? Do you need a special switch, with high buffer rate or something between ISCSI SAN like MD3200i and storage provided to servers? what is the benefit of it over traditional layer 2 switches?  In case when you just have 1 ESX server and MDI3200 SAN, would it make more sense to make direct connection without use of switch or would it cause some issues, latency.  Thanks in advance   
Do I need a special switch for ISCSI SAN?