[c-nsp] iSCSI SAN, Ethernet flow-control and redundant network topology

[Tim Durack]

I'm coming under some pressure to enable ethernet flow-control and
modify our network topology to keep a Dell iSCSI SAN engineer happy.
(We already have several years successful experience with another
iSCSI SAN, so this isn't new to us.)

>From what I can tell ethernet flow-control probably doesn't work too
well in the age of wire-speed switches. It could be deployed
switch->server if really desired, but even then it might simply
interfere with the higher-layer iSCSI/TCP congestion control
mechanism.

Our DC network topology is straight out of Cisco's DC design guide -
every access switch is redundantly connected to two 6509s, 6509s 2x10G
trunked, 6509s are the STP root. (I'd probably run VSS if it was baked
a little more.)

I've already got some good docs for reference, but any comments from the field?

Tim:>