Brocade MP7500B FC Fastwrite

I've seen the same feature in Cisco 9216i and in theory this will save you 1 1-way trip of an aknowledgement (from the far side to the local side). If you have a huge latency of let's say 6ms or so, this will save you 6 out of 24ms of the whole round trip "stream" of data.
- are you there ?
- yes, I am (this one will be killed / spoofed)
- here's the data
- thank you

It's something similar to that.....

the official EMC explanation is:
Question: What is FCIP Fast Write?
Answer: FCIP Fast Write optimizes performance of synchronous applications in high-latency WANs by reducing the number of round-trip handshake messages required to complete a write I/O. This results in both a reduction in I/O completion latency as well as an increase in FCIP ISL bandwidth utilization over expensive WAN links.

EMC doesn't support FC Fastwrite as of FOS6.0.0b. No SRDF performance gained when it is turned on. Instead it causes RA links to go down during heavy activities. I would recommend disabling it until EMC supports it (can anyone from EMC tell me when it would be formally supported?)