Thanks Moojit. I found some more information. It's not a mailgram but a
mailbox. This is an EMC and in one document, I found the following:
"ELS buffers are needed to support Fibre Channel Extended Link
Services. ELS buffers are also used for SLI-2 FCP buffers (one per FCP
command) and Mailbox commands."
I am trying to understand where Mailbox commands fit in with SCN and
FCP commands. What are Mailbox commands used for?