Subject: [Ips] DA+iSER Flow Control, Limiting number of oustanding cmds at target

From: "Alex Nezhinsky" <[email-masked]>
Date: Wed, 22 Sep 2004 14:01:56 +0200

Follwing the discussion about Flow Control.

Number of SCSI tasks allowed to be outstanding at target is controlled
by the MaxCmdSN field sent by the target. Although the instant values of
this parameter change from time to time, and initiator learns them
dynamically, it'd be useful if it knew its upper bound. This will avoid
allocation and posting of unnecessary receive buffers.

There is no such negotiation parameter in iSCSI, but it may be added
(for example "MaxOutstandingCommands") to those supported by iSER, as
Declarative, Target-only.

Alexander Nezhinsky
Infiniband Storage Solutions, Voltaire Ltd.

_______________________________________________
Ips mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ips

---

From: Mike Ko <[email-masked]>
Date: Wed, 22 Sep 2004 09:30:44 -0700

The target uses MaxCmdSN to indicate the maximum CmdSN the initiator can 
send.  In other words, it allows the target to determine the number of 
pre-posted buffers required to receive those commands.  However, it is up 
to the initiator to determine how many commands, up to MaxCmdSN - ExpCmdSN 
+ 1, that it wants to send, which in turn determines the number of 
pre-posted buffers needed at the initiator to receive the responses to 
those commands that are sent (SCSI Response, Reject, etc.).  This has 
worked well for iSCSI and I don't see any reason why a new key needs to be 
added for iSER.

Mike
Sent by:        [email-masked]
To:     <[email-masked]>
cc:      
Subject:        [Ips] DA+iSER Flow Control,     Limiting number of 
oustanding cmds at target

Alexander Nezhinsky