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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: iSCSI/iWARP drafts and flow controlSince the Asynchronous Message is associated with a StatSN, instead of waiting for the initiator to send "a command with CmdSN that was only enabled after the non-responding target message", another possibility is to wait for the initiator to send any PDU containing the ExtStatSN field that acknowledges that the particular StatSN has been received. Mike Ko IBM Almaden Research mako@almaden.ibm.com To: Mike Ko <mako@almaden.ibm.com> cc: <ips@ece.cmu.edu>, <rddp@ietf.org> Subject: Re: iSCSI/iWARP drafts and flow control On Thursday, August 7, 2003, at 12:52 PM, Mike Ko wrote: > Caitlin, since MaxCmdSN is used by the target to limit the number of > commands it can receive from the initiator, your suggestion would work > for > limiting the number of "fringe" messages the initiator can send to the > target. However, for "fringe" messages from the target to the > initiator, > such as the Aysnchronous Message, the target cannot simply raise > MaxCmdSN > and expect the initiator to increase the number of receive buffers for > "fringe" messages correspondingly. The target may always send untagged messages when they are a response to an initiator request. Additionally the target may have N extra outstanding untagged messages, where N is a protocol constant or negotiated for the session. A non-responding target message is "outstanding" until one of the following occurs: The initiator responds to a "Nop Out Request". The initiator sends a command with CmdSN that was only enabled after the non-responding target message. The fact that a prior non-responding target untagged message is no longer "outstanding" merely means that whatever buffers are allocated for this purpose have been replaced. It does not guarantee that the initiator has completed any associated processing, that logic is left totally to the ULP.
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