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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iscsi : Fragmentation & Reassembly issues in iSCSI.It is better to leave a seperate, possibly lower limit for PingMaxReplyLength -----Original Message----- From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of Santosh Rao Sent: Friday, January 19, 2001 2:00 PM To: julian_satran@il.ibm.com; ips@ece.cmu.edu Subject: Re: iscsi : Fragmentation & Reassembly issues in iSCSI. julian_satran@il.ibm.com wrote: > <js> I will introduce in 04 a statement saying that that PingMaxRelayLength > will be limited by the lowest of the two </js> Julian, The fragmentation issue as explained in the above example is also applicable for the Login and Text Commands. (TotalText > DataPDULength). In the case of these commands, a "F" bit is required in bit 7 of byte 1 of the command & response PDUs to indicate the last command or response PDU due to the fragmentation issues that arise from TotalText & DataPDULength. > Solution : > ======= > Specify explicitly in Appendix C that DataPDULength is only applicable > for SCSI Command PDU and SCSI Data PDU. The current definition is open > to being mis-interpreted as a form of iSCSI MTU, something that can > result in the iSCSI layer having to deal with fragmentation and > re-assembly issues for non-SCSI PDUs. > > <js> What would be those? Text commands? Login? Nops? Having a single limit > seemms simpler </js> On the lines of your above solution, (based on a single limit), removal of PingMaxReplyLength should be considered and implicitly use DataPDULength as the PingMaxReplyLength. This ensures only 1 limit for NOP-OUT/NOP-IN. Regards, Santosh _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com
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