[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

    RE: TCP/IP Framing Assists

    Copying the list on a response to a question of general interest ...
    Charles Monia writes:
    > At the last IPS WG, you said you felt there was a possibility that the
    > community might be persuaded to accept some sort of framing assists for
    > TCP/IP (At the time, I characterized this as 'SCTP lite').
    > Has there been any progress on this front? This could impact the outcome
    > the common encapsulation effort.
    It is still a definite possibility.  There has been progress, but it's not
    visible, yet.  As indicated in the IPS Agenda for Minneapolis, work on this
    will be conducted through the tsvwg Working Group - I have not seen a
    Minneapolis Agenda for tsvwg, so I don't know if/when this issue will be
    taken up.  I'll try to get an update (no discussion) on this topic included
    in the initial 10 minutes of Agenda Bashing and Administrivia.
    For the FCIP/iFCP common encapsulation, I would recommend separating
    framing from data representation, and adopting an approach along the lines
    that in Section 1.2.8 of the iSCSI draft in which framing logically occurs
    between the block storage protocol and TCP.  In particular, this means
    that the 0xfcfcfcfc reserved value/word-stuffing approach in Section 2 of
    the weber draft should be specified separately as a "shim" protocol 
    at this level if it is to be carried forward - this is the right way to
    about it in any case because any protocol headers at higher layers in
    the stack have to be word-stuffed if the reserved value sequence (4
    occurrences of the reserved value in the weber draft) occurs there.
    The result could be three TCP framing approaches
    	- SCTP-lite
    	- Markers (iSCSI appendix)
    	- Reserved value/word stuffing (weber draft)
    Each could be independently chosen/used by any of the IPS block storage
    protocols, provided that suitable negotiation mechanisms are specified to
    make sure that both sides of a connection understand exactly what is being
    used in which direction.
    David L. Black, Senior Technologist
    EMC Corporation, 42 South St., Hopkinton, MA  01748
    +1 (508) 435-1000 x75140     FAX: +1 (508) 497-8500       Mobile: +1 (978) 394-7754


Last updated: Tue Sep 04 01:05:22 2001
6315 messages in chronological order