Clarification on continuously incrementing sequence count
kev at bri.hp.com
Thu Sep 25 04:58:49 PDT 2008
* From the T10 Reflector (t10 at t10.org), posted by:
* "Kevin Jones" <kev at bri.hp.com>
FCP makes no restriction on the use of "Continuously Incrementing
Sequence Count". I cannot figure out from the standards (FCP, FC-FS)
exactly how this would work. Below is a contrived example of a WRITE
command with a sequence level retry:
Here are some questions:
1. FC-FS defines continuously incrementing sequence count to
apply to data_frames. data_frames have R_CTL.ROUTING = 0,3,4.
This means all FCP frames (CMD, DATA, XRDY, RSP) and SRR
are affected ?
2. FC-FS is slightly vague on whether there are one or two
SEQ_CNT's for an exchange. I am making the assumption that
there is one for each direction.
3. FCP allows SEQ_CNT to be zeroed for retransmission, but that's
just a "may" so what happens if a sequence is retransmitted in
a class3 connection and SEQ_CNT is "continued". I assume in
the above scenario, the first frame of the retransmitted
exchange would have SEQ_CNT=10 ?
Fibre Channel Tape Firmware
kevin.jones at hp.com
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