iSCSI Marker questions

[Dean Scoville <Dean.Scoville@qlogic.com>]

The iSCSI Draft 9 Appendix C makes the following statements about 
Markers and the Initial Marker-less Interval:

     "The offset to the next iSCSI PDU header is counted in terms
      of the TCP stream data. Anything counted in the TCP 
      sequence-number is counted for the offset. Specifically this 
      includes any bytes "inserted" in the TCP stream by an UFL and
      it excludes any other markers inserted between the one we are
      examining and the next PDU header."... 

     "To enable the connection setup including the login phase 
      negotiation, marking (if any) is started only at the first 
      marker interval after the end of the login phase."

I understand that markers are not inserted until after login phase. 
Am I correct to assume that the placement of the first marker 
determined by the TCP sequence numbers on the final Login Request/
Response PDUs, or is initial marker position determined by the 
TCP sequence numbers at connection establishment?

Assume the following interaction:

I->  SYN     (TCP sequenceNum=1000)  -- irrelevant to this discussion?

T->  SYN-ACK (TCP sequenceNum=2000)  -- irrelevant to this discussion?

I->  Login Request PDU, T=0,CSG=1,NSG=0:
     InitiatorName=xxx
     TargetName=yyy
     SessionType=normal
     ...
     FMarker=send-receive
     RFMarkInt=512,1024

T->  Login Response PDU, T=0,CSG=1,NSG=0:
     ...
     FMarker=send-receive
     SFMarkInt=1024
     RFMarkInt=1024

I->  Login Request PDU, T=1,CSG=1,NSG=3:
     SFMarkInt=1024
     (64-byte PDU... TCP sequenceNum=1301-1364)

T->  Login Response PDU, T=1,CSG=1,NSG=3:
     (48-byte PDU... TCP sequenceNum=2201-2248) 

The above interaction designates a 1024 x 4 = 4096-byte marker 
interval in both directions. The first PDU byte sent by the 
intitiator in full-feature mode will have sequenceNum=1365, and 
the first byte sent by the target will have sequenceNum=2249.

Assuming the markerless interval starts at the end of login 
phase, the first two markers in each direction will have the 
following TCP sequence numbers:

               TCP SeqNum of    TCP SeqNum of
               First Marker     Second Marker
               ------------     -------------
Initiator:     5461-5468        9565-9572
Target:        6345-6352        10449-10456

Is this the correct interpretation of marker usage in iSCSI 
Draft 9, or does marker placement depend on the connection's
initial sequence numbers?

Also, is "RFMarkInt=..." always considered an offer, and "SFMarkInt="
considered a reply to that offer? If an offer is sent with "FMarker=..."
and "RFMarkInt=...", MUST the reply contain either "FMarker=no" or
BOTH "FMarker=yes" and "SFMarkInt=..."?

Thanks,
Dean Scoville
QLogic Corp.