Potential data corruption in DDP with MSN protocol violation

Based on the current wording in ddp draft 02, clause 9 it appears that a
receiver can place and deliver a sequence of DDP messages that arrive
with sequence number MSN=1, MSN=3, MSN=4 if there is no gap in the LLP
stream sequence. This could only be generated by a protocol error on the
transmitting side. 
However, if the transmitter did indeed generate this sequence
incorrectly it is conceivable that the receiver would have old data in a
buffer associated with MSN=2 and deliver it to the ULP.

Although one does not in general like to have the receiver check for
protocol errors, this may be an area in which the wording of the
standard should be strengthened a bit, such that DDP messages can not be
delivered when there are holes in the MSN space.

Barry Reinhold
Lamprey Networks
[email protected]
(603) 868-8411