RE: Status summary on multiple connections

["Y P Cheng" <ycheng@advansys.com>]

> -----Original Message-----
> From: Lyndon Ong [mailto:long@nortelnetworks.com]
> Sent: Monday, October 02, 2000 9:48 AM
> > Both of you forget about the case when multiple PDUs are inflight, say
N,
> > N+1, and N+2, and one of them has CRC error, say N+1.  The receiver
throws
> > away N+1 because the bad CRC.  N+2 is received long before N+1 is
> > retransmitted after a timeout by the sender.  Of course, a
> > sequence number inside the PDU will ensure sequentially.
>
> This confuses me.  Why would the application ever see the N+2
> PDU, wouldn't it be queued by TCP until N+1 is delivered correctly?  It
> shouldn't matter if N+2 was delivered first or if it contains a
> sequence number at the higher layer, the higher layer would not get N+2
> before N+1.TCP would presumably not be aware of the boundaries between
> messages at the higher layer, but deliver what it sees as a stream of
bits.

Sorry, I erred by assuming that each command PDU is delivered by a separate
TCP segment. However, on a network with long delay, I do assume that the TCP
segment N+2 will be delivered before N+1 is acknowledged.  If this
assumption is not true, we will have BIG performance problem on a network
with long latency delay.