Connection-Oriented Transport 685

Connection-Oriented Transport
One thing we could do is ask for a receipt to be signed at the far end so that we know it got
through. This would make our system more reliable, but obviously the service would not be
free, because there is greater overhead and therefore greater cost. In IP networks, we use TCP
(Transport Control Protocol) to handle that receipting process for us, and we call those receipts
acknowledgments. And it isn’t free, because we have to wait for a packet to be acknowledged
before we can send the next one, and that slows down the data throughput.
So in order to work properly, both the sequence number and the acknowledgment numbers
must be synchronized at the start of the data transfer. In fact, other additional parameters also
need to be set at this time, and so TCP has a complex process to initiate the data transfer, called
the
connection sequence
.
In a way, this puts us on the road to QoS-based networks, because we have at least guaranteed
that our data will be delivered. Now we have to deal with all of the other issues surrounding
how it will be delivered.