next up previous
Next: Transmission overhead and optimal Up: Protocol design Previous: Optimising throughput

Reliability and end-to-end flow control

The protocol should provide reliable communication. Since DS link networks are very reliable, we decide to accept the maximum BER of for our purposes. The consequence is that the occurrence of an error in the network will result in unspecified system behaviour. We assume that the DS network does not to lose or corrupt any data, however, we should also avoid data being lost by the message receiver due to overflowing buffers. Therefore, a means of end-to-end flow control is required.

We choose not to implement end-to-end flow control via the DS per-link flow control, holding data reception as soon as the buffers are full, since this blocks the network until the receiver executes a receive operation, and therefore leads to poor network performance and possibly deadlock. We use credit based end-to-end flow control: the receiver allows a sender to start message transmission by sending it a credit.



Marcel Boosten
Wed Mar 11 14:25:07 MET 1998