Editing NetWare (section)

=== Efficiency of NetWare Core Protocol (NCP) ===
Most network protocols in use at the time NetWare was developed didn't trust the network to deliver messages. A typical client file read would work something like this:

# Client sends read request to server
# Server acknowledges request
# Client acknowledges acknowledgement
# Server sends requested data to client
# Client acknowledges data
# Server acknowledges acknowledgement

In contrast, NCP was based on the idea that networks worked perfectly most of the time, so the reply to a request served as the acknowledgement. Here is an example of a client read request using this model:

# Client sends read request to server
# Server sends requested data to client

All requests contained a sequence number, so if the client didn't receive a response within an appropriate amount of time it would re-send the request with the same sequence number. If the server had already processed the request it would resend the cached response, if it had not yet had time to process the request it would only send a "positive acknowledgement". The bottom line to this 'trust the network' approach was a 2/3 reduction in network transactions and the associated latency.