Page 25 - DCAP406_DCAP_207_Computer Networks

Computer Networks/Networks

Notes
Figure 2.2: Data Flow Control Mechanism

Receiving computer must be capable of distinguishing between information carrying signal
and mere noise.
A mechanism for identifying senders and receivers: Some form of addressing for both
machines and processes to detect whether the information carrying signal is intended for
itself or some other computer on the network, or a broadcast (a message that is intended
for all computers on the network).
Error control: The receiving end after completion of receiving the information must also
be capable of dealing with and recognizing the corruption, if any, this corruption could be
in the form of noise or electromagnetic interference. Both sides must have the same error-
detecting and error-correcting codes. In addition to this, some mechanism is needed to
point out which messages have been correctly received and which have not.

Logical channels: Protocols should provide at least two logical channels per connection.
Message sequencing or ordering: Message are broken into pieces and are numbered before
transmission. There should be a mechanism to put them back in order at the receiving end.
These packets may take different routes to reach at destination computer and therefore not
necessarily be in order.
Routing: The routing approach calls on the implementation of various cooperative
processes, in both routers and servers, whose main concern is to allow for the intelligent
delivery of data to its ultimate destination. Data exchange can take place between any two
workstations, whether or not both belong to same network as shown in Figure 2.3.

Figure 2.3: Router Connecting Two Networks

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