Computer Science – 14.2 Circuit switching, packet switching | e-Consult

Call routing is the process by which a switching centre determines the optimal path for a call to reach its destination within a network of interconnected switching centres. The switching centre uses information contained in the dialed number (the destination number) to make this decision.

The routing process typically involves consulting a routing table. This table contains information about the network topology – the connections between switching centres and the associated costs (e.g., delay, congestion). The switching centre examines the destination number and uses the routing table to identify the sequence of switching centres that will lead to the destination.

Factors that might influence the routing decision include:

• Network Congestion: The switching centre may choose a path that avoids congested links.
• Link Capacity: The capacity of the links between switching centres will be considered.
• Delay: The switching centre may choose a path that minimizes the overall delay.
• Cost: In some networks, the cost of using certain links may be factored into the routing decision.
• Network Availability: The switching centre will avoid paths that are currently unavailable due to maintenance or failures.

Sophisticated routing algorithms are used to dynamically adapt to changes in the network topology and to ensure that calls are routed efficiently and reliably.