Telephone call routing

Network routing for phone calls works through a series of steps:

• The call originates from a phone, which sends a signaling request to the local telephone exchange.

• The local exchange routes the call to a signaling gateway, which translates the call setup information into a format compatible with the broader telephone network.

• Signaling protocols, such as SS7 (Signaling System 7) or SIP (Session Initiation Protocol), are used to exchange information about the call, including the destination number.

• Network routers and switches use routing tables and routing algorithms to determine the optimal path for the call through the network. This path may involve multiple exchanges, long-distance carriers, and possibly international gateways.

• The call is transmitted over the selected path, typically using circuit-switched technology for traditional phone calls or packet-switched technology for VoIP calls.

• Once the call reaches the destination exchange, it is connected to the recipient's phone.