CS601_Topic117

Summary

This video explains the process of communication in a circuit-switched network, highlighting its three main phases: setup, data transfer, and teardown. In the setup phase, resources are reserved through a dedicated circuit between the two communicating systems. After an acknowledgment is sent, the data transfer phase begins, where data is exchanged using the reserved circuit. Finally, the teardown phase releases the dedicated resources after the data transfer is complete. The network ensures a dedicated, uninterrupted connection between the parties throughout the communication process.

Takeaways

• 😀 Circuit-switched networks have three main phases: setup, data transfer, and teardown.
• 😀 The setup phase involves reserving resources and establishing a dedicated circuit between the communicating systems.
• 😀 System A initiates the setup phase by sending a setup request to System M, which includes the address of M.
• 😀 Switches in the network (e.g., Switch 1, Switch 4, Switch 3) find available channels to establish a path for communication.
• 😀 Once the setup request reaches System M, it sends an acknowledgment to System A to confirm the connection.
• 😀 Data transfer only occurs after the setup phase is completed and both systems have acknowledged the connection.
• 😀 During the data transfer phase, the reserved dedicated circuit is used to transmit data between System A and System M.
• 😀 All resources, including channels and switches, remain dedicated to the communication until data transfer is complete.
• 😀 The teardown phase begins only after all data has been successfully transferred between the systems.
• 😀 Once data transfer is complete, the connection is terminated, and the reserved resources are released for other communications.
• 😀 Circuit-switched networks provide a continuous, dedicated communication path, ensuring uninterrupted data transfer.

Q & A

What are the three distinct phases in a circuit-switched network?

The three distinct phases in a circuit-switched network are: the setup phase, the data transfer phase, and the connection teardown phase.

What happens during the setup phase of a circuit-switched network?

During the setup phase, resources are reserved for communication. This involves setting up a dedicated circuit, which is a combination of channels on a link, between the communicating parties.

How is a connection established between two parties in a circuit-switched network?

The connection is established when Party A sends a setup request to Party M. This request is routed through multiple switches, which find available channels to connect Party A and Party M.

What is the role of switches in the setup phase?

Switches play a critical role in the setup phase by finding available channels between themselves and the other switches or end systems. Each switch forwards the setup request until it reaches the destination party.

What happens after Party M receives the setup request?

Once Party M receives the setup request, it sends an acknowledgement back to Party A to confirm that the connection can proceed.

When does the data transfer phase begin in a circuit-switched network?

The data transfer phase begins only after Party A receives the acknowledgement from Party M, confirming that the connection is established and ready for data transmission.

What happens during the data transfer phase?

During the data transfer phase, Party A sends its data to Party M using the dedicated circuit established in the setup phase. The resources remain reserved for this communication until all data is transferred.

What does the teardown phase involve?

The teardown phase involves disconnecting the established circuit and releasing the dedicated resources once all the data has been successfully transferred.

Why are resources reserved during the data transfer phase?

Resources are reserved during the data transfer phase to ensure that the communication between the two parties remains uninterrupted and that no other communication uses the same dedicated channels.

Can the resources be used by other connections during the data transfer phase?

No, the resources remain dedicated to the ongoing connection between Party A and Party M during the data transfer phase and cannot be used by other connections until the teardown phase is completed.