9618 · 14.2
Circuit switching, packet switching flashcards
Revision flashcards for Cambridge 9618 Circuit switching, packet switching (syllabus 14.2). Flip, recall, then mark a real past-paper question.
Card
What is circuit switching?
A switching method where a dedicated communication path is established between two devices for the duration of the communication session. The path is exclusive and resources are reserved.
Card
What are the three phases of circuit switching?
1. Circuit Establishment: A dedicated path is created. 2. Data Transfer: Data is transmitted along the path. 3. Circuit Disconnect: The connection is terminated and resources are released.
Card
What is a major disadvantage of circuit switching?
It is inefficient. The dedicated channel is reserved for the entire session, even when no data is being sent, leading to wasted bandwidth.
Card
What is packet switching?
A switching method where data is broken into small packets, each sent independently through the network. Packets are reassembled at the destination. This is the basis for the internet.
Card
What is a data packet?
A small unit of data transmitted over a packet-switched network. It consists of a header, payload, and sometimes a trailer.
Card
What information is contained in a packet header?
Control information such as the source and destination IP addresses, packet sequence number, protocol, and time-to-live (TTL).
Card
What is the 'payload' of a packet?
The actual data being transmitted, which is part of the original message.
Card
What is a key advantage of packet switching?
Efficient use of network bandwidth. The communication lines are shared among many users, and data is only sent when needed, maximising resource utilisation.
Card
What is 'jitter' in the context of packet switching?
The variation in the delay of received packets. Since packets can take different routes, they may arrive at different times and out of order, causing uneven playback in real-time applications like video calls.
Card
Why is packet switching considered more robust than circuit switching?
If a particular network path or node fails, packets can be dynamically rerouted around the problem area. In circuit switching, a failure in the dedicated path terminates the entire connection.