Circuit switching
(The switch is regarded as a switch with multiple switches) After
data transmission, the connection to
PSTN must be released. It is a typical circuit-switched network. The
circuit-switched bit stream is at the physical layer.
Advantages:
Small communication delay, orderly transmission, no conflict, and wide application range , Strong real-time performance, simple control,
shortcomings ,
long connection time, low efficiency of line exclusive use, poor flexibility, and difficult to standardize
virtual circuit switching
Message exchange
Message exchange transmits frames at the link layer through the switch.
Advantages
No need to establish connections, dynamically allocate lines, improve line reliability, increase line utilization, and provide multi-target services.
Disadvantages
cause forwarding delays, require larger storage buffer space, and require Transmit additional amount of information
Packet switching
Bridge: packet forwarding equipment using packet switching technology. Packet
switching transmits data packets through routers at the network layer. There are two packet switching methods: data packets and virtual circuits. The transport layer protocols TCP and UDP are used. The transport layer TCP protocol is combined with the IP protocol virtual Circuit completion is reliable, while UDP is unreliable for packet switching of data packets.
Switch: Router
Advantages :
No need to establish a connection, high line utilization, simplified storage management, accelerated transmission, reduced error probability and retransmission of data.
Disadvantages
caused forwarding delay, need to transmit additional information, and there are problems of out-of-sequence loss of duplicate packets