According to the transmission medium, what are the three types of computer networks?

Computer networks can be divided into wired networks, optical fiber networks and wireless networks according to transmission media.

1. wired network: refers to the computer network connected by twisted pair.

2. Optical fiber network: using optical fiber as transmission medium.

3. Wireless network: A network that uses electromagnetic waves as a carrier to realize data transmission.

According to the data exchange mode, it is divided into circuit-switched network, message switching network and packet-switched network.

According to communication mode, it is divided into broadcast transmission network and point-to-point transmission network.

According to the coverage and scale of the network, it is divided into LAN, MAN and WAN.

Performance index of extended data computer network

(1) exchange rate

In network technology, rate refers to the rate at which a host connected to a computer network transmits data on a digital channel, also known as data rate or bit rate. Rate is the most important performance index in computer network. The unit of rate is bits per second (bits per second).

(2) Bandwidth

The bandwidth of a signal refers to the frequency range occupied by various frequency components contained in the signal.

(3) Throughput

Throughput refers to the amount of data passing through the network (or channel or interface) per unit time.

(4) Time delay

Latency refers to the time required for data (messages or packets, or even bits) to travel from one end of a network (or link) to the other.

(5) Delay bandwidth product

Multiplying the two indicators of network performance discussed above-propagation delay and bandwidth, we get another useful indicator: propagation delay bandwidth product, instantaneous delay bandwidth product = propagation delay × bandwidth.

(6) Round trip time (RTT)

In the computer network, the round-trip time is also an important performance index, which indicates the total time from the sender to the receiver (the receiver sends an acknowledgement immediately after receiving the data).

(7) Utilization rate

There are two kinds of utilization rates: channel utilization rate and network utilization rate. Channel utilization refers to the percentage of time that the channel is used (data passes through), and the utilization rate of completely idle channels is zero. Network utilization is the weighted average of channel utilization of the whole network.