What are the requirements for physical layer interconnection of various networks?

Various networks require the same data transmission rate and link protocol when interconnecting at the physical layer; the data transmission rate refers to the speed at which a device or network component can send and receive data, and the link protocol refers to A set of rules for transmitting data over a link. The link protocol and data transfer rate must be the same for interconnection.

The operating environment of this tutorial: Windows 10 system, DELL G3 computer.

What do various networks require when interconnecting at the physical layer?

Various networks require the same data transmission rate and link protocol when interconnecting at the physical layer

Data transfer rate (DTR) refers to the speed at which a device or network component can send and receive data. This may also be referred to as throughput, the data transfer rate that applies specifically to digital data streams.

Link protocol refers to a set of rules for transmitting data through a link, including rules for establishing, maintaining, and disconnecting links, as well as the control information format for transmitting data on the link, and the control Rules for interpreting information

When connecting at the physical layer, if the protocol is the same but the data transmission rate is different, there are two situations: First, the sender's rate is higher than the receiver, and overflow will occur because the receiver is too late to receive. ,data lost. Second, the receiver's speed is higher than that of the sender. In this case, there will be no data loss, although the efficiency is relatively low. But in summary, communication is a process of interaction between two parties, and in any case, the described data loss situation will occur.

This is because when connecting at the physical layer, there is no room for buffering in the middle, and the two parties must match the rate. There is a certain buffering mechanism above the data link layer. Even if the rates do not match, normal communication can still be achieved as long as it is within the processing capabilities of the corresponding network equipment.

Extended knowledge

Data transfer rate

Data transfer rate refers to the amount of data transmitted by the data path per unit time. It usually includes three aspects:

1. Data signal rate, which represents the number of bits of data information transmitted in one second, in bits/second (b/s).

2. Modulation rate. Modulation rate reflects the frequency of signal waveform transformation. It is defined as the number of signal symbols (waveforms) transmitted per second, also known as symbol rate, symbol rate or baud rate. The unit is baud.

3. Data transmission rate represents the average number of bits, characters or information groups passed per unit time between two corresponding devices in the data transmission system. Its unit can be bits, characters or information groups per second, minute or hour, and the corresponding device refers to a modem, intermediate device or data source. Transfer rates can be applied to different functions. Latency times can help network administrators pinpoint where in the network there are slowdowns and potential blocks. By analyzing data transfer rates and adjusting accordingly, the system can run more efficiently as a protective measure and prevent special bandwidth limitations during periods of high load. Test equipment such as fiber optic loop testing can help measure and manage data transmission rates.

Link protocol

A link refers to a line or channel that connects two nodes in the network. A link protocol refers to a set of rules for transmitting data over a link, including rules for establishing, maintaining, and disconnecting links, as well as the format of control information for transmitting data on the link, and the rules for interpreting control information [ 1] .

It supports two types of links:

1. Point-to-point - between pairs of devices;

2. Point-to-multipoint - one node Communicate with several nodes;

At this stage, all link protocols are based on IBM's Synchronous Data Link Control (SDLC). For WAN links, SDLC is still the main system network structure (SNA) link layer protocol. The first standard link protocol based on IBM's SDLC protocol was the High-Level Data Link Control (HDLC) adopted by ISO. ITU-T subsequently modified the high-level data link control and established the Link Access Procedure (LAP), and then It is the Balanced Link Access Procedure (LAPB)

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