Differences between physical layer bandwidth and MAC layer bandwidth

Hello! It's simple:

Based on the physical layer, the characteristics and conditions of the electrical appliances are guaranteed. That is to say, this is a big premise. In practice, your network can support wireless speeds of up to 54Mbps, at least physically.

The MAC sub-layer of the link layer is based on protocol and device interconnection, that is, when different network devices are connected to each other, they must use mutually agreed compatible rates and protocols.

Since one of the working principles of network equipment is [by fine matching], so although there are two rates here, what is really used by the device is the more detailed MAC layer protocol rate, from this point of view, your understanding is correct. Above.

The MAC address and physical address of the computer are the same and there is no difference.

MAC English Media Access Control or Medium Access Control, transliterated as **Access Control.

The MAC address is determined by the NIC and is fixed.

In the OSI model, the third layer network layer is responsible for IP addresses, and the second layer is responsible for MAC addresses.

So a host will have a MAC address, and each network location will have an IP address that is unique to it.

The physical address of a network card is usually the EPROM (a flash memory chip, usually written by a program) burned into the network card by the network card manufacturer, which stores the addresses of the computer that really identifies the computer that sent the data and the host that received the data when transmitting data.

In the physical transmission process at the bottom of the network, the host is identified by the physical address, which must be unique in the world.

The medium characteristics of the physical layer include the throughput and bandwidth of the computer network, the cost, the size and scalability, the connector, and the noise immunity.

1. Throughput and bandwidth.

Probably the most important factor to consider when choosing a transmission medium is throughput; Throughput is the amount of data that a medium can transmit in a given period of time, in mb s.

Bandwidth is a measure of the difference between the highest and lowest frequencies that a medium can transmit, usually expressed in Hz.

Second, the cost. Variables that affect the final cost of adopting a certain type of media:

installation costs; the cost of the new infrastructure to reuse the existing infrastructure; maintenance and support costs; the cost of compromising productivity due to low transfer rates; The cost of replacing obsolete media.

3. Size and scalability.

The three specifications (maximum number of nodes per segment, maximum segment length, and maximum network length) determine the size and scalability of the network medium.

Fourth, connectors.

It is the hardware that connects the cables to the network equipment, and each network medium corresponds to a specific type of connector.

5. Noise immunity.

Regardless of the medium, there are two types of noise that can affect their data transmission: electromagnetic interference (EMI) and radio frequency interference (RFI).

The main function of the physical layer: to provide a data path for data terminal devices and to transmit data.

1. Provide a channel for data transmission for data devices, which can be a physical path or a plurality of physical connections.

A complete data transfer at once, including activating the physical connection, transferring data, and terminating the physical connection. The so-called activation means that no matter how many physical ** participate, it must be connected between the two data terminal devices of communication to form a path.

2. To transmit data, the physical layer should form an entity suitable for data transmission needs to serve data transmission. One is to ensure that the data can pass through it correctly, and the other is to provide sufficient bandwidth (bandwidth refers to the number of bits that can pass through per second) to reduce congestion on the channel.

The data can be transmitted in a way that meets the needs of point-to-point, point-to-multipoint, serial or parallel, half-duplex or full-duplex, synchronous or asynchronous transmission.

3. Complete some management work of the physical layer.

Complete the transmission of the most original bitstream, i.e. 0 1

The differences between shared LAN and switched LAN are: different conflict domains, different communication, and different connectivity.

First, the conflict domain is different.

1. Shared LAN: All ports of the shared type are the same conflict domain.

2. Switched LAN: Each port of switched LAN is an independent conflict domain.

Second, communication is different.

1. Shared LAN: All users in the shared LAN share bandwidth, and the actual available bandwidth of each user decreases with the increase of the number of network users.

2. Switched LAN: Switched LAN provides each user with a dedicated information channel, unless two source ports try to send information to the same destination port at the same time, otherwise each source port and their respective destination ports can communicate at the same time without conflict.

Third, connectivity is different.

1. Shared LAN: Shared LAN connects all PCs through the shared medium of bus.

2. Switched LAN: Switched LAN divides different network segments through VLAN (virtual LAN), so that PCs in the same network segment can be connected.

A shared LAN uses physical layer devices, such as hubs, where all ports are in a collision domain and share bandwidth. The switched type uses a switch, each port is an independent collision domain, and uses a large backplane bandwidth and hard switching, and the connection between each port can enjoy exclusive bandwidth, which can generally reach line speed.

1SharedUsually refers to a LAN built using a hub (hub)2

Switched usually refers to a local area network built using a switch3

It is mainly the equipment used that determines the nature. The hub itself is shared, and the switch is switched.