How to represent the MAC address capacity in a switch or router

The fact is that the lotus root is seen by the eyes, and the trees are seen.

of the switchMAC addressThe table mainly includes the main parameters: the MAC of the Layer 2 of the switch, and the MAC of the device under the interface, which is matched quickly. The main parameter of a Layer 2 switch is the MAC address table, and the main parameter of a Layer 3 switch is the routing address table.

A communication B establishes a MAC address table through multiple correspondences on the switch, that is, the so-called destination address carried by the packet carried by the source is looking for port B, and it will flood to all other ports except itself. When you get a response, you get the MAC address and interface. The MAC table will have a corresponding relationship between the source and destination interfaces.

The MAC address is established.

Summary. The reason why a switch is able to send packets directly to the destination node.

And not like a hub.

The key technology for sending packets to all nodes in broadcast mode is that the switch can identify the MAC addresses of the nodes connected to the network and put them in a place called the MAC address table.

This MAC address table is stored in the cache of the switch and remembers these addresses, so that when it needs to send data to the destination address, the switch can look up the node location of the shortened MAC address in the MAC address table and send it directly to the node in this location.

Summary. Address learning.

The switch knows the MAC address of the device connected to each port, maps the address to the corresponding port, and stores it in the MAC address table in the switch cache.

The switch is called the MAC address and port in the connected device in the address table.

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There are three main functions of the switch: address learning, filtering, and loopback avoidance.

The switch saves the MAC address and port in the connected device in the address table called address learning.

The address learning exchange machine understands the MAC address of the device connected to each port, and maps the address of the Huai Xiang with the corresponding port and stores it in the MAC address table of the switch cache.

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The switch learns to build its own MAC address table based on the source address.

The switch technology must know the MAC address of the host connected to each port before the first data, and build a MAC address table. When the switch receives a data frame from a port, it reads the destination MAC address information encapsulated in the data frame, and then consults the pre-built MAC address table to find the port corresponding to the destination address, and sends the data out from the port, and other ports are not affected, so as to avoid collision with the data on other ports.

Suppose that host A sends a data frame to host C, and when the data frame enters the switch from port E0, the switch checks the source MAC address field in the data frame, puts the value of the Shanhaoxian field into the MAC address table, and corresponds it to port E0, indicating that the host connected to port E0 is A. At this point, since there is no entry in the MAC address table for the destination MAC address, the switch technology teases to send this frame to all ports except port E0**, thus ensuring that host C receives the frame.

The switch is based on the address table ** data

When the switch establishes a complete MAC address table, the corresponding port is obtained by looking up the MAC address table for the data frame, so that the data frame is sent out through a specific port. For broadcast data coming in from one port and for data for which no address entry is found in the address table, the switch will egress the data frame from all ports except the incoming port**. From this perspective, the devices that the switch interconnects are in the same broadcast domain, but they are in different collision domains.

The MAC address table is created by assuming that A sends a data frame to C, but this is not the case, and the switch must communicate with each other to learn the MAC address. In fact, when the NIC driver is loaded, the switch learns the MAC address of the host, and if you look closely, you will find that the Windows system boot process has not yet been completed, and the switch technology learns the MAC address of the host.

To put it simply, the MAC address of a switch port is generally fixed, while the routing table of a router is divided into static and dynamic.

Routed! You can set it up yourself! Switches are dead! Fixed! Actually, the function is the same!

The router's routing table stores IP addresses and interface numbers, which are layer-three.

The MAC address table of the switch is Layer 2 and stores the MAC address and interface number.

Although they are all addresses, they are at different levels in the network architecture.

1. The router has two MAC addresses, one for WAN port and one for LAN port.

2. The switch does not have a MAC address, it is only responsible for bridging.

Home routers are mainly used for broadband sharing, that is, one broadband is provided to multiple networked devices to access the Internet at the same time.

There are two routers, one on the external network and one on the internal network, and the switch does not have a MAC address.