CCNA Learning Notes: network equipment

Repeater

Its function is to relay the signal and copy and forward the electronic signal. The general application scenario is that the distance between the devices is relatively long, which exceeds the maximum distance of the transmission medium, and the signal can be relayed through the repeater to achieve signal transmission.

Hub

Its function is the same as the repeater: copy the signal and forward it.

The difference: the hub has multiple ports, and all received signals are forwarded to other ports.

Hubs are generally used for component star topology networks between multiple devices.

Network bridge

Parse the destination MAC address in the frame

If forwarding to another port can reach that address, the signal is regenerated and forwarded

If the port itself can reach the address, it is discarded.

Bridges are generally used for links between different conflicting domains in a local area network.

Exchanger

The function of a switch is similar to that of a bridge, except that it supports multiple ports.

A switch table is maintained in the switch, the mapping of device MAC addresses to ports is kept, and frames are forwarded and filtered based on MAC addresses.

5.WLAN access Point AP

The function is similar to the switch, using wireless communication.

6. Router

The router is responsible for routing packets from the sending computer to the receiving computer.

When we often surf the Internet, when we communicate with the server, the most devices that send messages are routers.

The NAT mode of the router: refers to the network address translation between the internal network and the external network, and there is no routing exchange between them.

The DMZ of a router can be understood as a special network area, and the external network can also be accessed. It is common to place some public services that do not contain confidential information.