Principle and application of TCP/IP protocol Note 15: Network connectivity Devices

1. Network Connection device:

(1) Transponder repeater/Hub Hub

(2) Bridges Bridge/Switch switches

(3) Router Router

(4) Gateway Gateways

2. View network connectivity Devices from a communication perspective:

(1) Transponder/hub: ( forwarder/ Hub forwarding data only occurs in the physical layer, complete the transmission of the bit data in the physical layer)

A transponder is a kind of network equipment that reconstructs incoming electronic, wireless, or optical signals. The connection of physical layer is realized, and the attenuation signal is enlarged, shaped or regenerated, which plays a role in extending the distance of the network segment.

You can also connect this way:

(2) Bridges/Switches

A switch is a network device used for the forwarding of electrical signals. It provides a unique electrical signal path for any of the two network nodes that access the switch.

The data exchange between a--d is not in the network Bridge, because the two are connected at the same endpoint of the bridge.

• data exchange between a--g into the bridge , because the two are connected at different endpoints of the bridge.

Connection mode:

(3) Router

Routers are devices used to extend and extend the network.

The data interchange route between A--h is as follows:

(4) Gateway

gateways (Gateway) are also known as inter-network connectors, protocol converters. Gateway on the transport layer to achieve network interconnection, is the most complex network interconnection devices, only for two high-level protocols different network interconnection .

A gateway is a computer system or device that acts as a transformation task. The gateway is a translator between two systems that use different communication protocols, data formats or languages, and even architectures that are completely different. Unlike bridges, which simply convey information, the Gateway will repackage the information received to suit the needs of the intended system. The gateway can also provide filtering and security features. Most gateways run on the top layer of the OSI 7 layer protocol-the application layer.
As we all know, walking from one room to another must pass through a door. Similarly, sending information from one network to another must pass through a "gateway", which is the gateways. As the name implies, the gateway is the "gate" of a network connected to another network.

The gateway is required for communication with different protocol stack networks, as follows:

Principle and application of TCP/IP protocol Note 15: Network connectivity Devices