Basic knowledge: The difference between bridge and Internet Connection Sharing

ICS (Internet Connection Sharing) is an Internet Connection Sharing service provided by Windows for a home network or a small Intranet network. It is actually equivalent to a network address converter, the so-called network address converter is when the packet forward process, you can switch the IP address in the packet and TCP/UCP port and other address information. With the network address converter, a private address can be used on a computer in a home network or a small office network, in addition, the network address converter converts a private address to a single public IP address allocated by the ISP to achieve Internet connection. ICS is also called an Internet conversion connection.

Bridge) like a smart repeater. A repeater receives signals from a network cable, scales them up, and sends them to the next cable. They do not care about the content of the messages they forward. In comparison, bridges are more sensitive to Information uploaded from checkpoints.

The bridge connects two similar networks and manages the circulation of network data. It works on the data link layer, which not only expands the distance or range of the network, but also improves the network performance, reliability, and security. After network 1 and Network 2 are connected through a bridge, the bridge receives the packet sent by network 1 and checks the address in the packet. If the address belongs to network 1, it will discard it. On the contrary, if it is the address of Network 2, it will continue to be sent to Network 2. in this way, the bridge isolation information can be used to divide the network into multiple CIDR blocks and isolate the CIDR blocks to prevent unauthorized access from users in other CIDR blocks. Due to the segmentation of the network, each network segment is relatively independent. The failure of one network segment does not affect the operation of another network segment.

A bridge can be a specialized hardware device or a bridge software installed on a computer. Multiple network adapter NICs are installed on the computer ).

The function of the bridge is similar to a repeater in extending the network span. However, it can provide intelligent connection services, that is, forwarding and filtering based on the network segment of the end address of the frame. The bridge's understanding of the network segment of the site relies on "self-learning.

When a bridge is used to connect two LAN segments, the bridge must first check its endpoint address for MAC frames from CIDR Block 1. If the frame is sent to a station on CIDR Block 1, the bridge filters out the frame instead of forwarding it to CIDR Block 2; if the frame is sent to a station on CIDR Block 2, the bridge forwards it to CIDR Block 2. this indicates that if a user on LAN1 and LAN2 communicates with each other on this segment at the same time, it is obviously feasible. Because the bridge is isolated. It can be seen that the bridge has the function of increasing network bandwidth under certain conditions.

Compared with the repeater, the storage and forwarding functions of the bridge have the following advantages:

Bridging eliminates physical limitations, which means that the total number of data stations and CIDR blocks that constitute the LAN can be easily expanded.

The storage and forwarding functions of the bridge allow the bridge to be used to connect two LANs using different MAC protocols, thus forming a hybrid network environment in which different LANs are connected together.

The relay function of the bridge only depends on the address of the MAC frame, so it is completely transparent to the high-level protocol.

The bridge divides a large LAN into segments, which improves reliability, availability, and security.

The main disadvantages of the bridge are:

Because the bridge receives frames and caches them before performing forwarding, more latency is introduced than the repeater.

Because the bridge does not provide the traffic control function, it may overload the traffic, resulting in Frame loss.

The advantages and disadvantages of a bridge are the reasons for its widespread use.

1. Differences between wireless routing, AP, and bridge