Bridge in Win XP

Bridge in Win XP
The term bridge sounds familiar and unfamiliar. What is it? In fact, a bridge is a cheap and convenient way to connect LAN segments. To understand how bridges work, you must first understand the LAN segments. A lan segment is a single part of the network media that connects to a computer. For example, assume that you have three computers: computer A, computer B, and computer C. Computer A has two Ethernet cards, and computer B and C each have an Ethernet Card. An Ethernet cable connecting a and B creates a LAN segment. Another ethernet cable connecting A and C will create another LAN segment.

Traditionally, If you need multiple network segments, you have two options: routing and bridging. IP routing is a common solution for connecting network segments. However, if you want to install an IP route, you need to purchase a hardware router or install a computer at the intersection of segments to use it as a router. For each computer on each network segment, IP routing requires complicated configuration of IP addressing, and each network segment must be configured as an independent subnet. IP routing is a solution suitable for large-scale networks. In this case, scalability is very important and requires experienced personnel to configure and maintain the network. The hardware bridging solution does not have to be configured as complicated as IP routing, but it requires an additional hardware bridge. If you are using a home network or a small office network, neither of these two options is ideal. You do not want to buy expensive bridging hardware, or ask experienced personnel to manage IP routing networks.

Instead, the bridge allows you to connect to a LAN segment by selecting the appropriate network connection icon and clicking "bridge. Similar buttons allow you to enable a bridge and add a connection to the bridge. The bridge manages the LAN segments of the entire network and creates a single subnet. No configuration is required, and no additional hardware (such as a router or bridge) is required ). In a single subnet IP address network, IP addressing, address allocation, and name resolution are highly simplified.

Bridges can create connections between different types of network media. In a traditional network, if the hybrid media type is used, each media set requires a separate subnet and data packet forwarding between multiple network subnets. Because different media types use different protocols, data packet forwarding is required. The bridge automatically performs the required configuration to forward information from one media type to another.

Windows XP has only one bridge, but can be used to bridge the network connections actually allowed by all computers.
Bridge uses the IEEE Spanning Tree Algorithm (STA) to establish a non-circular forwarding topology. When multiple paths exist in a bridge network, loops can be formed, and simple forwarding rules of the bridge will cause a forwarding storm, that is, there will be no end-to-end relay between one frame and the other. STA provides an automatic mechanism to selectively disable bridge forwarding on a single port when necessary to ensure that the forwarding topology is non-circular. Bridge is not required for Spanning Tree algorithms.

After talking about that, how do common users install and set up and use Bridges? Let me explain in detail:

1. Create a bridge:

1. open "network connection" (to open "network connection", click "start", point to "Settings", double-click "Control Panel", and click "network and Internet connection ", click "network connection ").
2. Under "LAN or high-speed internet", select each private network connection that you want to use as a part of the bridge.
3. Right-click one of the highlighted private network connections and click "bridge ".

2. Add the connection to the bridge

1. Open "network connection ".
2. Under "bridge", right-click "bridge" and click "properties ".
3. Under "adapter" on the "General" tab, select the check box for each adapter to be added to the bridge and click "OK ".

3. enable or disable Bridges

1. Open the network connection.
2. Under "bridge", right-click "bridge" and select one of the following operations:
3. To enable "bridge", click "enable ".
4. To disable "bridge", click "Disable ".

4. Delete the connection from the bridge

1. Open the network connection.
2. Under "bridge", right-click "bridge" and click "properties ".
3. Under "adapter" on the "General" tab, select the check box next to the adapter you want to delete and click "OK ".

However, you must log on as an administrator or a member of the administrators or Administrators Group to complete the process. If the computer is connected to the network, the network policy setting can also prevent you from completing this step. You must select at least two qualified network connections to use "bridge" to create a bridge; an adapter with Internet Connection Sharing (ICS) or Internet Connection Firewall (ICF) enabled cannot be part of a bridge or appear in the bridge list. Similarly, the "add to bridge" menu command applies only to adapters that can be added to bridges as connections; Only Ethernet, IEEE-1394 adapters, or Ethernet compatible adapters such as wireless, and the home phone line adapter (hpna) can be part of a bridge. If ICF or Internet Connection Sharing (ICS) is not enabled, do not create a bridge between a public Internet connection and a private network connection, you can also add a public Internet connection to an existing bridge. This will create unprotected links between your network and the Internet, so your network is vulnerable to attacks. Only one bridge can be created on one computer, however, this bridge can accommodate countless network connections. It cannot create a bridge on a computer running Windows 2000 or earlier. If there are fewer than two adapters deleted from the bridge, the bridge will not perform the expected functions, but will continue to use system resources. When a network adapter previously displayed in "LAN or high-speed internet" is added as a connection, it will appear under "bridge. Network adapters that provide Internet connections (such as DSL and Cable Modem) cannot be bridging and will always appear under "LAN or high-speed internet"; before enabling a bridge, you must use "bridge" to create a bridge. If the bridge is disabled, computers on the network cannot communicate with computers on other network segments. Some computers on the network may also interrupt Internet connections. If the adapter is deleted from the bridge and there are less than two retained adapters, the bridge will not perform the expected functions, but will continue to use system resources; at least two adapters must be connected to the bridge to ensure its functionality. If the "Network Connection" folder is enabled, you can also delete the network connection from the bridge. Under "bridge, right-click the adapter you want to delete, and then click "delete from bridge". If you delete the adapter from the bridge and there are fewer than two retained adapters, the bridge will not perform the expected functions, however, system resources will continue to be used. Bridges connected using wireless or IEEE-1394 only support communication using Internet Protocol Version 4 (IPv4); Internet Connection Sharing, Internet Connection Firewall, discovery and control, and bridges are available in Windows XP 64-bit edition.

So what kind of effect does the bridge achieve and what is the application value? In fact, a bridge can be used to establish a bridge group policy. The principle is that the "bridge" enables the Computer Administrator to create a bridge between two or more networks, enable network communication through all network connections included in the bridge, as if all these connections are part of the same network subnet. The "Group Policy" setting defines various components of the user desktop environment that the system administrator needs to manage. You are prohibited from installing and configuring on your DNS domain network. Use a bridge to determine whether a computer user with administrative permissions can enable "bridge" on the DNS domain network ".

The "bridge" menu command "bridge" is available only when two or more network adapters exist. By default, "bridge" is disabled, but the administrator can enable it using the menu on the network connection icon. If start? Quot; do not install or configure on your DNS domain network. Use bridging to disable "bridging" on the domain network ", because the "bridge" command has been deleted from the network connection Icon menu, you cannot create a "bridge ". Prohibit computer users with limited permissions from configuring "Bridges", regardless of what the setting is.

If a "bridge" already exists in the computer on the network before the policy is enabled, the bridge will continue to exist because the setting knows the location. This setting is applied only when the computer is connected to the same DNS domain network that the last time this setting was refreshed. If your computer (such as a laptop) is connected to your DNS domain network, but the last refresh of this setting on your computer is performed on another network, the settings on your network are not applied to this computer.