Clever Use of the Bridge Function in Windows XP Network

After Microsoft officially launched Windows XP, the most intuitive feeling was that the style of its operation interface had changed significantly. When we opened windows XP's Huawei edition and explored its new applications, we will find that in addition to providing extensive multimedia support, Windows XP has also made significant improvements in its network functions.

In the "Network Connection" project of "Control Panel", the connection types are generally divided into "LAN or high-speed Internet connection" and "dial-up connection. If an Eni is installed on your computer, a "Local Connection" icon appears in the "LAN or high-speed Internet connection" project, after several NICs are installed on your computer, several connection icons are displayed. Select a connection icon, right-click the shortcut menu, and you will find that there is an additional "bridge" option in the menu, which has never been seen in previous Windows versions, what does it do?

This article will explain how to implement the "bridge" function. The operating system used by the author is Windows XP Professional. The installed NICs include two 3Com 3c905c, one 1394 network adapter, and two Cisco Aironet Wireless NICs.

I. Operation Guide

1. Create a bridge

As the name implies, "bridging" is a connection implemented by a bridge. The bridge works on the Layer 2 (data link layer) of the OSI reference model. It only focuses on the MAC address, not the transmission protocol. Based on the Site or MAC address, the bridge divides the network traffic into several segments and filters them out. Network adapters that can be bridge include 10/100 Mbps Ethernet adapters, the latest 1394 network adapters, wireless network adapters, and other Ethernet compatible adapters. The procedure for implementing the "bridge" function is as follows.

(1) Open the network connection project in Control Panel.

(2) In the "LAN or high-speed internet" project, 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 the bridge option (1 ).

After a connection process, a new bridge is created (2 ). If you are not clear about the concept of a bridge, consider it as a switch with only two ports. It is particularly worth noting that the bridge itself can also configure an IP address, but this IP address has nothing to do with the bridging effect, even if it is not in the same subnet with the two connected LAN, two local networks can communicate with each other.

2. Add the connection to or delete the connection from the bridge.

(1) Open the network connection project in Control Panel.

(2) Select the "properties" option in the shortcut menu of the "bridge" project. The "Network Bridge properties" dialog box is displayed (3 ).

(3) In the "adapter" project on the "General" tab, select the check boxes for each adapter to be added to the bridge, and click "OK.

The process of deleting a connection from a bridge is the opposite of the above process. But pay attention to the following points when performing this operation.

(1) only one bridge can be created on a computer, but the bridge can accommodate numerous network connections.

(2) You cannot create a bridge on a computer running Windows 2000 or earlier.

(3) 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.

Ii. Typical applications

1. Bridging

Of course, the most basic application of bridging is to connect two local networks. The Network shown in Figure 4 contains two local networks, all of which use a hub-centered star topology and are connected to each other by a bridge computer with two NICs. When Server 1 tries to communicate with server 2, the data packet is forwarded to all ports in broadcast form by the hub. After receiving the data packet, the bridge computer finds that machine 1 and machine 2 are in the same lan 1 through querying their address list, therefore, the bridge will not broadcast packets for communication between machine 1 and machine 2 to lan 2. The bridge computer uses address filtering to implement traffic isolation and segmentation of conflicting domains.

The basic bridging function can generate many changes in specific applications based on the actual environment. For example, if a computer is far away from the hub (100 m above the Ethernet requirement), you can use a computer that is closer to it to create a bridge to act as a repeater and include the computer in the LAN.

2. Three-host Interconnection

Many of my friends need ~ When four computers are connected, the common solution is to purchase a small hub to connect to the network. In fact, when the number of computers to be connected is small, you can use a computer with a dual Nic to act as a bridge to connect to each computer.

In the past, this scheme was implemented by configuring a computer with a dual-nic into a path by a computer, which actually utilizes the switch function of the router. As we all know, the packet exchange function of a vro is essentially different from that of a vswitch. Data Packets passing through the vro must be disassembled and re-encapsulated each time. Therefore, there is a gap between the exchange efficiency of the vro and the exchange efficiency of the pure storage and forwarding type of the vswitch. In addition, complicated system routing needs to be configured through this method, which is not an ideal solution.

In Windows XP, this problem becomes very simple. You only need to create a computer with two NICs as a bridge to interconnect multiple computers, which is very convenient. The specific operation method is shown above.

3. Construct a wireless network access point (acesspoint)

With the bridging function of Windows XP, we can use a wireless network card and a common Ethernet card to implement the wireless network access point function (5 ). In a bridge computer, create a bridge using a wireless network connection working in ad-hoc mode and an Ethernet connection, in this way, wireless network terminals working in ad-hoc mode can access wired Ethernet through a bridge computer. If you have opened wireless network access points or bridge devices, you will find that they are actually inserting a wireless network card into a circuit board integrated with an Ethernet card, then, bind the wireless network card and the ethernet card to the same IP address, which is similar to what we have done above.

4. Link Redundancy

In addition to dual-Machine backup, most servers that require high communication link reliability also adopt dual-link redundancy with switches. A Redundant Dual-link is used between the server and the switch. One of the links does not work normally. The backup link is enabled only when the master link is disconnected due to a fault. This design is based on the dual network card system on the server, which is traditionally implemented using a dedicated network card. However, in Windows XP, we can use the bridge function to implement dual-link redundancy.

The traditional dual-nic solution is essentially an application of cluster technology. Two NICs have one chip to coordinate with each other.ProgramIf the secondary ENI is enabled, the secondary ENI is automatically disabled. The dual-link redundancy implemented by the bridge computer uses the bridge computer as a switch and enables the spanning tree here.AlgorithmCreate a non-circular forwarding topology. This ensures that the forwarding topology is non-circular, thus avoiding the occurrence of a forwarding storm.