Practical Skills: Five Fault Diagnosis technologies for vswitches

Welcome to the network technology community forum and interact with 2 million technical staff in an exchange network. How do you determine where to start searching for problems? It is very difficult to look into a "Perspective" exchange network. First, the two-layer switch still uses the bridge forwarding method, but the three-layer switch has more advanced features and forwarding rules, such as VLAN

Welcome to the network technology community forum and interact with 2 million technical staff> go to an exchange network. How do you determine where to start searching for problems? It is very difficult to look into a "Perspective" exchange network. First, the two-layer switch still uses the bridge forwarding method, but the three-layer switch has more advanced features and forwarding rules, such as VLAN

Welcome to the network technology community forum and interact with 2 million technical staff> enter

In an exchange network, how do you determine where to start searching for problems? It is very difficult to look into a "Perspective" exchange network. First, the two-layer switch still uses the bridging forwarding method, but the three-layer switch has more advanced features and forwarding rules, such as VLAN. Layer-4 switching is even more complicated. More advanced forwarding and Server Load balancer technologies are introduced, and more Switch configuration knowledge is required for fault diagnosis and resolution.

After a vswitch is installed, the half-duplex port of each vswitch constitutes a conflict domain. If the port is connected to a hub and several sites are connected under the hub, the conflict domain will expand. However, as the price of switching products declines, most newly created networks now have only one site connected to each switching port. Therefore, in a half-duplex connection, the conflicted domain is only for a single cable link.

A vswitch is usually part of an independent broadcast domain, including any number of other switches connected in series or connected. If the three layers of the OSI model are used, you can create multiple broadcast domains. The number of broadcast domains is equal to the number of VLANs. If the vswitch function permits, each port can be configured as an independent broadcast domain. This situation can be described as routing to the desktop. After creating an independent broadcast domain for each port, the fault diagnosis will be strictly limited. However, if we set each port as a separate broadcast domain, each port needs routing services when the switch forwards traffic, which will occupy limited resources of the switch CPU. In the network environment, it is very difficult to route requests and responses to each separate port. We should avoid such configuration. Unfortunately, this situation is very common in actual situations. In the network, we often find that all servers are in one subnet or broadcast domain, and all customers are in another Subnet or broadcast domain. In this case, all requests must be routed. If the maintenance behavior is restricted to a separate server group, consider placing the server in a separate VLAN. Then, users using this server are placed in the same VLAN. In this way, you can use a two-layer bridge to exchange traffic. Only a few requests require routing. If the server supports more than one user zone, you can install more than one network card on the server to achieve two-layer switch connection to the user.

　　Five technologies for vswitch Fault Diagnosis

You can use five basic methods to view the vswitch. Each method is different and has a positive or negative side. Similar to other problems encountered in the network, there is no best answer. The most appropriate solution often depends on the resources you can use (which tools can be used or which tools have been installed before), and the use of these technologies may cause service interruption.

Even if these methods are combined, the connected network cannot be monitored. In the exchange environment, the monitoring is not as convenient as the hub. It is almost impossible to see all the traffic through one vswitch. Most Fault Diagnoses assume that the traffic passes between the site and the Connected Server or through the uplink port of the fault diagnosis switch. In fact, if two hosts directly transmit information, they will not use the uplink port of the switch or any other port to exchange traffic. Unless you know which port is used, it cannot be monitored.

For example, 1. A server is connected to a vswitch. Some of the users who report problems are directly connected to the vswitch, while others are connected by the uplink port of the vswitch from other vrouters or vswitches. Fault Reports are slow to access servers. Such fault reports are of little value to Technical Support Engineers.

　　

, A basic vswitch Environment

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