Is the smart S3 floor switch fully functional?

The most important function of a layer-3 switch is to speed up data forwarding within a large local area network. The routing function is also used for this purpose, which reduces the data transmission speed, added network latency.

After the status of the switch and the cascade port status are ruled out, the network administrator starts to suspect the cascade port configuration of the S3 floor switch, because S3 floor switches used 1 switching port for Cascade with core switches, they now use 2 switching port for Cascade with S4 floor switches.

Will the following virtual working subnet need to be re-divided and configured after the cascade Port location changes? The network administrator wants to first compare the parameter configurations between the switch 1 and switch 2 on the S3 floor switch, he immediately logged on to the S3 floor switch background management interface according to the previous operation method.

In the global configuration status, execute the string commands "display interface ethernet 0/1" and "display interface ethernet 0/2" in sequence, and then carefully compare the results returned by the two commands. After careful comparison, the Network Administrator finds that the "Port link-type" value of Port 1 is "trunk", and the "Port link-type" value of Port 2 is "access ", is the change in the connection type of the switch port causing the virtual working subnet under the S3 floor switch to be unable to normally access the Internet?

After online search, the network administrator finds that for manageable vswitches, each switching port can be set to three different link types: Access, Trunk, and Multi, the Access-type switch port allows only one virtual working subnet to pass through. It is usually used to connect to a common computer. The Trunk-type switch port allows multiple virtual working subnets to pass through.

It is usually set on the cascade port, while the Multi-type switching port can allow one virtual working subnet to pass through, but also allow multiple virtual working subnets to pass through at the same time, it is mainly used to connect both a vswitch and a common computer. We can enable different connection types in the same vswitch.

Only switch ports of the Trunk type and switch ports of the Multi type cannot be directly switched to each other. The switch ports must pass through the Access type before they can be switched to each other. According to the above analysis, the network administrator can easily find the specific root cause of the above fault.

That is, when the S3 floor switch uses the 2 switch Port for Cascade With the S4 floor switch, the "Port link-type" parameter of the 2 switch Port is improperly set, as a result, multiple virtual working subnets under the corresponding vswitch cannot access the network through the 2 switching port.

Tip: Trunk is an encapsulation technology. It is a point-to-point link. Its main function is to connect multiple switches through only one link to expand the configured virtual working subnets; at the same time, the Trunk link can be connected to a vswitch, A vro, or a special server Nic ).

The number of interfaces can also be expanded through the Trunk technology and the cascade mode of the upper-level switch, which can achieve the function of approximate stacking, saving the cost of network hardware. In addition, the Trunk link does not belong to any virtual working subnet. It only plays a role in the network.

The virtual working subnet range carried by the Trunk. The default value is 1 ~ 1005, which can be modified, but must have 1 Trunk protocol. When using Trunk, the protocols on the two vswitch connection interfaces must be consistent. Interfaces configured as Trunk links are generally the bandwidth ports that support the maximum bandwidth on the switch.

Troubleshooting

After finding out the specific cause of failure, the failure of multiple virtual working subnets that cannot access the Internet can be well solved. The Network Administrator only needs to modify the configuration parameters of the S3 floor switch, change the "Port link-type" parameter of Port 2 from "Access" to "Trunk, in this way, the virtual working subnet divided on the S3 floor switch 5 and the virtual working subnet 6 can access the Internet through the 2 switching port.

When you modify the connection type parameter of Switch Port 2 on S3 floor, the network administrator first directly connects to the target switch through the Console control cable, and then logs on to the background management system as the system administrator, then run the string command "system" to switch to the global configuration status of the corresponding switch system;

Next, run the "interface ethernet 0/2" string command in the global state to enter the view configuration mode of Port 2, in view mode of the target switch port, enter the string command "port link-type trunk" and click the Enter key, the link type of Port 2 of the S3 floor switch is changed to "trunk ";

To allow all the virtual working subnets under the S3 floor switch to access the Internet through the Trunk port, the Network Administrator continues to execute the string command "port trunk permit vlan all" in the view configuration mode of port 2, so that no matter how many virtual working subnets are divided on the S3 floor switch.

You can access the Internet through the destination switch port. After the preceding configuration task is completed, the network administrator finally runs the string command "save". On the System screen, the Operation prompt shown in 3 is displayed. Click the "Y" key on the keyboard, in this way, the S3 floor switch system automatically saves the above settings.

In the same way, the Network Administrator logs on to the S4 floor switch and changes the cascade port connection type used to connect to Port 2 in the background to "Trunk ". At the end of the Internet test, all the virtual working subnets under the S3 floor switch can access the Internet normally, and thus the failure caused by the cascade port change will be ruled out successfully.

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