Redirection to the Service Router Fails After Login to the Console Server Through Telnet

Multiple AR2200 routers (RouterB, RouterC, and RouterD) have been deployed in a branch to function as service routers. To improve security, users can only access the service routers through the Console port.

An AR2200 router (RouterA) equipped withthe 8AS interface card has been deployed to function as the Console server, so that users can be redirected to the service routers after Telnet to RouterA to perform management and configuration works.

Figure 1-1 shows the topology.

Figure 1-1 Topology diagram



After the configuration is complete, RouterA fails to redirect users to the service routers after they log in to the Console server through Telnet. 

1. Check the current configuration. For detailed configuration, see "Configuring the Asynchronous Interface."

2. Check the Telnet redirection connection between HostA and the Console server on the Console server.

Run the following command:
<Huawei> display tcp status

If the command output shows that the connection status is Established, the TCP connection has been established.

3. Check the AS interface status.

Run the following command:

[Huawei]display interface brief   
InUti/OutUti: input utility/output utility
Interface PHY Protocol InUti OutUti inErrors outErrors
Async2/0/0  up   down    0%  0.75%     525        0   
Async2/0/1  up   down    0%  0.75%     6525       0  
Async2/0/2  up   down    0%  0.75%     6525       0  
Async2/0/3  up   down    0%  0.75%     6525       0  
…

In the command output:

− If PHY is displayed as up, but Protocol is displayed as down, the related redirection configuration might be incorrect.
− If an interface is displayed under inErrors, the AS cable (reconstructed from a normal RJ45 cable) might be faulty.

4. Check the redirection configuration of the AS.

5. Check whether the AS cable is correctly connected. Connect the network cable connector connecting the Console server to a service router. If the fault still persists, repeat Step 3 and check the command output.

6. Check the pin assignment of AS cable connectors. The end connecting to the Console server uses Async interface pins (X1 pins), and the other end connecting a service router uses Console interface pins (X2 pins). Check the pin assignment of the X1 pins, and the result shows that the pin assignment is different from that specified by the AR router.

Table 1-1 describes the pin assignment specified by the AR router.

Table 1-1 Pin assignment specified by the AR router



Table 1-2 shows the pin assignment of the AS cable specified by the AR router.

Table 1-2 Pin assignment of the AS cable



7. Make new AS cables according to the pin assignment specified by the AR router.

8. Connect the X1 end of the AS cable to the 8AS interface card (Console server), and the X2 end to a service router. The login succeeds, and the fault is rectified.

The ping assignment of the AS cables does not match that of the connected terminals because the pin assignment for normal AS cables is used. Therefore, the protocol status cannot be Up.
The Console server and service routers are AR2200 routers, so the corresponding AS cables for the AR2200 routers are required.

When an AR2200 router equipped withthe 8AS interface card functions as the Console server, special AS cables are required to enable the AR2200 to redirect users to service routers connected to it.

To obtain a special AS cable for the AR2200, change one end of the common straight-through cable to the pin assignment specified by the AR2200.

Note:
 Different terminals use different pin assignments. The AR2200 router is used as an example.
 To use another device as the Console server and managed device, users need to make a corresponding AS cable for the device.