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Real-world example: It's a different era now, but a Huawei switch can't connect to a server's network port?

The cases shared in this issue are related to wired network issues.

Background

In an enterprise network, E1 devices (servers) from other manufacturers need to connect to multiple Huawei devices through electrical ports to enable service data intercommunication. The network topology is as follows:

The E1 device is connected to the 10GE0/0/3 interface of Huawei Device1 and the 10GE0/0/4 interface of Device2. The E1 device also has an uplink access port, Interface 3, to connect to other network devices.

The network segments involved are divided and configured according to actual business needs.

The device connection status is displayed:

  • The status of interfaces 10GE0/0/3 on Huawei Device 1 and 10GE0/0/4 on Device 2 are both up.
  • The status of Interface 1 and Interface 2 of the E1 device is always DOWN.

  • The uplink interface 3 of the E1 device is in the UP state.

At this point, services between Huawei devices and E1 devices cannot communicate normally.

Processing ideas

Typically, if the physical link cannot go up, the problem may be related to the transmission medium, device interface, or negotiation mechanism. The solution is as follows:

  • Check whether the transmission medium is normal;
  • Check whether there is a hardware fault on the device interface;
  • Check whether the negotiation modes of the device interfaces match.

Troubleshooting and Analysis

Step 1: Eliminate problems with the transmission medium and the peer device as a whole

In order to determine the problem, I reinstalled the crystal head and replaced the finished cable, but the problem still existed. It was not a problem with the physical link.

Step 2: Check the interface status of Huawei devices

Log in to the Huawei device and run the display interface command in any view to check the interface status. For example, the output on 100GE1/0/1 is as follows:

100GE1/0/1 current state : UP//接口状态为UP无异常
Line protocol current state : UP
Description:MOBILE-AGGREGATION eNodeB=XX Siteid=YYYY Sitename=“CHANGE ME”
Switch Port, PVID : 200, TPID : 8100(Hex), The Maximum Frame Length is 1600
IP Sending Frames‘ Format is PKTFMT_ETHNT_2, Hardware address is xxxx-xxxx-xxxx
Port Mode: COMBO AUTO
Current Work Mode: COPPER Speed : 1000,Loopback: NONE
Duplex: FULL,Negotiation: ENABLE//速率双工模式均正常，协商模式为自协商
Mdi: AUTO， Flow-control: DISABLE
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The output shows that the interface is in physical state Up, the rate is 1000, the duplex mode is full duplex, and it is in auto-negotiation mode.

Step 3: Modify the interface negotiation mode for testing

Based on the previous troubleshooting, we initially suspected that the Huawei device failed to negotiate with other vendors' devices, causing the peer interface to fail to come up normally. We then attempted to run the following command on the corresponding interface on the Huawei device to change the mode to non-auto-negotiation mode:

<HUAWEI> system-view
[~HUAWEI]interface 100ge 1/0/1
[~HUAWEI-100GE1/0/1] negotiation disable  //禁用自协商模式
[*HUAWEI-100GE1/0/1] commit
[~HUAWEI-100GE1/0/1] quit
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After the modification is complete, run the display interface 100ge1/0/1 command again to check the interface status. The relevant information is as follows:

100GE1/0/1 current state : UP//接口状态为UP无异常
Line protocol current state : UP
Description:MOBILE-AGGREGATION eNodeB=XX Siteid=YYYY Sitename=“CHANGE ME”
Switch Port, PVID : 200, TPID : 8100(Hex), The Maximum Frame Length is 1600
IP Sending Frames‘ Format is PKTFMT_ETHNT_2, Hardware address is 0025-9e2c-a271
Port Mode: COMBO AUTO  Current Work Mode: COPPER
Speed : 1000,Loopback: NONE
Duplex: FULL,Negotiation: DISABLE//速率双工模式均正常，协商模式为非自协商
Mdi: AUTO， Flow-control: DISABLE
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At this time, the interface status of the E1 device on the other end becomes UP and services return to normal.

Principles and solutions

(1) Cause of failure

The interface attribute auto-negotiation mechanisms of devices from different vendors differ. This can cause Huawei devices and E1 devices from other vendors to fail to negotiate properly in auto-negotiation mode. As a result, the interface on the peer device cannot go up, resulting in service interruption.

(2) Solution

When connecting a Huawei device to another manufacturer's device, follow these steps:

  • First, set the interface to the default auto-negotiation mode and observe the connection status;
  • If auto-negotiation fails, run the negotiation disable command to change the interface negotiation mode to non-auto-negotiation mode.
  • If the problem persists, run the speed { 10 | 100 | 1000 } command to set the speed to the same as that of the remote end, such as 100 Mbps or 10 Mbps, to ensure that the speeds on both ends of the link are consistent.