A solution that cannot be opened by a POS link

Introduced is the POS link can not open the solution, the reason is C2 byte mismatch, here to Huawei router for the networking environment.

First, the network environment

Router A has a GE interface and a 2.5G POS interface that connects to other routers, and after starting router A, the GE port status is turned on normally, but 2.5G POS ports cannot be opened.

1, the POS interface configuration is as follows:

Interface pos7/0/0

Undo Shutdown

Link-protocol HDLC

Undo Scramble

IP address 10.112.0.1 255.255.255.252

2, check the system log, found that there are alarms:

Srm/1/labelmismatch:oid=1.3.6.1.4.1.2011.2.17.0.145,index=67109638,slotnum=7,subcardnum=0,portnum=0, receive Path Signal Label mismatch!

Second, failure analysis

1, check the configuration of the link layer protocol: Other routers of the POS port default link layer protocol is HDLC, and the router's POS port default link layer protocol for PPP, look at both ends of the link layer protocol, found that routers have been configured Link-protocol HDLC, and end-to-end configuration of the link protocol consistent , so the judgment is not a problem caused by a protocol mismatch.

2, check the CRC calibration configuration: The default parity of other routers 16-bit CRC checksum, and the router default bit 32 bits, and the router does not support the modification, you need to modify the CRC checksum of other devices to 32 bits. Look at the configuration on the end and find that you have configured the command CRC 32 under its corresponding interface. The CRC checksum configuration at both ends is also consistent, so it is not a problem caused by a CRC checksum mismatch.

3, check the link scrambling configuration: The other device defaults are not scrambling, the router defaults are scrambling, need to adjust to the same. Look at the configuration at both ends and find that the undo scramble has been configured on the router, blocking the scrambling, and therefore not an issue caused by an scrambling configuration inconsistency.

4, check the physical layer of the POS package: The default physical layer of other devices is SONET, the default physical layer of the router package is SDH, the configuration is different, but can be compatible with each other, will not affect the protocol up, and will not affect data forwarding. However, when the project is implemented, both ends are configured to be consistent. The default physical layer package for the router port is changed to SONET, and the failure remains.

5, view the router port details: the implementation of the command display interface pos 7/0/0 verbose, found that C2 send and receive mismatch, the end of the other routers sent over the value of 207, and the end of the router to send the past 16, so that the port can not be opened.

Third, the fault handling

1, System-view

Enter the system view.

2, Interface pos7/0/0

Enter the corresponding POS interface view.

3, Flag C2 207

Modifying the C2 byte value is consistent with the C2 byte value of the other router POS port on the end.

4, display interface pos 7/0/0 verbose

Check the status of the POS interface, has become up, the problem is resolved.

For 2.5G high speed POS port, it will check the C2 value, the C2 value at both ends will cause the POS port to be unable to open, therefore must modify the C2 value of the high speed POS port to be consistent.