Symptom
NE28 and NE29 are unreachable to the T2000 after the primary GNE is switched to the secondary GNE (NE111). That is, the secondary GNE becomes unavailable.
Cause analysis
The maximum number of route hops of NE28 or NE29 is set to 20. Actually, the number of route hops between NE28 (or NE29) and the GNE is greater than 20. As a result, a standby route is not available between NE28 and NE29 and communication between the two NEs is interrupted.
Procedure
- Determine that the SCC boards and NE software of the two NEs function normally and that the communication parameters are set correctly, considering that NE28 and NE29 are reachable to the T2000 when they are managed by the primary GNE.
- Query the maximum number of route hops of each NE and find that the number is 20, which is smaller than the actual number of route hops. This leads to a failure to search for a standby route.
- Set the maximum number of route hops to the default value 64. The problem is resolved.
Reference Information
The common causes of the fault are as follows:
- The communication parameters, for example, NE ID, subnet mask, and FEC mode, are set incorrectly.
- The SCC board of the NE is reset repeatedly.
- The network is unstable because the number of connected NEs in auto ECC extension mode exceeds the permitted value.
