Failed to ping the other side with X.25 on both sides being up
Symptom
Despite X.25 being up on both sides, the other side cannot be pinged.
Analysis
The maximum length of frames set at one side is too small.
Solution
Enable the debugging on both sides. If one side discards incoming frames without delivering them to the upper layer, it indicates the maximum length of frames set for this side is too small. Change the frame length configuration of this side.