Version Info: Quidway R3640E: VRP (tm) software, Version 1.60 8040-001, Bootrom Version is 4.33.
Description of Fault: RouterC is configured "vofr data 5 call-control 4", but it will not appear when you SHOW RUNNING CONFIGURATION. By the time, the telephone can call from one side to another, and the Serial0 interfaces cannot ping from one side to another. If "vofr data 5 call-control 4" is canceled, then the Serial0 interfaces can ping from one side to another, and the telephone cannot call from one side to another. This moment we capture the debug info while calling from Quidway side. At RouterC side there is no debug info. The result is that there isn't any voice after finishing a dial-up. When it comes to start a call from RouterC side, busy tone appears.
Add fragment configuration on both sides. Configure "Frame-Relay Fragment" in "Map-Class frame?Relay Vofr".
map-class frame-relay vofr
frame-relay voice bandwidth 32000
frame-relay fragment 1600 data-level
In the real test, this problem is solved after finish the change.
Absence of fragment configuration gives cause for this problem. Quidway router runs mult-protocol encapsulation for none-voice data while RouterC runs FRF11 encapsulation. So they cannot intercommunicate.