Frame relay communication device, frame relay exchange, frame relay communication system and PVC state confirmation procedure control method

摘要

A frame relay communication apparatus (10) is a second state inquiry message se-f (FF) for querying the normality of a first data link PVC 1 (second data link PVC 2) between a communication relay frame relay communication device connected via a frame relay network The Le state display is transmitted at least twice to the frame relay network F1. The frame relay communication apparatus 10 receives a second response message s-f corresponding to the second state inquiry message se-f transmitted from the frame relay network State is recognized. Therefore, when the state of the first data link PVC 1. Sub.1 changes after the first second response message s-f is transmitted, the frame relay communication apparatus 10 recognizes the state of the first data link PVC 1. Sub.1 by the second second response message s-f.