idle) Disconnect causes Q.2931 Q.2931 is a modified and extended variant of Q.931 for use on "B-ISDN" or ATM networks. Q.2931 fulfils a purpose within BISDN similar to that of Q.931 in ISDN. Whilst ISDN allocates bandwidth in fixed 64k increments, B-ISDN/ATM incorporates an elaborate traffic management scheme, allowing precise specification of virtual circuit traffic parameters such as peak and mean bandwidth, jitter, cell loss ratio and so on. In order that ATM switches can manage bandwidth allocation in the network, encodings to express these parameters were added in Q.2931. Unlike Q.931, although Q.2931 was implemented by many switch manufacturers, it was never widely deployed. References Integrated Services Digital Network ITU-T recommendations ITU-T Q Series Recommendations