A 1978 standardization of virtual circuits by the CCITT imposes per-connection flow controls at all user-to-network and network-to-network interfaces.
This permits participation in congestion control and reduces the likelihood of packet loss in a heavily loaded network.
[1][2] Some circuit protocols provide reliable communication service through the use of data retransmissions invoked by error detection and automatic repeat request (ARQ).
[3] In the early 1970s, virtual call capability was developed by British Telecom for EPSS (building on the work of Donald Davies at the National Physical Laboratory).
The concept was enhanced by Rémi Després as virtual circuits for the RCP experimental network of the French PTT.