This Recommendation is a channel aggregation protocol for multilink operation on circuit-switched networks. It is intended for use in applications where low latency and high efficiency are important considerations, such as H.324 multimedia telephony. Unlike synchronous time-division-multiplexing channel aggregation protocols such as Recommendation H.221 and ISO/IEC 13871 (BONDING), this Recommendation has the ability to operate with a changing number of channels with arbitrary, differing, or continuously varying bit rates (including modems according to Recommendation V.34) as well as fixed-rate channels (such as ISDN B-channels). Unlike packet-oriented channel aggregation protocols such as RFC 1990 (PPP Multilink Protocol), this Recommendation finely distributes payload octets across different channels, simultaneously minimizing latency and overhead.