Summary

Multiplexing is not usually desirable. It forces all media streams to have a single transport, preventing the receiver from prioritizing them according to its needs, and making it difficult to apply error correction. In almost all cases, header compression provides a more appropriate and higher-performance solution.

Nevertheless, in some limited circumstances multiplexing can be useful, primarily when many essentially identical flows are being transported between two points, something that occurs often when voice-over-IP is being used as a backbone "trunk" to replace conventional telephone lines.