Little info about Multiplexers/De-Multiplexers in the comm

[Aldec_forever]

Does anyone have any kind of information about Multiplexers/De-Multiplexers techniques in the communication standards? I ask this question because there are lots of additional bits that are added to the payload/user data for many reasons. The whole package is send the user streamingly and then demultiplexed at the terminal side. The tedious job is converting the multi small frames to a streaming format without any hole inside them. This process needs tricky methods like using delay lines, aligning buffers and etc. Has any one faced with this kinds of problems?