Segmentationreassembly

Segmentationreassembly is the process by which data is divided into smaller units for transport, storage, or processing and then reconstructed into the original data unit at the destination.

In networking, segmentationreassembly typically refers to fragmentation and reassembly of packets. When a packet exceeds the path MTU, intermediate devices fragment it; fragments include offset and identification, and the destination reassembles the original datagram if all fragments arrive. Reassembly fails if fragments are lost or arrive late, discarding the datagram. Techniques such as Path MTU Discovery aim to avoid fragmentation, while some devices filter or mishandle fragmented traffic due to security concerns.

In reliable transport and application protocols, segmentation breaks a data stream into manageable units with sequence numbers. The receiver reassembles segments in order, enforcing data integrity and flow control, and handling retransmissions. This form of segmentationreassembly underpins TCP and many application protocols that buffer data.

Beyond networks, segmentationreassembly appears in multimedia streaming and distributed storage. Large payloads may be split to fit transport limits or decoding constraints, then reassembled for playback. In erasure-coded or distributed storage systems, data is split into chunks across nodes and later reconstructed.

Key considerations include security risks, buffering requirements, and performance trade-offs. Minimizing fragmentation and implementing robust reassembly timeouts are common design goals.