FragmentHeader

FragmentHeader is a general term used in computing to denote the metadata that accompanies a fragment of a larger data unit. Depending on context, a fragment header may be part of a network protocol, a media streaming system, or a data processing framework. Its primary function is to enable correct reassembly, ordering, and validation of fragments by conveying identity, position, size, and timing information.

In network protocols that support fragmentation, the fragment header typically includes an identification field, a fragment offset, and a flag indicating whether more fragments follow. These fields allow a recipient to group pieces that belong to the same original payload and reconstruct it even when fragments arrive out of order. Some protocols also carry length and integrity information within the header.

In software libraries and pipelines, a FragmentHeader is commonly a small structure or class that stores fragment_id, fragment_index, total_fragments, fragment_type, a timestamp, and payload_length. It is usually serialized with the fragment payload and used by the reassembly logic to determine order and completeness, detect duplicates, and manage timeouts. Implementations may support immutability, efficient comparison, and zero-copy techniques.

Design considerations include minimizing header overhead, ensuring deterministic reassembly order, handling missing or duplicate fragments gracefully, and providing clear error reporting. FragmentHeader concepts appear in networking, multimedia streaming, data synchronization, and distributed systems.

See also: Fragment, Header, Packet fragmentation.