Definitions for "Layer 4"
Keywords:  udp, osi, sctp, transport, netbeui
Transport Layer - Information Exchange - Delivery & Flow
the transmission control layer, provides connection-oriented services that can set up a link between two end-points to monitor data flow and guarantee delivery.
the transport layer, controls the movement of data between systems, defines protocols for structuring messages, and supervises the validity of transmissions by performing error checking.
Establishes a connections and ensures that all data arrives to their destination. Packets inspected at the Layer 4 level are analyzed and forwarding decisions based on their applications.