| Abbreviation | Definition |
|---|---|
| UDLC | UNIVAC Data Link Control |
| UDLD | UniDirectional Link Detection |
| UDLP | Universal Dynamic Link Protocol |
| UDN | Unique Device Name |
| UDN | Univision Deportes Network |
| UDN | Unreal Developer Network |
| UDP | Undefined Destination Packet |
| UDP | Universal Data Port |
| UDP | User Data Protocol |
| UDP | User Datagram Protocol |
| UDRP | Uniform domain-name Dispute-Resolution Policy |
| UDS | Universal Datacom System |
| UDSP | Utilizing Digital Signal Processor |
| UDT | Uniform Data Transfer |
| UDX | Unattended Data Xchange |
| UEAN | User Environment Area Network |
| UFB | Ultra-Fast Broadband |
| UFB | Universal Fall Back |
| UFBS | Universal Fall Back Switch |
| UFN | User Friendly Naming |