Full form: User Datagram Protocol
Also known as: User Datagram Protocol
Quick Definition
A Layer 4 connectionless protocol that prioritises speed over reliability.
UDP is a Layer 4 (Transport layer) protocol that sends datagrams without establishing a connection, guaranteeing delivery, or ordering segments. It has lower overhead than TCP because it skips the handshake and acknowledgement mechanisms. UDP is preferred where speed and low latency matter more than reliability, such as VoIP, streaming video, DNS lookups, SNMP, and DHCP.
Both DNS (port 53) and DHCP (ports 67/68) use UDP, not TCP. TFTP also uses UDP (port 69). These are common CCNA exam question targets.
A Layer 4 connection-oriented protocol that guarantees reliable, ordered delivery.
A protocol that automatically assigns IP addresses and network parameters to clients.
A hierarchical system that translates human-readable hostnames into IP addresses.
A protocol used to monitor and manage network devices via a Network Management Station.
A simple UDP-based file transfer protocol used to backup and restore Cisco IOS images and configs.
UDP is a Layer 4 (Transport layer) protocol that sends datagrams without establishing a connection, guaranteeing delivery, or ordering segments. It has lower overhead than TCP because it skips the handshake and acknowledgement mechanisms. UDP is preferred where speed and low latency matter more than reliability, such as VoIP, streaming video, DNS lookups, SNMP, and DHCP.
Both DNS (port 53) and DHCP (ports 67/68) use UDP, not TCP. TFTP also uses UDP (port 69). These are common CCNA exam question targets.
UDP falls under the Network Fundamentals domain of the 200-301 exam. Understanding it in context with related terms like tcp and dhcp is essential for answering scenario-based questions correctly.