Which protocol is associated with IP protocol number 17?

The protocol associated with IP protocol number 17 is UDP (User Datagram Protocol). This is defined in the Internet Assigned Numbers Authority (IANA) protocol number assignments. UDP is a connectionless protocol that operates on top of the Internet Protocol (IP) and is used for applications that require fast, efficient transmission of data without needing to establish a reliable connection. Examples of UDP-based applications include DNS (Domain Name System) and streaming media, where speed is more critical than the reliability of delivery.

In contrast, TCP (Transmission Control Protocol), which uses protocol number 6, is a connection-oriented protocol that ensures reliable data transmission, making it suitable for applications like web browsing and file transfers. ICMP (Internet Control Message Protocol) has a protocol number of 1 and is used for sending error messages and operational information, and OSPF (Open Shortest Path First) is a routing protocol that does not have an IP protocol number as it operates at the network layer and utilizes different mechanisms for information exchange.