5tuple

A 5-tuple is an ordered collection of five elements. In mathematics, a k-tuple is a sequence of length k, so a 5-tuple is an element of the Cartesian product A1 × A2 × A3 × A4 × A5. When the five components come from the same set, a 5-tuple can be viewed as a point in five-dimensional space, often written as (a1, a2, a3, a4, a5).

In computer science and related fields, the concept serves as a generic data container or as the input for functions. A fixed 5-tuple represents a data record with five attributes; more generally, it is one instance in Ax × By × Cz × Dw × Ev for sets A, B, C, D, E. For any five elements from possibly different domains, the 5-tuple uniquely retains their order.

In computer networking, the term 5-tuple commonly denotes the five fields that identify a network flow: source IP address, destination IP address, protocol, source port, and destination port. This descriptor is used by routers, firewalls, and intrusion detection systems to classify and manage traffic. Some deployments add extra qualifiers, such as IP version, VLAN, or transport flags, to distinguish flows that share these five fields or to handle network address translation.

Related concepts include n-tuple, Cartesian product, and tuple.