Interactive Connectivity Establishment (ICE) is a technique used in

computer networking A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections ar ...

to find ways for two computers to talk to each other as directly as possible in

peer-to-peer Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the network. They are said to form a peer-to-peer ...

networking. This is most commonly used for interactive media such as

Voice over Internet Protocol Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet ...

(VoIP),

communications, video, and

instant messaging Instant messaging (IM) technology is a type of online chat allowing real-time text transmission over the Internet or another computer network. Messages are typically transmitted between two or more parties, when each user inputs text and trigge ...

. In such applications, communicating through a central server would be slow and expensive, but direct communication between client applications on the

Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a ''internetworking, network of networks'' that consists ...

is very tricky due to network address translators (NATs), firewalls, and other network barriers. ICE is developed by the

Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and ...

MMUSIC working group and is published as RFC 8445, as of August 2018, and has obsolesced both RFC 5245 and RFC 4091.RFC 4091, ''The Alternative Network Address Types (ANAT) Semantics for the Session Description Protocol (SDP) Grouping Framework'', G. Camarillo, J. Rosenberg (June 2005)

Overview

Network address translation (NAT) became an effective technique in delaying the exhaustion of the available address pool of

Internet Protocol version 4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version de ...

, which is inherently limited to around four billion unique addresses. NAT gateways track outbound requests from a

private network In Internet networking, a private network is a computer network that uses a private address space of IP addresses. These addresses are commonly used for local area networks (LANs) in residential, office, and enterprise environments. Both the IPv4 ...

and maintain the state of each established connection to later direct responses from the peer on the public network to the peer in the private network, which would otherwise not be directly addressable. VoIP, peer-to-peer, and many other applications require address information of communicating peers within the data streams of the connection, rather than only in the Internet Protocol packet headers. For example, the

Session Initiation Protocol The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice, video and messaging applications. SIP is used in Internet telephony, in private IP telep ...

(SIP) communicates the

IP address An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...

of network clients for registration with a location service, so that telephone calls may be routed to registered clients. ICE provides a framework with which a communicating peer may discover and communicate its public IP address so that it can be reached by other peers. Session Traversal Utilities for NAT (STUN) is a standardized protocol for such address discovery including NAT classification. Traversal Using Relays around NAT (TURN) places a third-party server to relay messages between two clients when direct media traffic between peers is not allowed by a firewall.

IETF specifications

RFC 5389
Session Traversal Utilities for NAT (STUN).
RFC 8656
Traversal Using Relays around NAT (TURN): Relay Extensions to STUN.
RFC 6544
TCP Candidates with Interactive Connectivity Establishment (ICE)
RFC 8445
Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal

References

{{Reflist

External links

IETF Journal article on ICE

MMUSIC working group

BEHAVE working group

libnice: GLib ICE library

libjuice: Open source UDP ICE library

coturn: Open source implementation of TURN and STUN Server
Networking standards

Overview

IETF specifications

See also

References

External links