RFC 7065 - 1. Introduction

1. Introduction

This document specifies the syntax and semantics of the Uniform Resource Identifier (URI) scheme for the Traversal Using Relays around NAT (TURN) protocol.

The TURN protocol is a specification allowing hosts behind NAT to control the operation of a relay server. The relay server allows hosts to exchange packets with its peers. The peers themselves may also be behind NATs. RFC 5766 [RFC5766] defines the specifics of the TURN protocol.

The "turn" and "turns" URI schemes are used to designate a TURN server (also known as a relay) on Internet hosts accessible using the TURN protocol. With the advent of standards such as WebRTC [WEBRTC], we anticipate a plethora of endpoints and web applications to be able to identify and communicate with such a TURN server to carry out the TURN protocol. This implies that endpoints and/or applications must be provisioned with the appropriate configuration to identify the TURN server. Having an inconsistent syntax adds ambiguity and can result in non-interoperable solutions and implementation limitations. The "turn" and "turns" URI schemes help alleviate most of these issues by providing a consistent way to describe, configure, and exchange the information identifying a TURN server.

[RFC5928] defines a resolution mechanism to convert a secure flag, a host name or IP address, a potentially empty port, and a potentially empty transport to a list of IP address, port, and TURN transport tuples.

To simplify the provisioning of TURN clients, this document defines the "turn" and "turns" URI schemes that can carry the four components needed for the resolution mechanism.