"Real Time Streaming Protocol 2.0 (RTSP)", Henning Schulzrinne, Anup Rao, Rob Lanphier, Magnus Westerlund, Martin Stiemerling, 5-May-08. ( bytes)

This memorandum defines RTSP version 2.0 which is a revision of the Proposed Standard RTSP version 1.0 which is defined in RFC 2326. The Real Time Streaming Protocol, or RTSP, is an application-level protocol for control over the delivery of data with real-time properties. RTSP provides an extensible framework to enable controlled, on-demand delivery of real-time data, such as audio and video. Sources of data can include both live data feeds and stored clips. This protocol is intended to control multiple data delivery sessions, provide a means for choosing delivery channels such as UDP, multicast UDP and TCP, and provide a means for choosing delivery mechanisms based upon RTP (RFC 3550).

"An Network Address Translator (NAT) Traversal mechanism for media controlled by Real-Time Streaming Protocol (RTSP)", Jeff Goldberg, Magnus Westerlund, Thomas Zeng, 14-Jul-08. ( bytes)

This document defines a solution for Network Address Translation (NAT) traversal for datagram based media streams setup and controlled with Real-time Streaming Protocol version 2 (RTSP 2.0). It uses Interactive Connectivity Establishment (ICE) adapted to use RTSP as a signalling channel, defining the necessary extra RTSP extensions and procedures.

"Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer Protocols", Jonathan Rosenberg, 29-Oct-07. ( bytes)

This document describes a protocol for Network Address Translator (NAT) traversal for UDP-based multimedia sessions established with the offer/answer model. This protocol is called Interactive Connectivity Establishment (ICE). ICE makes use of the Session Traversal Utilities for NAT (STUN) protocol and its extension, Traversal Using Relay NAT (TURN). ICE can be used by any protocol utilizing the offer/answer model, such as the Session Initiation Protocol (SIP).

"An Extension to the Session Description Protocol (SDP) for Media Loopback", Kaynam Hedayat, 4-Aug-08. ( bytes)

The wide deployment of Voice over IP (VoIP), Real-time Text and Video over IP services has introduced new challenges in managing and maintaining voice/real-time Text/video quality, reliability, and overall performance. In particular, media delivery is an area that needs attention. One method of meeting these challenges is monitoring the media delivery performance by looping media back to the transmitter. This is typically referred to as "active monitoring" of services. Media loopback is especially popular in ensuring the quality of transport to the edge of a given VoIP, Real-time Text or Video over IP service. Today in networks that deliver real-time media, short of running 'ping' and 'traceroute' to the edge, service providers are left without the necessary tools to actively monitor, manage, and diagnose quality issues with their service. The extension defined herein adds new SDP media attributes which enables establishment of media sessions where the media is looped back to the transmitter. Such media sessions will serve as monitoring and troubleshooting tools by providing the means for measurement of more advanced VoIP, Real-time Text and Video Over IP performance metrics.

"TCP Candidates with Interactive Connectivity Establishment (ICE)", Jonathan Rosenberg, 14-Jul-08. ( bytes)

Interactive Connectivity Establishment (ICE) defines a mechanism for NAT traversal for multimedia communication protocols based on the offer/answer model of session negotiation. ICE works by providing a set of candidate transport addresses for each media stream, which are then validated with peer-to-peer connectivity checks based on Session Traversal Utilities for NAT (STUN). ICE provides a general framework for describing candidates, but only defines UDP-based transport protocols. This specification extends ICE to TCP-based media, including the ability to offer a mix of TCP and UDP-based candidates for a single stream.

"A Session Description Protocol (SDP) Offer/Answer Mechanism to Enable File Transfer", Miguel Garcia-Martin, Markus Isomaki, Gonzalo Camarillo, Salvatore Loreto, Paul Kyzivat, 20-May-08. ( bytes)

This document provides a mechanism to negotiate the transfer of one or more files between two endpoints by using the Session Description Protocol (SDP) offer/answer model specified in RFC 3264. SDP is extended to describe the attributes of the files to be transferred. The offerer can either describe the files it wants to send, or the files it would like to receive. The answerer can either accept or reject the offer separately for each individual file. The transfer of one or more files is initiated after a successful negotiation. The Message Session Relay Protocol (MSRP) is defined as the default mechanism to actually carry the files between the endpoints. The conventions on how to use MSRP for file transfer are also provided in this document.

"SDP Capability Negotiation", Flemming Andreasen, 11-Jul-08. ( bytes)

The Session Description Protocol (SDP) was intended for describing multimedia sessions for the purposes of session announcement, session invitation, and other forms of multimedia session initiation. SDP was not intended to provide capability indication or capability negotiation, however over the years, SDP has seen widespread adoption and as a result it has been gradually extended to provide limited support for these, notably in the form of the offer/answer model defined in RFC 3264. SDP does not define how to negotiate one or more alternative transport protocols (e.g. RTP profiles) or attributes. This makes it difficult to deploy new RTP profiles such as secure RTP or RTP with RTCP-based feedback, negotiate use of different security keying mechanisms, etc. It also presents problems for some forms of media negotiation. The purpose of this document is to address these shortcomings by extending SDP with capability negotiation parameters and associated offer/answer procedures to use those parameters in a backwards compatible manner. The document defines a general SDP Capability Negotiation framework. It also specifies how to provide attributes and transport protocols as capabilities and negotiate them using the framework. Extensions for other types of capabilities (e.g. media types and media formats) may be provided in other documents.

"SDP media capabilities Negotiation", Robert Gilman, Roni Even, Flemming Andreasen, 14-Jul-08. ( bytes)

Session Description Protocol (SDP) capability negotiation provides a general framework for indicating and negotiating capabilities in SDP. The base framework defines only capabilities for negotiating transport protocols and attributes. In this document, we extend the framework by defining media capabilities that can be used to negotiate media types and their associated parameters. This extension is designed to map easily to existing and future SDP media attributes.

"The evaluation of different NAT traversal Techniques for media controlled by Real-time Streaming Protocol (RTSP)", Magnus Westerlund, Thomas Zeng, 11-Jul-08. ( bytes)

This document describes several NAT traversal techniques that could be used by RTSP. Each technique includes a description on how it would be used, the security implications of using it and any other deployment considerations it has. There are also disussions on how NAT traversal techniques relates to firewalls and how each technique can be applied in different use cases. These findings where used when selecting the NAT traversal for RTSP solution to standardize in the MMUSIC WG.

"Quality of Service (QoS) Mechanism Selection in the Session Description Protocol (SDP)", James Polk, Subha Dhesikan, Gonzalo Camarillo, 24-Jan-08. ( bytes)

The offer/answer model for SDP assumes that endpoints establish, somehow, the QoS required for the media streams they establish. Endpoints in closed environments typically agree out of band (e.g., using configuration information) which QoS mechanism to use. However, on the Internet, there is more than one QoS service available. Consequently, there is a need for a mechanism to negotiate which QoS mechanism to use for a particular media stream. This document defines such a mechanism.

"Source-Specific Media Attributes in the Session Description Protocol (SDP)", Jonathan Lennox, Joerg Ott, Thomas Schierl, 25-Feb-08. ( bytes)

The Session Description Protocol provides mechanisms to describe attributes of multimedia sessions and of individual media streams (e.g., Real-time Transport Protocol (RTP) sessions) within a multimedia session, but does not provide any mechanism to describe individual media sources within a media stream. This document defines a mechanism to describe RTP media sources, identified by their Synchronization Source Identifiers (SSRCs), in SDP, associate attributes with these sources, and express relationships among sources. It also defines several source-level attributes which can be used to describe properties of media sources.

"Signaling media decoding dependency in Session Description Protocol (SDP)", Thomas Schierl, Stephan Wenger, 23-May-08. ( bytes)

This memo defines semantics that allow for signaling the decoding dependency of different media descriptions with the same media type in the Session Description Protocol (SDP). This is required, for example, if media data is separated and transported in different network streamsas a result of the use of a layered or multiple descriptive media coding process. A new grouping type "DDP" -- decoding dependency -- is defined, to be used in conjunction with RFC 3388 entitled "Grouping of Media Lines in the Session Description Protocol". In addition, an attribute is specified describing the relationship of the media streams in a "DDP" group indicated by media identification attribute(s) and media format description(s).

"SDP: Session Description Protocol", Mark Handley, 9-Jun-08. ( bytes)

This memo defines the Session Description Protocol (SDP). SDP is intended for describing multimedia sessions for the purposes of session announcement, session invitation, and other forms of multimedia session initiation.

"Analysis of Middlebox Interactions for Signaling Protocol Communication along the Media Path", Brian Stucker, Hannes Tschofenig, 14-Jul-08. ( bytes)

Middleboxes are defined as any intermediary box performing functions apart from normal, standard functions of an IP router on the data path between a source host and destination host. Two such functions are network address translation and firewalling. When Application Layer Gateways, such as SIP entities, interact with NATs and firewalls, as described in the MIDCOM architecture, then problems may occur in the transport of media traffic when signaling protocol interaction takes place along the media path, as it is the case for recent key exchange proposals (such as DTLS-SRTP). This document highlights problems that may arise. Unfortunately, it is difficult for the end points to detect or predict problematic behavior and to determine whether the media path is reliably available for packet exchange. This document aims to summarize the various sources and effects of NAT and firewall control, the reasons that they exist, and possible means of improving their behavior to allow protocols that rely upon signaling along the media path to operate effectively.

"The SDP (Session Description Protocol) Grouping Framework", Gonzalo Camarillo, 6-Jul-08. ( bytes)

In this specification, we define a framework to group "m" lines in SDP (Session Description Protocol) for different purposes. This framework uses the "group" and "mid" SDP attributes, both of which are defined in this specification. Additionally, we specify how to use the framework for two different purposes: for lip synchronization and for receiving a media flow consisting of several media streams on different transport addresses.

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