SIP/RTSP convergence draft-whitehead-mmusic-sip-for-streaming-media-05 Authors: Jan Lindquist Marie-Jose Montpetit Xavier Marjou Sam Ganesan

Presentation Outline Use Cases + possible solutions Server Control of Streaming Session Remote Access to Private/Firewalled Video Content VOD services that requires resource or QOS-guarantees Intelligent selectionof media encoding Voice/video mailbox Motion Detection Considerations for session control protocol

Use-Case 1: Server Control of Streaming Session (1/2) Need: The server must be able to indicate the end of session to the client (e.g. if the server needs to be stopped for administrative purpose). Possible solutions: Use a SIP BYE message, or, add a new RTSP message (eg draft-stiemerling-rtsp-announce-01)

Use-Case 1: Server Control of Streaming Session (2/2) SIP Proxy/Reg(B) Media Relay Agent A NAT(B) Agent B Public side Private side SIP BYE SIP BYE SIP 200 OK SIP 200 OK

Use-Case 2: Remote Access to Private/Firewalled Video Content (1/3) Need: to reach the RTSP server located behind a residential NAT Possible solutions: A SIP/RTSP-like solution helps, as shown on next slide, or, Add an RTSP REGISTER message, and extends RTSP proxy.

Use-Case 2: Remote Access to Private/Firewalled Video Content (2/3) SIP Proxy/Reg(B) Media Relay Agent A NAT(B) Agent B Public side Private side SIP REGISTER (with outbound) SIP INVITE m=application 9 TCP/RTSP-like c=IN IP4 IP-agent-a a=setup:active SIP INVITE m=application 48000 TCP/RTSP-like c=IN IP4 IP-media-relay a=setup:passive TCP SYN TCP SYN RTSP-like PLAY RTP Media RTP Media

Use-Case 2: Remote Access to Private/Firewalled Video Content (3/3) Note: In the previous slide, an SBC is used for shorter call-flows, but similar call-flows can be established with ICE instead of SBC so that media flows go through NATs. A SIP/RTSP solution both allows NAT traversal and authentication of user A.

Use-Case 3: Intelligent selection of media encoding (1/1) Need: perform a negotiation between clients and server on media formats, media codecs and bandwidth available. Possible Solutions The SDP offer/answer can be re-used Offer/answer enable a media formats negotiation (add/remove streams for example for SVC) Offer/answer enables the "client" to indicate its media preferences Add offer/answer mechanism to RTSP

Use-Case 4: VOD services that requires resource or QOS-guarantees (1/2) Need: establish an end to end session setup and management in order to control the network resources and QoS Possible Solutions Use SIP to setup session and use IMS architecture to ensure available resources and QoS.

Use-Case 4: VOD services that requires resource or QOS-guarantees (2/2) SIP Proxy/Reg(B) Media Relay Agent A Agent B Public side SIP INVITE (SDP offer) SIP INVITE (SDP offer) SIP 200 OK (SDP answer) SIP 200 OK (SDP answer) RTSP-like PLAY RTP Media RTP Media

Use-Case 5: Voice/video mailbox (1/1) Need: establish a session to a mailbox server and perform playback control of the voice/video messages with the possibility to save or delete messages. The mailbox can be in the home or in the network. Possible Solutions Reuse SIP registration to be able to access mailbox in the home and add some extensions to be able to control individual voice/video messages.

Use-Case 6: Motion Detection (1/4) Need: after being informed of motion detection connect to a home monitoring equipment and see live video feed plus be able to rewind the video feed. Possible Solutions Reuse the SIP registration and get notified of motion detected using SIP message. Then perform SIP invite to establish a connection to the video feed. A SMTP or SIP message with an RTSP link does not always work, as shown on next slide. or, a SIP with offer/answer solution

Use-Case 6 : Motion Detection (2/4) A MESSAGE with link does not suffice because of NATs SIP Proxy/Reg(B) Media Relay Agent A NAT(B) Agent B Public side Private side Waiting For Motion events SMTP or SIP MESSAGE rtsp://IP-Agent-B/stream SMTP or SIP MESSAGE rtsp://IP-Agent-B/stream, or rtsp://IP-Agent-B-corrected/stream Event arises TCP SYN for RTSP

Use-Case 6 : Motion Detection (3/4) SIP Proxy/Reg(B) Media Relay Agent A NAT(B) Agent B Public side Private side Waiting Motion events SIP INVITE m=application 48000 TCP/RTSP-like c=IN IP4 IP-media-relay a=setup:active SIP INVITE m=application 9 TCP/RTSP-like c=IN IP4 IP-agent-a a=setup:passive Event arises TCP SYN TCP SYN RTSP-like PLAY RTP Media RTP Media

Use-Case 6 : Motion Detection (4/4) Note: Again an SBC is used for shorter call-flows, but similar call-flows can be drawn with ICE instead of SBC in order to that media flows go through NATs.

Considerations for session control protocol The session protocol shall allow server initiated control of streaming sessions such as server-initiated session terminations. RTSP TEARDOWNs are from client to server only. RTSP protocol assumes a media server is located in the network and not in the home. The session protocol shall be possible to establish a relationship that allows for control of media resoruces in both the home and network. The session protocol shall be able to handle NAT and not affect the call flows being defined. If assuming SIP for session protocol there is a well accepted architecture defined called IMS, IP Multimedia Solution, which is accepted by a number of standard organizations like 3GPP, ETSI TISPAN, ATIS, etc. There is a number of services have been defined using the architecture like telephony, push to talk, presence, messaging, chat and IPTV. In conjunction with IMS there is a resource and admition control architecture called RACS defined in ETSI TISPAN which helps ensure QoS for services defined over IMS and addresses reuse of network resources. What is of special interest is bandwidth reservation is addressed for unicast and multicast media streams as well as handling of multicast addresses used for IPTV. IMS also provides additional authentication mechanisms which allow alternatives for HTTP Digest like the Authentication and Key Agreement mechanism (AKA).

Requirements REQ-1 The media control protocol must support commands such as play, pause, rewind, forward, fast rewind, fast forward, slow rewind, and slow forward. REQ-2 It must be possible to negotiate the media control protocol of a media stream. REQ-3 If the media control protocol does not apply to all media streams of a given session, it must be possible to indicate the specific media streams that are under the scope of the trick-play control protocol. REQ-4 The media control protocol must allow for asynchronous media event notifications (e.g.: end-of-stream)". REQ-5 The protocol SHOULD work over TCP. REQ-6 The media stream, or media control server, to be controlled by the client may be located in the network or in the home network. REQ-7 The media control protocol shall consider additional commands not available in RTSP to control the media in the server. Examples of such commands are deletion or saving of voice messages.