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SIP/RTSP convergencedraft-whitehead-mmusic-sip-for-streaming-media-05

Authors:Jan LindquistMarie-Jose MontpetitXavier MarjouSam Ganesan

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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

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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)

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Use-Case 1:

Server Control of Streaming Session (2/2)

Agent A NAT(B) Agent BSIP

Proxy/Reg(B)

SIP BYESIP BYE

Media

Relay

Private sidePublic side

SIP 200 OK SIP 200 OK

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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.

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Use-Case 2:Remote Access to Private/Firewalled Video Content (2/3)

Agent A NAT(B) Agent BSIP

Proxy/Reg(B)

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-likec=IN IP4 IP-media-relay a=setup:passive

Media

Relay

TCP SYNTCP SYN

RTSP-like PLAY

RTP MediaRTP Media

Private sidePublic side

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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.

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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

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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.

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Use-Case 4: VOD services that requires resource or QOS-guarantees (2/2)

Agent A Agent BSIP

Proxy/Reg(B)

SIP INVITE (SDP offer)SIP INVITE (SDP offer)

Media

Relay

RTSP-like PLAY

RTP MediaRTP Media

Public side

SIP 200 OK (SDP answer)SIP 200 OK (SDP answer)

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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.

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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

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Use-Case 6 : Motion Detection (2/4)

Agent A NAT(B) Agent BSIP

Proxy/Reg(B)

SMTP or SIP MESSAGE

rtsp://IP-Agent-B/stream, orrtsp://IP-Agent-B-corrected/stream

SMTP or SIP MESSAGE

rtsp://IP-Agent-B/stream

Media

Relay

TCP SYN for RTSP

Private sidePublic side

Waiting For Motion events

Event arises

• A MESSAGE with link does not suffice because of NATs

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Use-Case 6 : Motion Detection (3/4)

Agent A NAT(B) Agent BSIP

Proxy/Reg(B)

SIP INVITE

m=application 9 TCP/RTSP-like c=IN IP4 IP-agent-a a=setup:passive

SIP INVITE

m=application 48000 TCP/RTSP-likec=IN IP4 IP-media-relay a=setup:active

Media

Relay

TCP SYNTCP SYN

RTSP-like PLAY

RTP MediaRTP Media

Private sidePublic side

Waiting Motion events

Event arises

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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.

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Considerations for session control protocol1. 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.

2. 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.

3. The session protocol shall be able to handle NAT and not affect the call flows being defined.

4. 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.

5. 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.

6. IMS also provides additional authentication mechanisms which allow alternatives for HTTP Digest like the Authentication and Key Agreement mechanism (AKA).