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SIP/ SIMPLE : A control architecture for the wiredand wireless Internet ?Arup AcharyaNetwork Server Systems SoftwareAdvanced Networking Services (On-Demand Innovation Services)IBM T J Watson Research Centersip:arup@research.ibm.com
What is SIP (Session Initiation Protocol) ?(Overview)Session Initiation ProtocolSIP server SIPsignalingAn Internet signaling protocol for setting up multimedia sessions SIP serverSIP serverMobility support – call control in 3G networksoTerminal / service mobilityRTP/UDPvoice packetsV Uses (overlay) control network of SIP servers independent of media type (voice, video)Media Path (RTP/UDP) decoupled from signalingDynamic negotiation of device capabilities, media typeMessage routing is application specifico DNS-basedname@domain addressing VDynamic resolution of SIP URIs to device(s)o Location-basedDNS enhancements for SIP service records & ENUMVOIPTelephony & Voice MailUnified MessagingFindFind-MeMe-FollowFollow-MeCall CenterMessage syntax similar to HTTPSIMPLE : SIP extensions to support Presence and IM Pub/Sub mechanism IM carried as signaling message payload oIP TVCollaborationReal time mediaRealtime mediaprotocols(RTP)protocols(RTP)And codecsAnd codecsPushToTalkIMS (3G)HTTPHTTPXMLXMLRegistrationSubscription & SessionNotifications NegotiationPush-to-talk on cell-phonesInternet Protocol (IP)SIP : an end-to-end control protocol not so far present in theInternet ? 2NetworkIntegrationwithWebWeb-portalsClient DesktopDevicesServersSIP/SIMPLESIP/SIMPLE
IBM Global ServicesWidespread adoption of SIP/SIMPLE Enterprise Software vendorssikAT&T, MCI, Earthlink, [Vonage, Packet8, .]roTime Warner, Comcastwt ” vendors “Networkinge(Hosted) Covad, Verizon, n Nortel, Nokia, Lucent, .Cisco,lortWireless providersn Emerging? InfrastructureoSprint/Nextel, Verizon Wireless,.n/c tiovendorsy[Push-to-talk]a ucSonus, NexTone, Antepo,.lr3G (IMS)e strOpen Source : SIPFoundryvoneoWeb portals : Yahoo, MSN, dAOL Peer-to-peer SIPi rcweEarthlink SIPsharetdeApplication ServiceProviders:WebexnSOSIMPLEnureSkype (proprietary)tnCorporate IEnterprise IT/networks Gaming ConsolesAn Wireline providers [consumer/ business]--Microsoft,IBM, Oracle, BEA, .- -- -- Sony Playstation announcedsupport for VoIP-3 Copyright IBM Corporation 2005
Impact of SIP in the enterprise IT/ network infrastructure Enterprise communication now runs on a common infrastructure of servers and data networkSIP servers adjunct to web servers / directoriesIntegrate web & SIP applications on (a) client desktops and (b) servers Web browsers can be expected to recognise SIP URIsCommunication applications are desktop based : voice/video, presence, instant messagingConferencingServerProxyIM atewayEnterprisedirectorySIPHTTPSIP InfrastructureIP-PSTNMedia gwEthernet / 802.11IP Network (routers, switches.)4
Demo scenario : Web page with ‘clickable’ SIP URIsClick hereto call me(SIPrecognised asa first-classprotocol likeHTTP or mailtowithout anychange tobrowser code)5
Impact of SIP : server-based networkingTelecom morphs to ITCircuit-SwitchedMONOLITHICServices &ApplicationsCall Controlintegrated withswitchinghardwareVoiceTransportSIP-based IPCommunicationsServices, Applications & Features(integration with businessprocesses)APIsSession Control : SIP serversAPIsCommon IP Network for bothvoice and data Server platforms (instead of dedicated switching PSTN hardware) Control (session, call) implemented as server application software6
Role of SIP in 3rd Generation mobile networks : IMSIP Multimedia subsystem (IMS) in 3GPP is based on SIPCall/session control and roaming via SIPSIP client on cell-phones : SMS replaced by SIP-based IMCall SessionControlFunction(CSCF)SIP enableddevicesPresenceSIPPush-to-talkIP Multimedia CoreIMGPRS/EDGE/WCDMAGGSNIP transportAny SIP ASService enablers/applications7ApplicationServers
SIP Messages : Header Body SIP Headers Message Body Captures best of both worlds?– Efficiency of IP headers– Flexibility of Application-layermessages8UDP HeaderINVITE sip:Gordon@CA.IBM.COM SIP/2.0Via: SIP/2.0/UDP sip-proxy.watson.ibm.comFrom: Arup Acharya sip:arup@research.ibm.com To: Gordon Kerr sip:Gordon@CA.IBM.COM Call-ID: c2943000-e0563-2a1ce-2e323931@9.2.91.243CSeq: 1 INVITEExpires: 180User-Agent: Cisco IP Phone/ Rev. 1/ SIP enabledAccept: application/sdpContact: sip:arup@9.2.91.243:5060Content-Type: application/sdpContent-Length : 124v 1o V C IN IP4 9.2.91.243t m video 4004 RTP/AVP 13 26a rtpmap:14 MPA/90000SIP BODY– Could be XML / SDP / text/.(e.g Presence Subscriptions)– Not (required to be)interpreted hop-by-hopIP HeaderSIP HEADER– Used for routing at SIPservers– Could be modified hop-by-hop– Routing is application-specific– Ok not to recognize a (new)field
Possible impact on Internet-based services / architecture A new de-facto control layerSIPbased on SIPSIP server(control overlay)Media Server-based networking “Interesting” services are derivedfrom this overlay networkPSTNMedia Sessions(voice, video,.)InstantmessagingPresenceEvent Notification(pub/ ControlSIPSIP-based Primitives / Base PresenceServerIntegrationwithDNS/ ENUMSIPSIP-based Convergence layerTCP/IP Network : Connectivity / Routing / Transport9SessionBorderControl(firewalls)
Ongoing Research Project : Scaling SIP serversSIP is multi-faceted; thus, potentially multiple server performance bottlenecks Presence Session Setup (voice/ video) Rate of subscription / notification requestsRegistrationserver Updates in presence information, including nonSIP sourcesRedirect/ setupSIP proxySUBSCRIBENOTIFYPresenceInformationRTP/UDP packets(media) -SIP registrar-Network login(e.g. 3G)- .Collaboration, e.g. conferencing erverInstant Messaging Number of messages Size of messagesMediamixerInstantMessageIM ServerRTP/UDPpackets (media)10Joint work with E. Nahum, J.M. Tracey, Z.Y. Shae, X. Wang (IBM Research)
SIP on Wearable Devices (Linux WatchPad) Linux WatchPad as a wearable control device Interface always visible/ easily accessibleReceive phone calls on watch and decide how to respondMove an ongoing call from a PSTN phone to cell phoneReceive IMs with yes/no responsesSubscription notifications : display as icons Prototype completed, patent filed11Joint work with Wearable Computing Group (Stefan Berger, Chandra Narayanaswami)
Conclusions Adoption of SIP across enterprise, service provider and mobile providerseffectively creating an Internet-wide overlay control network Servers and software have a transformational role to play Shift from router-based networking to server-based “networking” Is this the next step in the architectural evolution of the Internet ?THANK YOU!More information:Contact : Arup Acharya, IBM TJ Watson Research Ctrarup@us.ibm.com / 1 914 784 er details on SIP work in IBM /custom2.html12
Research SIP Pilot new components (application integration,conferencing service)SIP ConferenceManagerApplicationServer (IM,email, areSIPcontrolRTP/UDPVoice packets(multimulti-partyconnection)connection)SIP Proxy ServerSIPSIPCisco 3640SIP gatewayRTP/UDPVoice packets(point(point-pointconnection)Client LaptopApplicationSiemensPBXPSTNtransferSIPSIP App serviceintegration13SIP phonePSTN phonePOTS phone
SIP client on cell-phones : SMS replaced by SIP-based IM. 8 SIP Messages : Header Body SIP Headers – Used for routing at SIP servers – Could be modified hop-by-hop – Routing is application-specific – Ok not to recognize
