VoIP Signaling Protocols Framework N. Rajagopal, MindTree Consulting Pvt Ltd

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 Agenda H.323 MGCP/MeGaCo SIP Deployment scenarios in India Summary ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 H.323 Family of protocols ITU Recommendation V1 approved in 1996, V2 in 1998 Defines multimedia applications over packet based networks Originally developed for voice over LANs Widely deployed ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 H.323 Protocol Stack Peer to Peer nature Family of protocols H.225.0: Call signaling H.225.0 RAS H.245 Conference control RTP/RTCP for transport ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 H.323 Components H.323 MCU H.323 Gatekeeper H.323 Terminal LAN H.323 Gateway PSTN ISDN ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 MGCP Media Gateway Control Protocol Based on master –slave architecture “Call agent” – master “Media gateways” – slave Call agent Setups the calls between end points Media gateways Does IP <-> voice media conversion ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 MGCP Protocol stack RFC 2705 Supports “packages” for different applications DTMF, Trunking IVR, Media Server Uses RTP/RTCP for transport Designed for TCP/IP network Text based messages ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

MGCP Network architecture Call Agent Trunking Gateway IP Network IP Network Trunking Gateway Media Gateway Analog Phones ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 MeGaCo Media Gateway Control Protocol Similar to MGCP More complete Flexibility Extensibility Video support Other transport support ATM ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 SIP Session Initiation Protocol (RFC 2543) Management of multimedia sessions Simple, easy protocol 6 messages to get started Uses RTP for media transport Lots of extensions being proposed Standards evolving Possibility of different services Good potential ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

Comparison between Protocols H.323 MGCP/MeGaCo SIP Purpose Multimedia conferencing; Media gateway control Multimedia conferencing Defined by ITU-T IETF Complexity High (multiple protocols: H.225.0 for signaling, H.225 RAS for GK communication, H.245 for call signaling Moderate Simple (6 messages) Endpoint requirements Intelligent Dumb (POTS will do) PSTN connectivity thru Gateway Media Gateway + Signaling Gateway Outbound proxy ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

Comparison between protocols (cont’d) Number of messages H.323/100+ MGCP/~10 SIP/6 Type of messages Binary Text, readable Media description   SDP Voice Transport RTP Signaling transport TCP UDP UDP/TCP Capabilities H.245 for capabilities exchange to support different transfers Limited SDP; limited abilities Extensibility Difficult Easy Remarks Legacy; Need to support for today’s networks May get relegated to trunking after widespread deployment of SIP Likely Signaling protocol of future! ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

Deployment Scenarios in India H.323 LAN Telephony Inter office PSTN toll bypass Remote office connectivity IP Phones ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

Deployment scenarios in India Office 1 Office 2 IP Phone Leased lines IP Network PC Office 3 PC IP Phone PC ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

Deployment scenarios in India SIP Experimental Promises are high Windows XP support – ubiquitous Likely areas of usage Desktops LAN telephony ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

Deployment scenarios in India SIP Services Presence, messaging Integrated services Productivity improvement ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

Deployment scenarios in India SIP Call Centers PC Phone PC with SIP Call Desk Call Desk PC Phone Cabling Network Cabling Network Cabling ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

Deployment scenarios in India MGCP Cable telephony MTU telephony Set Top Box (Media Gateway) TV Headend (CallAgent) Ethernet POTS Home Cable PSTN ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 Summary H.323, SIP, MGCP all have their space in VoIP space Likely coexistence “Softswitch architecture” to control the elements in VoIP network “Services” will be key differentiator for customer CLECs/new generation service providers likely to go for softswitch based solution ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019

ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 References http://www.softswitch.org http://www.ietf.org http://www.sipcenter.org http://www.cs.columbia.edu/sip ITU-T and ITU-D Workshop - Bangalore (India), 30-31 August 2001 12.05.2019