Call Control with SIP Brian Elliott, Director of Engineering, NMS

Slide 2 SIP = Session Initiation Protocol SIP version 2.0, RFC 3261, June 2002 RFCs 2976, 3262, 3265, 3515 Protocol for IP networks Transported over UDP, TCP, SCTP, etc. Session (call) control — not a media transport (use RTP), but has a text messaging capability Text-based protocol SIP transports SDP — Session Description Protocol Describes media session — RFCs 2327, 3264 Text based protocol

Slide 3 SIP Among IP Protocols

Slide 4 SIP Network Infrastructure Outbound Proxy Server User Agent B Inbound Proxy Server User Agent A SIP SIP (before connected) SIP Media (RTP) DNS Server DNS Presence/Redirection/ Registration Servers SIP (after connected) SIP

Slide 5 SIP Infrastructure Components User Agent Consists of User Agent Client (to make requests) and User Agent Server (to handle requests) SIP phone, PDA, PSTN gateway, media server Proxy servers Aggregate and route — resolve addresses with DNS Location servers Updated by User Agent registration; queried by proxies in routing

Slide 6 SIP Messages Message types Requests Responses Every request has one or more responses Transaction = request + responses Dialog (or “call leg”) analogous to PSTN call

Slide 7 Messages — Requests INVITE— initiate a session ACK— acknowledge a session PRACK— provisional acknowledge CANCEL— cancel INVITE request BYE— terminate a session REGISTER— register user OPTIONS— query capabilities SUBSCRIBE — subscribe to a service NOTIFY— service notification INFO— miscellaneous info REFER— refer one user to another (transfer)

Slide 8 Messages — Responses 1xx — provisional 100 — Trying 200 — Ringing 300 — Session Progress 2xx — success 200 — OK 3xx — redirection 300 — moved permanently 301 — moved temporarily 4xx — client error 400 — Bad Request 401 — Unauthorized 403 — Forbidden 404 — Not Found 481 — Call Does not Exist 486 — Busy Here 5xx — server error 6xx — global failure

Slide 9 SIP Addressing Uniform Resource Indicators (URIs) Look like addresses

Slide 10 SIP Message Format

Slide 11 Message Flow — SIP “Call”

Slide 12 SIP for NCC 1.0 To allow implementation of SIP User Agent using Natural Access framework Familiar Natural Access development environment Familiar Natural Call Control (NCC) API and model

Slide 13 Benefits of SIP for NCC Reduced time-to-market with SIP-based products SIP integrated into Natural Access NCC API well known NCC API abstracts many low-level details of SIP, simplifying development Easy conversion of PSTN applications using Natural Call Control Pay for SIP stack as you deploy No large up-front license fee

Slide 14 Application or Service For Building SIP User Agents VOIP Network SIPRTP NMS SIP Media Processor SIP Devices SIP RTP

Slide 15 Typical Uses for NMS SIP for NCC Terminate VoIP Bearer Traffic VoIP-PSTN Gateway Interworking Functions SIP Telephony Application VoIP-PSTN Gateway Media Server VoIP Network SIPRTP VoIP Network SIPRTP PSTN/PBX Network SS7, ISDN, CAS TDM Application Server VoIP Network or PSTN/PBX Bearer Traffic SIP

Slide 16 SIP for NCC — Landscape

Slide 17 SIP for NCC Model

Slide 18 Basic Call Control Features Placing outbound call; receiving incoming call INVITE, ACK, CANCEL, BYE 1xx, 2xx PRACK (Provisional Reliable Acknowledgement) Rejecting call with different causes 3xx, 4xx, 5xx, 6xx Transferring call REFER Macros provided for building up fields for SIP and SDP

Slide 19 Special Features Finding users and services REGISTER (nccRegisterUser) SIP event notification SUBSCRIBE, UNSUBSCRIBE, NOTIFY Advanced Configuration Transport options — UDP or TCP Outbound proxy — specify SIP proxy for sending all messages Persistent TCP connection reused instead of setting up and tearing down for each session Configure Ethernet port to be used for all SIP in/out, or designate Ethernet connection per session For future release… OPTIONS, INFO, COMET, UPDATE

Slide 20 Flows — Optional Call Acknowledge nccAcknowledgeCall (callhd, Ies) NCCEVN_ANSWERED_CALL Manual or automatic — server option

Slide 21 Call Transfer

Slide 22 Provisional Acknowledge

Slide 23 Operating Systems Windows Windows 2000 SP4, Windows 2003 Server Linux Red Hat Linux ES 3.0 Update 4 Solaris SPARC 9, 32-bit and 64-bit Intel 8, 32-bit

Slide 24 Obtaining SIP for NCC 1.0 Download from NMS web site Natural Access SIP for NCC 1.0 License Downloaded version licensed for 8 ports for 30 days, for evaluation purposes Contact NMS for deployment licenses

Slide 25 Package Contents Software package Nmssip — server component Sipmgr — SIP manager with NCC service Nccxsip.h — SIP extensions to NCC API Ctasip — NCC + VCE + MSPP SIP demo Documentation SIP for Natural Call Control Developer’s Reference Manual

Slide 26 CTASIP Demo Program

Slide 27 CTASIP Demo Program CTATEST-like demo program for SIP Places and receives SIP calls Performs SIP user registration 3 modes of audio support SIP only — no audio Audio from RTP using Fusion and CG board Audio from RTP using Fusion and HMP

Slide 28 Questions? PLEASE SEE THE SIP DEMO Contact Info