Building Telephony Systems with OpenSIPS 1.6 -- Table of Contents -- Building Telephony Systems with OpenSIPS 1.6 -- Credits -- About the Author -- About the Reviewers -- Preface -- What this book covers -- Who this book is for -- Conventions -- Reader feedback -- Customer support -- Errata -- Piracy -- Questions -- 1. Introduction to SIP -- SIP basics -- SIP operation theory -- SIP registering process -- Server operating as a SIP proxy -- Server operating as a SIP redirect -- Basic messages -- SIP dialog flow -- SIP transactions and dialogs -- The RTP protocol -- Codecs -- DTMF relay -- Real Time Control Protocol (RTCP) -- Session Description Protocol (SDP) -- The SIP protocol and the OSI model -- VoIP provider, the big picture -- SIP proxy -- User administration and provisioning portal -- PSTN gateway -- Media server -- Media Proxy or RTP Proxy for Nat traversal -- Accounting and CDR generation -- Monitoring tools -- Where you can find more information -- Summary -- 2. Introduction to OpenSIPS -- Where we are -- What is OpenSIPS? -- OpenSIPS history -- Main characteristics -- Speed -- Flexibility -- OpenSIPS is extendable -- Portability -- Small footprint -- Usage scenarios -- OpenSIPS configuration file -- Core and modules -- Sections of the opensips.cfg file -- Sessions, dialogs, and transactions -- Message processing in the opensips.cfg -- SIP proxy-expected behavior -- Stateful operation -- Summary -- 3. OpenSIPS Installation -- Hardware requirements -- Software requirements -- Lab-installing Linux for OpenSIPS -- Downloading and installing OpenSIPS v1.6.x -- OpenSIPS console -- Lab-running OpenSIPS at the Linux boot -- OpenSIPS v1.6.x directory structure -- Configuration files (etc/opensips) -- Modules (/lib/opensips/modules) -- Binaries (/sbin) -- Log files -- Redirecting OpenSIPS log files -- Startup options -- Summary.

4. Script and Routing Basics -- Where we are -- Scripting OpenSIPS -- Global parameters -- Listen interfaces -- Logging -- Number of processes -- Daemon options -- SIP identity -- Miscellaneous -- Standard script for global parameters -- Modules and their parameters -- Standard configuration for modules and parameters -- Scripting basics -- Core functions -- Core values -- Core keywords -- Pseudo-variables -- Script variables -- Attribute-Value Pair (AVP) overview -- Flags -- The module GFLAGS -- Statements -- if-else -- Switch -- Subroutes -- Routing basics -- Routing requests and replies -- Initial and sequential requests -- Sample route script -- Using the standard configuration -- Common issues -- Daemon does not start -- Client unable to register -- Too many connections -- Summary -- 5. Adding Authentication with MySQL -- Where we are -- The AUTH_DB module -- The REGISTER authentication sequence -- Register sequence -- Register sequence code snippet -- The INVITE authentication sequence -- INVITE sequence packet capture -- INVITE code snippet -- Digest authentication -- WWW-Authenticate response header -- The Authorization request header -- QOP-Quality Of Protection -- Plaintext or hashed passwords -- Installing MySQL support -- Analysis of the opensips.cfg file -- Register requests -- Non-Register requests -- The opensipsctl shell script -- The resource file-opensipsctlrc -- The opensipsctlrc file -- Using OpenSIPS with authentication -- Enhancing the script -- Managing multiple domains -- Using aliases -- Handling CANCEL request and retransmissions -- Full script with all the resources above -- Lab-multi-domain support -- Lab-using aliases -- Summary -- 6. Graphical User Interfaces for OpenSIPS -- OpenSIPS Control Panel -- Installation of opensips-cp -- Installing Monit -- Configuring OpenSIPS Control Panel -- SerMyAdmin.

Lab-installing SerMyAdmin -- SerMyAdmin configuration -- Basic tasks -- Registering a new user -- Approving a new user -- User management -- Domain management -- Interface customization -- Comparing OpenSIPS-CP and SerMyAdmin -- Summary -- 7. Connectivity to the PSTN -- The big picture -- Requests sent to the gateway -- The group module -- Requests coming from the gateways -- The module permissions -- Example -- Inspection of the opensips.cfg file -- Using Asterisk as a PSTN gateway -- Asterisk gateway (sip.conf) -- Cisco 2601 gateway -- Dynamic routing -- Most relevant parameters -- Sort order -- Blacklist -- Force_dns -- Drouting tables -- Case study for dynamic routing -- DIALPLAN transformations -- DIALPLAN example -- Inspection of the file opensips.cfg -- Blacklists and "473/Filtered Destination" messages -- Summary -- 8. Media Services Integration -- Playing announcements -- Example: playing demo-thanks -- Voicemail -- How to integrate Asterisk Real Time with OpenSIPS -- Call forwarding -- Implementing blind call forwarding -- AVPOPS module loading and parameters -- Lab-implementing blind call forwarding -- Implementing call forward on busy or unanswered -- Inspecting the configuration file -- Lab-testing the call forward feature -- Summary -- 9. SIP NAT Traversal -- Why NAT breaks SIP -- Where NAT breaks SIP -- NAT types -- Full cone -- Restricted cone -- Port restricted cone -- Symmetric -- Why symmetric NAT is hard to traverse -- NAT firewall table -- Solving the SIP NAT traversal challenge -- Implementing a near-end NAT solution -- Why STUN does not work with symmetric NAT devices -- Implementing a far-end NAT solution -- The RFC3581 and the force_rport() function -- Solving the traversal of the RTP packets -- RTP Proxy installation and configuration -- Analysis of the file opensips.cfg -- Modules loading -- Modules parameters.

Determining if the client is behind NAT -- Handling REGISTER requests behind NAT -- Handling INVITE messages behind NAT -- Handling the responses -- Handling RE-INVITE messages -- Routing script -- Invite diagram -- Packet sequence -- Lab-using the RTP Proxy for NAT traversal -- Comparing STUN with TURN (MRS) -- Application layer gateways (ALGs) -- Interactive Connectivity Establishment (ICE) -- Summary -- 10. OpenSIPS Accounting and Billing -- Objectives -- Where we are -- VoIP provider architecture -- Accounting configuration -- Automatic accounting -- Multi-leg accounting -- Lab-accounting using MySQL -- Analysis of the opensips.cfg file -- Generating the CDRs -- Lab-generating Call Detail Records -- Accounting using RADIUS -- Lab-accounting using a FreeRADIUS server -- Package and dependencies -- FreeRADIUS client and server configuration -- Configure OpenSIPS server -- Solving the problem with missing BYEs -- Account in the gateway instead of the proxy -- Use SIP session timers -- Use RTP proxy timeout -- Use Media Proxy timeout -- Prepaid and postpaid billing -- Summary -- 11. Monitoring Tools -- Where we are -- Built-in tools -- Trace tools -- SIPTRACE -- Configuring the SIPTRACE -- Stress testing tools -- SIPSAK -- SIPp -- Installing SIPp -- Stress test-the SIP signaling -- Stress test-the RTP signaling -- Wireshark -- Monitoring tools -- Summary -- Index.