Table of Contents

Preface
Chapter 1: Introduction to SIP
Chapter 2: Introduction to OpenSIPS
Chapter 3: OpenSIPS Installation
Chapter 4: Script and Routing Basics
Chapter 5: Adding Authentication with MySQL
Chapter 6: Graphical User Interfaces for OpenSIPS
Chapter 7: Connectivity to the PSTN
Chapter 8: Media Services Integration
Chapter 9: SIP NAT Traversal
Chapter 10: OpenSIPS Accounting and Billing
Chapter 11: Monitoring Tools
Index
Preface
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Chapter 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
Up
Index