1. VOIP
1.1. VoIP?
1.1.1. A protocol is a set of rules used to allow orderly communication
1.1.2. Supports corporate, private public, cable, and wireless networks
1.1.3. Call forwarding, voice mailbox, call records etc...
1.2. Flavors of VoIP
1.2.1. ATA - Analog Telephone Adaptor
1.2.2. IP Phones - Internet Protocol Phones
1.2.3. Computer-to-Computer
1.3. Common Applications
1.3.1. Skype
1.3.2. Teamspeak
1.3.3. Ventrillo
2. Closer Look at VoIP and SIP
2.1. SIP
2.1.1. Session Initiation Protocol
2.1.2. It can carry a variety of payloads
2.1.3. It can be carried over a variety of different transport protocols
2.2. SIP Messages
2.2.1. SIP request
2.2.2. SIP response
2.3. Protocol Operation
2.3.1. Runs on TCP, UDP or SCTP (two-party or multi-part)
2.3.2. Clients typically use TCP or UDP on ports 5060 or 5061
2.3.2.1. Port 5060 used for non-encrypted signaling traffic
2.3.2.2. Port 5061 used for traffic encrypted with Transport Layer Security (TLS)
2.3.3. Similar design elements as HTTP request/response model
2.4. Network Elements
2.4.1. User Agent (UA)
2.4.2. Proxy Server
2.4.3. Registrar
2.4.4. Redirect server
2.4.5. Session border controller
2.4.6. Gateway
3. Linphone
3.1. Linphone?
3.1.1. Open source SIP Phone
3.1.2. Available on Mobile and Desktop environments
3.2. platform
3.2.1. iOS, Android, Windows Phone 8, Linux, Windows and MAC
3.3. Architecture
3.3.1. The user interface frontends
3.3.2. Liblinphone
3.3.2.1. Mediastreamer2
3.3.2.2. oRTP
3.3.2.3. belle-sip
3.4. Linphone Features
3.4.1. Audio & HD video calls
3.4.2. Multiple calls management (pause & resume)
3.4.3. Call transfer
3.4.4. Audio conferencing
3.4.5. Instant Messaging
3.4.6. Pictures and files sharing
3.4.7. Contact list
3.4.8. Call History
3.4.9. Display of advanced call statistics
3.4.10. Echo Cancellation
3.4.11. Quality of Service
3.4.12. Secure communications: zRTP, TLS, SRTP
3.4.13. Supported languages: English, French
3.4.14. Dedicated tablet user interface
3.5. Linphone Features (Advanced)
3.5.1. Audio Codecs
3.5.2. Video Codecs
3.5.3. HD video support
3.5.4. Push notifications
3.5.5. ICE support
3.5.6. Low bandwidth mode