VoIP Fundamentals¶
Introduction to VoIP¶
Voice over Internet Protocol (VoIP) converts analog voice signals into digital packets for transmission over IP networks.
How VoIP Works¶
Signal Conversion Process¶
- Analog to Digital - Voice converted to digital signal
- Packetization - Digital signal divided into packets
- Transmission - Packets sent over IP network
- Reassembly - Packets reassembled at destination
- Digital to Analog - Converted back to voice
Key Components¶
Endpoints¶
- IP Phones
- Softphones
- Analog Telephone Adapters (ATA)
- VoIP gateways
Infrastructure¶
- VoIP servers/PBX
- Session Border Controllers (SBC)
- Media gateways
- Signaling gateways
Quality Factors¶
Network Requirements¶
- Bandwidth - Minimum 100kbps per call
- Latency - Less than 150ms one-way
- Jitter - Less than 30ms variation
- Packet Loss - Less than 1%
QoS Implementation¶
- DSCP marking
- Traffic prioritization
- Bandwidth reservation
- Jitter buffers
Codec Selection¶
Common Audio Codecs¶
- G.711 - Uncompressed, 64kbps
- G.729 - Compressed, 8kbps
- G.722 - HD voice, 64kbps
- Opus - Adaptive, 6-510kbps
Advantages of VoIP¶
- Cost savings
- Scalability
- Mobility
- Feature richness
- Integration capabilities