VoIP

VoIP, short for Voice over Internet Protocol, is a method of delivering voice communications and multimedia sessions over IP networks, such as the Internet. It contrasts with traditional circuit-switched telephone networks by packetizing voice data for transmission over data networks.

VoIP systems convert analog audio into digital signals, encode them with codecs, packetize into IP packets, and transport them using IP protocols. Signaling to establish, modify, and terminate calls is commonly handled by Session Initiation Protocol (SIP) or H.323, while the actual media streams are carried over Real-time Transport Protocol (RTP) or its secured variants.

History: emerged in the 1990s with early software-based telephony, gained mainstream via SIP-based platforms in the 2000s, and today is used in enterprise telephony, consumer services, and mobile apps. It enables integration with data networks and cloud services.

Types and services: VoIP can be hosted in the cloud or deployed on premises as IP-PBX; includes softphones, desk phones, and mobile apps; supports voice, video calls, and messaging. SIP trunks connect traditional telephony to VoIP.

Benefits: Lower costs due to using shared networks, easier scalability, geographic flexibility, richer features like call forwarding, voicemail-to-email, unified communications, and easier integration with IT systems.

Limitations: Relies on broadband quality; performance depends on network QoS; latency, jitter, and packet loss affect call quality; power outages can disable phones unless powered; emergency services reliability; security concerns.

Security and standards: Security measures include encryption: SRTP for media, TLS for signaling. NAT traversal issues; regulatory requirements like E911 in some jurisdictions.

VoIP continues to evolve with WebRTC and integrated communications.