Normative References and Standards

Blink is built on top of SIP SIMPLE client SDK.

Encryption and Privacy


  • SIP: Session Initiation Protocol RFC3261
  • SDP: Session Description Protocol RFC4566
  • An Offer/Answer Model with Session Description Protocol RFC3264
  • PRACK: Reliability of Provisional Responses in Session Initiation Protocol RFC3262
  • HTTP Basic and Digest Access Authentication RFC2617
  • The Reason Header Field RFC3326
  • MESSAGE: SIP Extension for Instant Messaging RFC3428

Address Resolution

NAT Traversal

  • SIP Signaling: Symmetric Response Routing Symmetric media RFC3581
  • Audio and Video: ICE, Interactive Connectivity Establishment RFC5245
  • IM and File Transfers: MSRP Relay Extension RFC4976 and MSRP ACM RFC6135

Voice and Video over IP

  • RTP: A Transport Protocol for Real-Time Applications RFC3550
  • RCTP: Real Time Control Protocol attribute in Session Description Protocol RFC3605
  • SRTP: The Secure Real-time Transport Protocol RFC3711
  • DTMF: Dual-tone Multi-frequency Signaling RFC2833 and inband
  • MWI: Message Summary Event Package RFC3842
  • Opus, AMR, Speex and G722: Wide-band Internet Codecs
  • G711, iLBC and GSM: PSTN Compatible Codecs
  • H.264, VP8 and VP9 Codecs


Instant Messaging and File Transfer

  • MSRP: Message Session Relay Protocol RFC4975
  • MSRP File Transfers RFC5547
  • CPIM: Common Presence and Instant Messaging RFC3862
  • Indication of Message Composition for Instant Messaging RFC3994

Screen Sharing

Contacts Management


Note: available features may vary depending on OS type and version.