Session Initiation Protocol (SIP)

The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol for sessions.

These sessions include Internet telephone calls, multimedia distribution, and multimedia conferences. SIP can create, modify, and terminate sessions with one or more participants.

The SIP protocol is a member of the VOIPProtocolFamily.


XXX - add a brief description of SIP history

Protocol dependencies

  • SIP is commonly uses as its transport UDP (default port 5060), TCP (default port 5060) or TLS (default TCP port 5061). SIP signalling may also be compressed and delivered by Sigcomp

  • SIP is commonly used to establish media sessions, e.g. RTP/RTCP streams carrying audio or video data, where session details are commonly negociated using SDP offers/answers

  • PINTs and SPIRITS - Service interworking

  • Number resolution - TRIP and ENUM (IETF Charter for ENUM)

  • Seamless signaling - SIGTRAN and SIP-T

  • IMPP - Instant Messaging and Presence

  • SIMPLE - SIP for Instant Messaging and Presence Leveraging Extensions IETF Charter for SIMPLE

Example traffic



The SIP dissector is fully functional. You can also view SIP message statistics (Statistics SIP…) or view SIP call flow graphs (Statistics VoIP Calls)

Preference Settings

  • Display raw text for SIP message. Default OFF
  • Enforce strict SIP version check (SIP/2.0). Default ON
  • Reassemble SIP headers spanning multiple TCP segments. Default ON
  • Reassemble SIP bodies spanning multiple TCP segments. Default ON

Example capture file

SampleCaptures/aaa.pcap Sample SIP and RTP traffic.

Display Filter

A complete list of SIP display filter fields can be found in the display filter reference

Show only the SIP based traffic:


Capture Filter

You cannot directly filter SIP protocols while capturing. However, if you know the UDP or TCP or port used (see above), you can filter on that one.

External links

IETF Charters:

  • SIP Session Initiation Protocol (sip)

  • SIPPING Session Initiation Proposal Investigation (sipping)

  • SIP More info on Session Initiation Protocol(SIP)


  • RFC3261 SIP: Session Initiation Protocol

  • RFC3262 Reliability of Provisional Responses in the Session Initiation Protocol (SIP)

  • RFC3263 Session Initiation Protocol (SIP): Locating SIP Servers


  • osip The GNU oSIP library

  • SIPp "SIPp is a free Open Source test tool / traffic generator for the SIP protocol" (GPL)


Imported from on 2020-08-11 23:24:44 UTC