SIP Trunking with MessageBird

MessageBird’s SIP Trunking solution allows you to make and receive calls via a broadband internet connection.

Read the following topics to get you up to speed before moving on to configuring your origination SIP-Trunk and configuring your termination SIP Trunk.

SIP Trunking solutions

We offer the following SIP Trunking solutions:

SIP Trunk Origination solution

SIP Trunk Origination allows you to receive inbound calls from the Public Switched Telephone Network (PSTN) to your environment, using either Numbers purchased from us, or your own ported numbers.

SIP Trunk Termination solution

SIP Trunk Termination allows you to place calls from your environment to the PSTN, anywhere in the world.

Supported codecs

A Voice over Internet Protocol (VoIP) codec is a technology that determines the audio quality, bandwidth, and compression of VoIP phone calls. MessageBird supports the following codecs for SIP Trunk solutions:

  • ITU G.711 - 64 Kbps (U-Law)

  • ITU G.711 - 64 Kbps (A-Law)

DTMF Support

Dual-tone multi-frequency (DTMF) signaling is a technology used for making calls and navigating Interactive Voice Response (IVR) menus. For every number that is pushed, two tones within the voice frequency band, one high-frequency and one low-frequency, are sent to the call switching center. Each dual-tone represents a specific number, so the switching center knows which number has been dialed, or which option has been selected from an IVR menu.

The version of DTMF that is used for telephone tone dialing is known by the trademarked term Touch-Tone and is standardized by ITU-T Recommendation Q.23. Other multi-frequency systems are used for internal signaling to the telephone network.

MessageBird supports the following DTMF RFCs:

  • DTMF - RFC 4733 (Send/Receive)

  • DTMF - RFC 3833 (Send/Receive)

Learn about how multi DTMF is integrated with Flow Builder.

Supported SIP RFC Standards

The following SIP RFCs are supported by MessageBird:

  • RFC 3261 SIP: Session Initiation Protocol

  • RFC 3262 Reliability of provisional responses in SIP

  • RFC 3311 The SIP UPDATE method

  • RFC 3326 The Reason header field for the SIP

  • RFC 3824 Using E.164 numbers with the SIP

  • RFC 5658 Addressing Record-Route issues in SIP

  • RFC 3665 SIP basic call flow examples

  • RFC 3666 SIP Public Switched Telephone Network (PSTN) call flows

  • RFC 4458 SIP URIs for applications such as voicemail and interactive voice response (IVR)

  • RFC 3325 P-Asserted identity header field

  • RFC 3550 RTP: A Transport Protocol for Real-Time Applications

  • RFC 3605 Real-Time Control Protocol (RTCP) attribute in Session Description Protocol (SDP)

  • RFC 3711 The Secure Real-Time Transport Protocol (SIP)

  • RFC 3840 Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)

  • RFC 3966 The tel URI for Telephone Numbers

  • RFC 4028 SIP session timers

  • RFC 4235 INVITE-initiated dialog event package

  • RFC 5806 Diversion header field

  • RFC 5876 Updates to Asserted Identity

  • RFC 4833 DTMF events

  • RFC 2833 DTMF events

Supported Number formats

MessageBird supports numbers in the E.164 format, which means:

  • Numbers must contain only digits.

  • Numbers may not have any leading ‘0’s.

  • Numbers must start with the country code.

  • Numbers have a maximum of 15 digits. When used in the FROM header, they may or may not have a leading + symbol. When used in the P-Asserted Identity header, they must have a leading + symbol.

We do not support hidden number presentation by using the P-asserted ID header in combination with the Privacy header. Instead, you must use the settings as follows:

  • P-Asserted-Identity: tel:+31850000000

  • Privacy-id: hidden

Please note that for the P-Asserted-Identity we only support the tel URI (RFC 3966 5.1.4 global numbers) in E.164 format. For number presentation and billing, we normally use the From header, unless the P-Asserted-Identity header is present, in which case, that takes precedence.

Origin-based surcharging

Origin-based surcharging is the standard in many European countries. The legislation dictates that calls made from outside the European Economic Area (EEA) to the EEA are charged differently from calls placed and received inside the EEA.

The Caller Line Identity (CLI) in the From header will be used to determine where the call originates from, and if a surcharge is needed. Only numbers in the E.164 format are verified. Incorrectly formatted and/or empty From Headers will automatically be surcharged with the non-EEA rates unless a P-Asserted-Identity header is present and contains a valid EEA tel URI.

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