SIP Forwarding Data Sheet

SIP Forwarding (Session Initiation Protocol):  The acronym SIP stands for Session Initiation Protocol and refers to a TCP/IP-based network protocol that can be used to establish and control communication connections of several subscribers. SIP is often used in Voice-over-IP telephony to establish the connection for telephone calls. As a signaling protocol, SIP enables the Voice Over Internet Protocol (VoIP) by defining the messages sent between endpoints and managing the actual elements of a call. SIP is just one method of deploying VoIP; its primary benefit is the fact that it provides a direct connection between private or local telephone systems (private branch exchanges, or PBX) and the public telephone network. This way, individuals and businesses don't need a legacy telephone line in order to connect

SIP versus VoIP

VoIP is a family of technologies that all support sending or receiving voice messages over the internet. SIP is an application protocol used to carry all forms of digital media, including voice messages—so SIP is a specific technology that supports VoIP calls.

What does a SIP address look like?

A SIP address is written in user@domain.tld format in a similar fashion to an email address. An address like As a SIP address is a text, much like an e-mail address, it may contain non-numeric characters.

What is SIP Used For?

SIP is commonly used for internet media that is real-time such as Voice over Internet Protocol (VoIP) phone calls, video conferencing, and instant messaging.  Real-time media is media that is not pre-recorded and is defined by audio, video, and text messaging that needs to be as close to instantaneous as possible.  Any delays or loss in the real-time media generally will not be re-transmitted as by the time the media packets are retransmitted they will no longer be relevant because the “conversation” has already moved past the timeframe to which the packets were relevant.  Because of this time-sensitive requirement, the UDP (User Datagram Protocol) protocol is most commonly used since there is no packet checking and retransmission as seen in TCP (Transmission Control Protocol) therefore allowing packets to be sent more quickly. 

Benefits Forwarding to SIP

  • Make and receive phone calls at lower rates with the ability to communicate with your customers through a Softphone or IP phone.
  • Stay in touch with important contacts such as suppliers and customers while providing cost-effective telecommuting options for employees.
  • Give your business the ability to create a local presence without the cost and red tape of a physical business/office location and the freedom to create new business models such as “virtual offices” and “remote employees”.  
  • Gain instant access to advanced forwarding capabilities that give you the ability to route your incoming calls to different destinations based on a specific time or day.  
  • As SIP forwarding uses the internet business avoids additional costs of costly termination fees and network regulations often associated with landline calls.
  • Use non-AVOXI phone numbers on our network through our SIP Call Forwarding capability, which lets you take advantage of our Outbound Calling services on third-party numbers.

What is AVOXI doing differently?

AVOXI allows for TCP connections to be selected as your default connection type when forwarding calls. By default, your VoIP calls will still be forwarded using a UDP connection. Take advantage of our extension virtual number coverage with the ability to forward calls to a third-party platform. 

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July 9th, 2021


Louise Ross

Updated By:

Louise Ross



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