This technical white paper gives an introduction to fax over Internet Protocol (FoIP) and explains the various usages and advantages of FoIP including Least Cost Routing (LCR).
Sending faxes in real-time over an IP
network
How to benefit from Fax over Internet Protocol (FoIP) to
send faxes
This technical white paper gives an introduction to fax over Internet Protocol (FoIP) and explains the various usages and advantages of FoIP. FOIP can also be used to implement Least Cost Routing (LCR); this results in cost-effectiveness that is achieved through a reduction in international calls dialed (since calls are translated into a local call at the recipient's country).
WWW.GFI.COM Sending faxes in real-time over an IP network . 2
Introduction Faxing manually is out of date! The time when faxes used to be sent one by one over a public switched telephone network (PSTN) or Integrated Services Digital Network (ISDN) network is gone. Using Internet technology, it is possible to send professional faxes over the Internet at a very low cost. This can be achieved through Fax over Internet Protocol (FoIP) which is a technology that allows faxes to be sent in real-time over an IP network.
This white paper examines the different technologies and protocols available to send faxes.
Introduction....................................................................................................................................2 What is FoIP?................................................................................................................................2 The fax session .............................................................................................................................3 Possibility of Fax over VoIP audio.................................................................................................4 Calling a third party with VoIP .......................................................................................................4 Least cost routing ..........................................................................................................................7 SIP and H.323 session management............................................................................................9 What is H.323?..............................................................................................................................9 What is SIP?................................................................................................................................10 FAXmaker and Fax over IP (FoIP)..............................................................................................14 About GFI ....................................................................................................................................14
What is FoIP? FoIP is a deviation from voice over Internet Protocol (VoIP) as it makes use of a new protocol (T.38) instead of a voice codec. However, both VoIP and FoIP have session management features in common in that both have connection, disconnection and negotiation stages. In VoIP the data is audio and is sent over an audio compression codec for example G.117a which is a lossy compression scheme: a compression method whereby data that is compressed and then decompressed may well be different from the original, but is "close enough" to be useful in some way. In FoIP the data is T.30 fax data instead of audio and T.30 data does not make use of a lossy compression scheme. Since T.30 data is quite compressed in itself, there is no need for compression but mostly data integrity, and as illustrated in the diagram below, FoIP uses a protocol called T.38 to transfer fax data over IP.
WWW.GFI.COM Sending faxes in real-time over an IP network . 3
Voice over IP (VoIP) Fax over IP (FoIP)
Connect Connect
Negotiate Negotiate
T The audio data is passed as a The T.30 fax data is encoded as I compressed audio stream using per the T.38 standard and sent M audio codec selected in the over to the receiving end. E negotiation phase. For example: G.117a.
Disconnect Disconnect
Format of the data passed from sender to receiver in VoIP and FoIP
The fax session
A fax session is a standardized way of transferring images via a communications medium in real-time. The real-time element is necessary to confirm the transfer of the images. Nowadays, this ... [download for more]
