Store-and-Forward Fax
The transmitting gateway is referred to as an “on-ramp gateway,” and the terminating
gateway is referred to as an “off-ramp gateway.” Figure 2-8 illustrates the operation of
on-ramp and off-ramp gateways.
Figure 2-8 Store-and-Forward Fax Topology
The following are some of the basic characteristics of on- and off-ramp faxing:
■ On-ramp faxing: A voice gateway that handles incoming calls from a standard fax
machine or the PSTN converts a traditional G3 fax to an e-mail message with a
Tagged Image File Format (TIFF) attachment. The fax e-mail message and attachment
are handled by an e-mail server while traversing the packet network and can be
stored for later delivery or delivered immediately to a PC or to an off-ramp gateway.
■ Off-ramp faxing: A voice gateway that handles calls going out from the network to a
fax machine or the PSTN converts a fax e-mail with a TIFF attachment into a traditional
fax format that can be delivered to a standard fax machine or the PSTN.
On-ramp and off-ramp faxing processes can be combined on a single gateway, or they
can occur on separate gateways. Store-and-forward fax uses two different interactive
voice response (IVR) applications for on-ramp and off-ramp functionality. The applications
are implemented in two Toolkit Command Language (TCL) scripts that you can
download from Cisco.com.
The basic functionality of store-and-forward fax is facilitated through Simple Mail
Transfer Protocol (SMTP), with additional functionality that provides confirmation of
delivery using existin
On-ramp receives faxes that are delivered as e-mail attachments.
V
PSTN
Off-ramp sends standard e-mail messages that are delivered as faxes.