8 1/221 02-FGB 101 327 Uen A - December 2006
4 Access Network
The access network for the Ericsson W25 (FWT) is the WCDMA/HSDPA
Radio access network and belonging core network.
GGSN
ATM/
IP
SGSNFWT RNCBS
MGW
MNC
IMS
Since Fax devices are sensitive to timing, they key features to get a reliable
fax service are bandwidth, latency and jitter. The biggest contributor to
delay and jitter in the IP network is the radio network. To keep the delay
and jitter to a minimum a HS(D)PA connection is required. To further
improve the QoS it would be ideal to have an own PDP context for fax
traffic with high priority. This can also be useful, when the fax service
provider is not the same as the broadband provider.
4.1 Ericsson Solution
The Ericsson W25 is tested together with Ericsson’s Radio Access Network
(RAN). Release P5 of the RAN will be released at the same time as the Fax
over IP function in Ericsson W25, so that’s the target for Ericsson W25.
Later on a release P6 will be available, which enables more user scenarios
and QoS.
4.1.1 Ericsson RAN P5
With P5 the only suitable solution is to use one PDP context for the fax
signaling and stream as well as other IP traffic like internet browsing, due to
multi RAB (Radio Access Bearer) limitations.
4.1.2 Ericsson RAN P6
This version enables the possibility to run multiple PDP contexts without
any performance hits on up or downlink. So this makes it possible to use a
separate PDP context for the fax signaling and stream and other PDP
context for the remaining IP traffic. This can be useful when the Internet
service provider and fax solution provider is not the same provider.
Internet
RAN
IP
