Ericsson W25 Fixed Wireless Terminal for WCDMA/HSPA Mobile Networks Application Note: Fax over IP with Ericsson W25
Contents 2 1 INTRODUCTION .......................................................................3 1.1 BACKGROUND .............................................................................3 2 SYSTEM OVERVIEW ................................................................4 2.1 2.2 2.2.1 2.2.2 2.2.3 2.3 2.4 2.5 THE FAX OVER IP SOLUTION.........................................................4 VOIP NETWORK ...........................................................................5 SIP Server.....
1 Introduction This document gives a brief description of the Fax over IP and the implementation in the Ericsson W25. It also includes a guidance of how to configure the Ericsson W25. 1.1 Background The Ericsson W25 is intended for residential and SOHO applications. The focus for the Ericsson W25 is to enable both broadband data and voice calls using existing 3G network. Additionally support for analog Fax operation is essential when targeting business users such as SOHO users.
2 System Overview Fax over IP is based on Voice over IP. The Voice over IP system utilizes IP technology over broadband networks and uses SIP for control signaling and RTP for media. The differences between Fax and Voice are the codecs. For voice the normal voice codecs are G.711, G.729, AMR etc, but T.38 is used for fax. The voice and fax media are both sent in RTP packets. SIP Server W25 PSTN Networks Access Network Fax GW Analog line Fax over IP Analog line T.30 T.38 T.
2.2 VoIP network The basic building blocks for Voice and Fax over IP are a SIP server and a PSTN gateway with T.38 support. Sometimes the PSTN gateway might consist of two units; Media Controller and Media Gateway. Normally a Session Border Controller (SBC) is used to handle security. ISUP SIP SIP Server MGC-SG SIP W25 SIP/RTP RTP TDM SBC PSTN Networks MGW 2.2.1 SIP Server The SIP server is the heart of VoIP system. It keeps track of the location of each User Agent (UA).
2.2.2.2 Media Gateway (MGW) The Media Gateway (MGW) provides interworking between PSTN and IP media streams, i.e. conversion between circuit-switched TDM (Time Division Multiplexing) bearer circuits and packet-switched media streams (RTP). 2.2.3 Session Border Controller (SBC) The SBC can also be called outbound proxy, which normally is a SIP aware proxy/stateful firewall. If an SBC is used in the network, the User Agent has to be configured to use the SBC for all SIP sessions.
2.4 T.38 and T30 Protocol There are two protocols used to transfer a fax over IP; T.30 [2] and T.38 [3]. T.30 is the protocol that describes the communication process between two fax machines on a circuit-switched network. T.38 is the protocol that describes the process for sending and receiving fax in real-time over a packet network. The protocol makes adjustments for delay, jitter, and dropped packets, which comes with the characteristics of IP networks and radio networks.
3 Ericsson W25 The Ericsson W25 will work as a gateway, using T.38 protocol. The fax terminal shall be connected to the dedicated fax port on the Ericsson W25. Associated to this fax port is a SIP User Agent, which manages and controls the media streams by using the SIP protocol (RFC 3261) towards the SIP server and the PSTN Gateway. Depending on configuration, Fax calls between two FWT on the same radio networks can be sent directly between the FWT’s not using the PSTN. 3.
3.3.2 Echo Canceller To improve the fax transfer the Ericsson W25 also has an echo canceller in accordance with G.168. 3.3.3 QoS The outgoing VoIP related traffic will be prioritized before other traffic from the Ericsson W25 to reduce the uplink delay and jitter. 3.4 Interoperability The Ericsson W25 is interoperable with e.g. Broadsoft, which is included in Ericsson’s IMT (IMS Multimedia Telephony). Other SIP servers and Fax gateways should also work as long as they support SIP v2 (RFC 3261) and T.
4 W25 Configuration For configuration purpose, the Ericsson W25 includes a CLI (Command Line Interface) and a WUI (web user interface) which are accessible as illustrated in the figure below. IP Please also see the document “Ericsson W25 Administrator’s Guide” for more details on Ericsson W25 configuration. 4.1 Fax service To configure the Fax service in the W25 the CLI is used. It can either be done remotely via SSH or via telnet locally with operator or root user access.
4.1.1.1 • user id , which is the public user identification e.g. the phone number xxxxx • password, which is the password for the user id CLI commands The W25 has already one User Agent configured by default, so this needs to be modified. The commands to modify are: cf set ims.user_agent[0].auth_id cf set ims.user_agent[0].user_id cf set ims.user_agent[0].
Note if the proxy[x].address is set to “localhost”, the W25 will not register to any SIP server. To display the entries in the call server, use the following command cf show ims.callserver ims.callserver[0].domain "server.com" .proxy[0].address "host.server.com" .port 5060 .outbound_proxy "" .local_ip_interface "ppp0" The domain parameter is for future use. The proxy[x].port is by default 5060 (according to the SIP standard). The port number only needs to be changed in special case.
Parameter jbig Description Ecm Specifies if ECM should be used or not. (True|False) extended_ roundtrip Enables the support of dealing with extended round trip delays (True|False) data_wait_time This parameter indicates the time for internal buffering appropriate V.21, ECM and non-ECM page data in the case if the end of line or the end of the HDLC frame is not detected. The value range is from 0 up to 100. The default value is to set to 50 which is of 500 ms buffering. One unit is of 10 ms.
It’s recommended to not enable “extended_roundtrip”, since it has been shown that this cause interoperability problems. Not all gateways support recovery packets, but then the recovery packets will be ignored. Note that at the same time as the recovery_packets is increase, the bandwidth requirement increase as well. For more details see [3]. 4.1.4 VoIP timer To avoid that the fax port is used as a telephony port using Voice over IP, it is possible to restrict for how long a voice call is allowed.
5 References [1] Internal System Description IMT (IMS Multimedia Telephony) 3.01551-HSC 113 03/4 Uen [2] T.30 Procedures for document facsimile transmission in the general switched telephone network [3] T.
6 Acronyms and Abbreviations CDMA Code Division Multiple Access POTS Plain Old Telephone Service CLI Command Line Interface PSTN Public Switched Telephony Network DNS Domain Name System QoS Quality of Service E.164 International Public Telecommunication Numbering Plan as described in the ITU-T Recommendation E.164.
7 Appendix A This chapter describes the test results for the End-to-End T.38 interoperability tests that has been performed on the T.38 implemented in W25. The list includes all successful fax machines (The list has the following format: Fax machine, Profile and Speed) AT/T PPF200 MMR, ECM, 200x100 V.29 9600 Brother 6650MC MMR, ECM, 200x100 V.17 14400 Brother 7150C MMR, ECM, 200x100 V.17 14400 Brother MFC 4600 MMR, ECM, 200x100 V.17 14400 Brother MFC 4650 MMR, ECM, 200x100 V.
Okidata OkiOffice 84 MH, ECM, 200x100 V.17 14400 Olivetti OFX-1000 MH, ECM, 200x100 V.29 9600 Olivetti OFX 3100 MH, ECM, 200x100 V.29 9600 Panasonic KX F1600 MH, Non-ECM, 200x100 V.29 9600 Panasonic KX F3000 MH, Non-ECM, 200x100 V.29 9600 Panasonic KX F500 MH, Non-ECM, 200x100 V.29 9600 Panasonic KX F580 MH, Non-ECM, 200x100 V.29 9600 Panasonic KX FP 270 MH, Non-ECM, 200x100 V.17 14400 Panasonic KX FP C95 MH, Non-ECM, 200x100 V.17 14400 Panasonic PX 150 MH, ECM, 200x100 V.
Sharp UX 1400 MR, ECM, 200x100 V.17 14400 Sharp UX 3600M MR, ECM, 200x100 V.17 14400 Sharp UX 460 MR, Non-ECM, 200x100 V.29 9600 Supra 28.8 MacIntosh MR, ECM, 200x100 V.17 14400 Telecom AM 11 MR, Non-ECM, 200x100 V.29 9600 Telecom NP 80 MR, Non-ECM, 200x100 V.29 9600 Toshiba TF 231 MR, Non-ECM, 200x100 V.29 9600 Toshiba TF 421 MR, ECM, 200x100 V.29 9600 Toshiba TF 671 MR, ECM, 200x100 V.17 14400 US Robotics Sportster 14.4 (FaxTalk) MR, ECM, 200x100 V.
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