ASCOM VoWiFi System System Description

Voice over wireless fidelity (vowifi) system
Hide thumbs Also See for VoWiFi System:

Advertisement

TD 92313EN

System Description

Ascom VoWiFi System
7 September 2011 / Ver. G

Advertisement

Table of Contents
loading

Summary of Contents for ASCOM VoWiFi System

  • Page 1: System Description

    TD 92313EN System Description Ascom VoWiFi System 7 September 2011 / Ver. G...
  • Page 2: Table Of Contents

    3.1.2 H.450 Supplementary Services for H.323............ 17 3.1.3 Session Initiation Protocol (SIP) ..............17 3.2 VoWiFi Standards ....................18 4 Ascom VoWiFi System Overview................. 18 4.1 Supported Standards .................... 20 4.1.1 VoWiFi Handset .................... 20 4.2 System Functions ....................20...
  • Page 3 4.3.3 Authentication....................21 4.4 Network Parameter Download................22 4.5 Supported Third-Party Products ................22 4.6 WLAN Planning and Deployment for Ascom VoWiFi System ....... 22 5 Ascom VoWiFi System Components ................23 5.1 VoWiFi Handset ..................... 23 5.2 Access Point (AP) ....................23 5.3 Controller .......................
  • Page 4: Introduction

    LANs. Using third-party WLAN products as well as in-house developed hardware and software, the system enables data and voice transmission together with seamless roaming. This document gives a general description of the Ascom VoWiFi solution. It briefly describes WLAN and VoWiFi technologies and standards. Access Point...
  • Page 5 System Description TD 92313EN Ascom VoWiFi System EAP-TLS EAP-Transport Layer Security Enhanced System Service: Unite modules that handle centralised number planning, remote connection, system supervision, fault handling, group handling, message routing, centralised logging, activity logging, and user access administration. ESSID...
  • Page 6 TSPEC Traffic Specification UNII Unlicensed National Information Infrastructure Unite Ascom messaging platform. A generic term for a messaging system that unites different systems, for example System 900, System 9d, and VoWiFi. Unite CM Unite Connectivity Manager: Unite module that enables messaging and alarm handling in a WLAN system.
  • Page 7 System Description TD 92313EN Ascom VoWiFi System WLAN Wireless Local Area Network (LAN): a type of LAN in which data is sent and received via high-frequency radio waves rather than cables or wires. WMM™ Wi-Fi Multimedia™: offers QoS functionality for WiFi networks.
  • Page 8: Wlan

    See section 4.1 Supported Standards for a description of the 802.11 amendments supported by the Ascom VoWiFi system. WLAN Infrastructure There are two types of WLAN topologies: the Ad-Hoc mode and the Infrastructure Mode. The Ad-Hoc mode provides peer-to-peer connectivity where two clients communicate directly with each other via their WLAN cards.
  • Page 9: Controller-Based Access Points

    Controller and are basically just a radio and an antenna. The Controller handles most of the MAC layer all by itself. The use of controller-based APs enhances operation of the VoWiFi system, makes centralized administration over the WLAN possible, and makes it easy to expand the network.
  • Page 10: 802.11A Rf Modulation Standard

    System Description TD 92313EN Ascom VoWiFi System The 802.11b and 802.11g specifications include the following restrictions: Radio Band: 2.4 GHz Maximum Data Rate: 11 Mbps (802.11b) 54 Mbps (802.11g) Operating channels: 1–14 (depending on country regulations) ETSI: 1–13 FCC: 1–11...
  • Page 11: 802.11N Rf Modulation Standard

    System Description TD 92313EN Ascom VoWiFi System The 802.11a specification includes the following restrictions: Radio Band: 5 GHz Maximum Data Rate: 54 Mbps Operating channels: 36–165 (depending on country regulations), see the table below Maximum number of non-overlapping channels: 19–24 (depending on country...
  • Page 12 System Description TD 92313EN Ascom VoWiFi System • Space-time block coding: A transmitter uses more antennas than signal streams to redundantly transmit the transmit signal. This increases the reliability of the signal at the receiver, and reduces the error rate.
  • Page 13 System Description TD 92313EN Ascom VoWiFi System The 802.11n standard defines Modulation and Coding Scheme (MCS), which is combinations of modulation, Forward Error Correction (FEC) coding, and number of spatial streams. The maximum data rate depends on the MCS, channel bandwidth, and GI length. There are 77 MCS values from 0 to 76.
  • Page 14: Access Control And Security

    System Description TD 92313EN Ascom VoWiFi System Access Control and Security Since the physical layer in a WLAN is broadcast over the air, the normal methods to control a conventional LAN cannot be used. To secure the WLAN from intruders, authentication and encryption are important factors.
  • Page 15: Wep

    System Description TD 92313EN Ascom VoWiFi System 2.3.3 WEP is a security method built into the 802.11 protocol. It uses a shared key system, this means to configure a key (basically a password) in the AP. In order for a wireless client to connect to the network they must know the key and type it into their software.
  • Page 16: Proactive Key Caching (Opportunistic Key Caching)

    System Description TD 92313EN Ascom VoWiFi System handover). The amount of time needed for the key exchange is implementation dependant and differs between AP manufacturers. Like WPA, WPA2 has a Pre-Shared Key mode (PSK), WPA2 Personal, designed for SOHO (small office/home office) wireless networks that cannot afford the cost and complexity of an 802.1X authentication server.
  • Page 17: Quality Of Service (Qos)

    This works well for data traffic but voice, and other multimedia in a WiFi network, is highly sensitive to latency increases and throughput reductions and require QoS functionality. When deploying a VoWiFi system, traffic prioritization is needed to ensure the best possible voice quality.
  • Page 18: Tspec Call Admission Control

    Other parameters that can affect the power consumption are Beacon period and DTIM. Location in the system will also affect the speech time. For more details, see the document System Planning, Ascom VoWiFi System, TD 92408EN. Cisco Compatible Extensions (CCX) CCX is a Cisco proprietary collection of functions and requirements.
  • Page 19: Vowifi

    The voice signal is digitized, compressed and converted to IP packets and then transmitted over the network. Since voice is a real-time application, a VoWiFi system must ensure that the data streams are reconstructed accurately and that sufficient mechanisms for network delay detection have been implemented.
  • Page 20: Vowifi Standards

    • H.323 or SIP with or without supplementary services (H.450/RFC's) for telephony Ascom VoWiFi System Overview To enable an enterprise VoWiFi system where voice traffic as well as messaging and alarm handling are possible, both Ascom and third-party developed hardware and software are used.
  • Page 21 System Description TD 92313EN Ascom VoWiFi System In a large system it is strongly recommended to use an IMS3/Unite CM, and when using shared phones functionality it is required. The IMS3/Unite CM is also required for messaging and alarm functions. An Enhanced System Service (ESS) or a Unite CM is needed if individual passwords for shared phones are used.
  • Page 22: Supported Standards

    For use in Cisco WLAN infrastructure, CCKM is supported to speed up the encryption key exchange when roaming in a multi-cell environment. System Functions The Ascom VoWiFi system is designed to enable wireless voice traffic, messaging and alarm handling within an enterprise LAN. For details, see Function Description, Ascom VoWiFi System, TD 92314EN.
  • Page 23: Wlan Functions

    WLAN Functions Common WLAN functions, such as roaming and user authentication, are handled by third- party products. Therefore specific configuration information must be required from the vendors. For details, see Ascom Configuration Notes for third-party products. 4.3.1 Roaming To enable a user to move freely within the WLAN, see section 5.2 Access Point (AP)
  • Page 24: Network Parameter Download

    Network parameters, such as ESSID, must be defined in the VoWiFi Handset to enable network access. Parameters are loaded to the VoWiFi Handset from the PDM. For the Ascom VoWiFi Handset it is also possible to set the parameters directly on the VoWiFi Handset.
  • Page 25: Ascom Vowifi System Components

    TD 92313EN Ascom VoWiFi System Ascom VoWiFi System Components The Ascom VoWiFi system is created using Ascom developed products, as well as third-party products. This section gives a brief description of the components needed. VoWiFi Handset The VoWiFi Handset includes functionality such as wireless telephony, alarm and messaging.
  • Page 26: Radius Server

    Unite module based on the ELISE3 hardware, designed as an all-in-one solution for centralized management of portable devices. Also, it is an IP messaging gateway responsible for the alarm and message handling between the VoWiFi system and the Unite system.
  • Page 27 For a detailed description of the IMS3, see Installation and Operation Manual, IMS3, TD 92762EN. For a detailed description of the messaging and alarm functions, see Function Description, Ascom VoWiFi System, TD 92314EN. For shared phones functionality, see Function Description, Shared Phones in Ascom Systems, TD 92468GB.
  • Page 28: Unite Connectivity Manager (Unite Cm)

    System Description TD 92313EN Ascom VoWiFi System Unite Connectivity Manager (Unite CM) Unite CM is a web-based tool used for device management, messaging and alarm handling. It is also used for the administration of users and groups, for supervision, activity logging, and fault logging.
  • Page 29: Sip Proxy Server

    When connecting to an IP-PBX, it is possible to use a SIP Proxy Server in the IP-PBX instead of a VoIP gateway/gatekeeper. It is important to ensure the interoperability between the SIP Proxy Server and the WLAN. See the Ascom extranet > Sales tools > Interoperability. Administration Tools Tools for the following VoWiFi functions are defined: •...
  • Page 30: System Solution When Connected To Ip-Pbx

    System Description TD 92313EN Ascom VoWiFi System System Solution When Connected to IP-PBX Messaging client Messaging Send Other Unite Send Send modules Access Points VoWiFi Handsets IMS3/ Unite CM Location Server Presence Management System IP-PBX PSTN Figure Figure 13. Connection to other systems and to IP-PBX...
  • Page 31: Related Documents

    TD 92599EN Configuration Manual, Ascom i62 VoWiFi Handset TD 92675EN Data Sheet, Ascom i62 VoWiFi Handset TD 92587EN Data Sheet, DP1, Desktop Programmer for Ascom i62 VoWiFi TD 92749EN Handset Data Sheet, CR3 Charging Rack TD 92628EN Data Sheet, CR4 Battery Pack Charger...
  • Page 32: Document History

    16. • New supported standards and features in i75 VoWiFi Handset. • Appendix A: Ascom User Documentation on page 32. 26 September 2008 • Added information about Device Management on page 26. • Added information about location in chapter 7 Connection to Other Systems on page 27.
  • Page 33 System Description TD 92313EN Ascom VoWiFi System Version Date Description 7 September 2011 • Removed all information related to the i75 handset. • Replaced IMS2 with IMS3. • Replaced WinPDM with PDM. • Minor text and layout changes. 7 September 2011 / Ver. G...
  • Page 34: Appendix A: Ascom User Documentation

    System Description TD 92313EN Ascom VoWiFi System Appendix A: Ascom User Documentation This appendix explains the technical documentation structure and gives a description of each document type. Not all document types exist for all systems. System documents Function 1. System Description (SD)
  • Page 35 System Description TD 92313EN Ascom VoWiFi System System Installation (SI) Primarily explains system-dependent aspects to be considered at system installation and gives an overview of how to install the system. Target groups: technical engineers planning the system and technicians installing it.
  • Page 36 On-Line Help (OH) Gives help and information via the PC screen. Repair Manual (RM) For service and repair on some of the Ascom products. The document describes the repair of a product defined by one of three levels: 1st Line Repair Mechanical/cosmetic repair such as change of housing etc.

Table of Contents