Your Hands-On Guide to Voice over IP (VoIP) This book was written for the thousands of IT professionals-from CIOs to circuit-switched telecom engineers-who are now responsible for deploying and maintaining secure VoIP networks. The book explains the impact on your VoIP network of PSTN, SIP, H.323, firewalls, NAT, encryption, and the regulatory environment. Coverage includes evaluation, design, integration, and management of VoIP networking components, including IP telephones, gateways, gatekeepers, registration servers, media servers, and proxy servers. Throughout the book, the authors rely on their extensive real-world experience to provide readers with practical applications and solutions. VoIP Isn't Just Another Data Protocol IP telephony uses the Internet architecture, similar to any other data application. However, from a security administrator's point of view, VoIP is different. Understand why. What Functionality Is Gained, Degraded, or Enhanced on a VoIP Network? Find out the issues associated with quality of service, emergency 911 service, and the major benefits of VoIP. The Security Considerations of Voice Messaging Learn about the types of security attacks you need to protect against within your voice messaging system. VoIP and the Public Switched Telephone Network (PSTN) Understand PSTN: what is it, and how does it work? VoIP Communication Architectures See how products like Skype, H.248, IAX, and Microsoft Live Communications Server 2005 The Support Protocols of VoIP Environments Learn the services, features, and security implications of DNS, TFTP, HTTP, SNMP, DHCP, RSVP, SDP, and SKINNY. Securing the Whole VoIP Infrastructure Your guide to Denial-of-Service attacks, VoIP service disruption, call hijacking and interception, H.323-specific attacks, and SIP-specific attacks. Authorized Access Begins with Authentication Learn the methods of verifying both the user identity and the device identity in order to secure a VoIP network. Secure Internet Mail See how S/MIME provides cryptographic security services for electronic messaging applications.
To retrieve relevant information on a mobile phone without having to open up a web browser is not only easier but also efficient in time-constraint situations. To achieve this, we implemented an Interactive Voice Response System (IVRS) for SIP-based phones. This book aims to propose a cost-effective IVR system using a simple PC without having to set up a physical PBX. Telecommunication services play an important role in exchange of information and communication. Although this system is limited to SIP-based phones, in this book we propose a general IVRS that can be implemented for a regular network operated mobile phone and various architectures that can be implemented through our model. This works in favour of institutes and small-scale companies who wish to implement a help line without the use of a physical PBX.
Voice over IP (VoIP) technology is currently finding its place in the telecommunication market. It enables a telecommunication company to cut cost by allowing a single network to transmit both data and voice traffic. Voice Vox is the complete implementation of VOIP client and also describe how to build telecommunication applications using different layers of the Open Systems Interconnection (OSI) model. The book in your hand will lead you in details how you can develop a system based on all OSI layers. These layers are application, presentation, session, transport, network, data link and physical. In Voice Vox, the reader will find how to design the packets at different layers in order to effectively communicate with each other. At the application layer, Session Initiation Protocol (SIP) is used for establishing sessions between two parties using Asterisk as a telephone private branch exchange (PBX) server. At the session layer, the user can implement Real-time Transport Protocol (RTP) and Session Description Protocol (SDP) for real-time data transmission between two call parties. At the transport layer, the User Datagram Protocol (UDP) is used for the transmission of audio data.
Existing wireless networks enable different important applications over IP based network such as public internet and Voice over Internet protocol is one of the important applications which have become a possible alternative to public switched telephone network (PSTN). This project investigates one of the time sensitive data applications on WiMAX i.e. VoIP. I carried on WiMAX because WiMAX networks provide advance features and protocols to support the Quality of service (QoS). This project also indicates about the impact of load and mobility on the voice calls. This book provides details about the Voice Over Internet Protocol (VoIP), Which includes types of VoIP calls, VoIP System and Components, VoIP Protocols, VoIP codecs and VoIP Quality of Service (QoS). It also provides detailed study of WiMAX including WiMAX Protocol Layer and WiMAX Quality Of Service(QoS)
Model: AJ-CX - Color: White + black - Receive frequency: 315MHz - Transmission frequency: 433MHz - Wireless encoding: ASK - Receive sensitivity: -98dBm@12dB SINDA - Wired alarm siren volume: More than 110dBspl - Supports up to 32 guard areas - Supports up to 5 alarm phone numbers - Built-in 7.2V 550mAh battery - Allows you to set the system status (arm disarm etc) through the telephone by dialing the alarm panel number - Voice recording and auto play voice when the alarm phone call connected - Voice monitoring through telephone - Package includes: - 1 x Alarm panel - 1 x PIR detector (1 x 6F22 battery included) - 1 x Door sensor (1 x 23A battery included) - 1 x Wired siren - 2 x Remote controller (1 x 23A included) - 1 x Power adapter (100~240V / EU plug) - 1 x Phone connection cable - 1 x Chinese/English manual
Voice over LTE (Long Term Evolution) presents the mechanisms put in place in 4G mobile networks for the transportation of IP packets containing voice data and telephone signaling, as well as the technologies used to provide a telephone service in the IMS (IP Multimedia Sub-system) network. Despite the difficulty connected to the handover of the 4G network to the 2G/3G network, a telephone communication will not be established on the 4G network. This book analyzes the technologies that have been put in place, such as CSFB (Circuit Service FallBack), an interim solution that enables a mobile connected to the 4G network to receive an alert transmitted by the 2G/3G network. The book also goes on to develop the SIP (Session Information Protocol) on which the telephone signaling transferred by the 4G network is based, the IMS network that provides the service and defines the routing, the SRVCC (Single Radio Voice Call Continuity) mechanism that maintains communication and the TAS (Telephony Application Server) that supplies supplementary services. Contents 1. The EPS Network. 2. The LTE Interface. 3. The CSFB Function. 4. SIP and SDP Protocols. 5. The IMS Network. 6. Telephone Services. 7. The SRVCC Function. About the Authors André Perez is a consultant and teacher in networks and telecommunications. He works with industrialists and operators regarding architecture studies and leads training on the 4G and IMS networks for NEXCOM.