Index


Telecommunications general information page

    Telecommunication network infrastructure and management

    • Access Gateways Tutorial - A gateway is a network element that acts as an entrance point to another network. An access gateway is a gateway between the telephony network and other networks, such as the Internet. This tutorial presents several application scenarios that utilize an access gateway point between the traditional telephone network and the Internet.    Rate this link
    • Access Mediation Tutorial - Access mediation is the arbitration of call control between disparate networks, resources, users, and services. This process enables carriers to inspect the syntax and content of every signaling message entering or exiting the network. Each message is checked against the carrier's operations policy to determine whether to permit, deny and/or modify the message traffic. Access mediation devices are typically used to mitigate the risks associated with widespread interconnection and network convergence by providing revenue assurance, fraud prevention, and advanced signaling security. This tutorial will take its readers through the concept of access mediation and explain how it can be applied to help carriers regain control of their signaling networks.    Rate this link
    • Application Services Framework Tutorial - Application services framework is a memory-resident software framework that integrates mediation gateways with enterprise middleware technologies into a common application service model    Rate this link
    • Distributed Network Intelligence Tutorial - Prepared as a tutorial on the capabilities and techniques of distributing intelligence in today?s telecommunications systems, this tutorial provides the reader with foundations and principles for advancing the advanced intelligent network (AIN) toward the next level of execution and interoperability.    Rate this link
    • Element Management Systems (EMSs) Tutorial - This tutorial provides a comprehensive understanding of the role of the EMS in the telecommunications network; the functions that are within the domain of EMSs; and trade-offs between various approaches to element management. It is hoped that this information will assist readers by enhancing their basic understanding of these multifaceted components of the evolving network.    Rate this link
    • Embedded Telecommunications Management Network (TMN) Solutions Tutorial - A telecommunications management network (TMN) agent is an application that runs on a network element (NE) that provides one or more management systems the ability to manage the NE. An embedded TMN agent is used to manage a telecommunications device that uses a real-time operating system (RTOS). Embedded TMN agents, as defined by TMN standards, are increasingly becoming the standard for network management. But the embedded environment presents many challenges for developers. This tutorial outlines the steps required to create embedded TMN agents. Covering from what an embedded agent is to how it fits into the overall TMN network management structure to the process of creating embedded TMN agents, this tutorial will explain the challenges and methods available to overcome them.    Rate this link
    • Emerging Multiservice Network Architecture Tutorial - Multiservice network architecture combines the multiple layers of legacy architecture into fewer network elements, thereby removing barriers to operational efficiency and flexibility. Convergence creates a unified network that operates cohesively to promote efficiency, enhance service features, and offer cost savings?key elements of today's competitive marketplace. This tutorial examines major market trends leading to changes in legacy network architecture, which has become complicated and inefficient in its attempts to meet new telecommunications demands. It describes how that architecture has evolved and how it operates today. The next section compares the legacy network with the new converged network and examines the benefits of the new architecture. Finally, the tutorial describes the technology that enables this new paradigm.    Rate this link
    • Full-Service Network (FSN) Tutorial - The full-service network (FSN) is a telecommunications infrastructure capable of providing all of today's known telecommunications applications as well as laying the foundation for future applications. This definition does not imply that the infrastructure is owned by one entity or that only one medium carries all applications. Operators are implementing and investigating multiple network options, including wireless, hybrid fiber/coax (HFC), and fiber-to-the-curb. To date, the major focus has been implementing the FSN in urban environments. This tutorial reviews the FSN as deployed in a rural setting.    Rate this link
    • Intelligent Network (IN) Tutorial - An intelligent network (IN) is a service-independent telecommunications network. That is, intelligence is taken out of the switch and placed in computer nodes that are distributed throughout the network. This provides the network operator with the means to develop and control services more efficiently. This tutorial discusses how the network has evolved from one in which switch-based service logic provided services to one in which service-independent advanced intelligent network (AIN) capabilities allow for service creation and deployment.    Rate this link
    • Intelligent Network (IN) Service Creation Tutorial - Using the intelligent network (IN) approach for supporting telecommunications services enables the use of productivity-enhancing techniques for the creation of new services. This tutorial will explain improvements to IN techniques for telecommunications service creation.    Rate this link
    • International Intelligent Network (IN) Tutorial - In an intelligent network (IN), the logic for controlling telecommunications services migrates from traditional switching points to computer-based, service-independent platforms. This provides network operators an open platform provisioned with generic service components that can interoperate with elements from different vendors, based on published, open-interface standards. This platform can be used to develop new and different services. This tutorial addresses the evolution and direction of the IN based on International Telecommunications Union?Telecommunications Standardization Sector (ITU?T) and European Telecommunications Standards Institute (ETSI) standards development.    Rate this link
    • Internet Model for Control of Converged Networks Tutorial - Convergence technologies are changing the way telecommunications companies will provide voice and data traffic. Telecommunications convergence is the merger of legacy-based time division multiplexing (TDM) architecture with today?s packet-switching technology and call-control intelligence, which allows commercial carriers and service providers to consolidate voice and data networks to provide integrated communications services.    Rate this link
    • Managed Multiservice Solutions Tutorial - This tutorial discusses how a next generation of managed network services can solve the enterprise problem while enhancing the carrier's market position. Enterprises want to focus more on core business issues, not on being a network service provider. Managed network services, as a result, have become an attractive option for more and more enterprises. Carriers are rapidly responding to the market opportunity with such offerings as managed Internet protocol (IP) services, managed frame relay, and virtual private networks (VPNs). A managed multiservice solution is a comprehensive offering that encompasses multiple traffic types and provides quality of service (QoS) guarantees.    Rate this link
    • Managing the Copper Loop in the 21st Century Tutorial - A loop management system (LMS) is a system that automates copper loop-related tasks that are normally performed manually by a technician. The goal of an LMS is to reduce the need for manual intervention related to tasks such as provisioning, loop qualification, testing and troubleshooting, documentation, and recovery from failures. The major benefits attached to this include better service levels and response time, lower operational costs, and faster service provisioning. This tutorial will address the issues, solutions, and benefits related to an LMS within the context of the copper loop.    Rate this link
    • Operations Support Systems (OSSs) Tutorial - operations support systems (OSSs) generally refers to the systems that perform management, inventory, engineering, planning, and repair functions for telecommunications service networks    Rate this link
    • Performance Management for Next-Generation Networks Tutorial - Performance management for next-generation networks consists of two components. The first is a set of functions that evaluates and reports on the behavior of telecommunications equipment and the effectiveness of the network or network element. The second is a set of various subfunctions that includes gathering statistical information, maintaining and examining historical logs, determining system performance under natural and artificial conditions, and altering system modes of operation. This tutorial is a guide for service providers who seek to enhance the performance of their networks. It discusses the challenges service providers face in managing network performance and the key functional areas of performance management.    Rate this link
    • Telephony Billing Tutorial - In telephony, billing involves gathering data for customer use and the provision of features, calculating costs, and invoicing for payment    Rate this link
    • Unified Messaging Tutorial - Unified messaging is the integration of several different communications media to a single interface. In the last few years several companies have created products that they call unified messaging. This tutorial will present unified messaging less as a product and more as a powerful mode of communication. The benefits to subscribers will be discussed, along with considerations for service providers (both traditional telco and Internet service providers), and the ways in which they will benefit from unified messaging.    Rate this link

    Standards

      Transmission technologies

      T1

      T1 is a standardized TDM technology.T1 belongs to the physical layer in the OSI reference model.T1 lines mostly connect between PABX?s and CO?s. The T1 standard is mostly deployed in USA.The T1 interface provides a 1544 kbit/s access rate. It can support up to 24 user channels, each of 64 kbit/s access rate. T1 interface is generally transported through 100 ohm twisted pair wiring terminated to RJ-48 ot Batam connector.T1 line can use either alternate mark inversion (AMI) or B8ZS line coding at a bit rate of 1.544 Mbps.The T1 interface supports 4 different bit structures, dictated by the mode of operation: Frame, Super Frame, Extended Super Frame, and Unframed. These bit structures determine how the bits are interpreted. A T1 frame is constructed of 24 time slots plus 1-framing bit added to them. Each TS is regarded as a channel of 64 kbit/s bandwidth. Frame length is 193 bits (24*8 + 1), and the frame rate is 8 kHz. The Framing bit creates a channel of 8kbit/s and is used for messages, synchronization, and alarms. A Superframe (SF) is structure constructed of 12 Frames, Numbered: 1-12. Extended superframe (also known ad D5 frame) consists of 24 frames.Some implementation of T1 use so called "robbed bit signaling" (also called A/B/C/D signaling).

      T-1 physically separates TX and RX, officially on separate COAX cables, often run on separate twisted pairs. Ti systems use dedicated pairs, not shared with POTS. T1 was developed in the 1960s and was designed to be implemented using 1960s digital logic. Things have advanced a little in the past 40 years, and HDSL is a modern replacement for T1. The original HDSL did 1 Mb bidirectional on two wires, HSDL/2 can do a full T1. Sometimes SDSL technology ise used to deliver T1. Those new systems are really is the functional equivalent of a T1 in terms of provided service, they are just using more sophisticated modulation underneath on one pair rather than two. Incidentally, the choice of traditional T1 vs. HDSL/SDSL is up to the local LEC who delivers the last mile. It is usually cheaper for the telco's to use HDSL/SDSL out there because they don't need all the amplifiers, etc. associated with a true T1, and they need only one wire pair.

      At its generation, it T1 signal is typically 6 Volts peak to peak. This is called 0dbDSX0 (commonly refered to as 0db or dsx0). It is the reference level used at DSX cross connect points. A T1 signal is reduced in strength as it passes through the cable (normal signal attenuation caused by cable). T1 signal degrades at a rate of 4db to 6db per 1000 cable ft depending on wire gauge and splices, etc. When the wire distances are long, repeater amplifiers are added in the middle of the line (at long distances many amplifiers evenly spaced) to the line to amplify the signal so that the T1 connection can travel through long distances. It is not uncommon for received signals on a normal (repeatered) T1 line to be significantly below the level they were transmitted at. At the telco demark (point of hand off of a T1 line at a customer's location) the signal will be between dsx0 and -16 db DSX0 by engineering standard. (-16 db is 16 db below the nominal transmit level and is approximately 1V ptp). Because of the significant signal level differences and the cross talk on telecommunications cables, you need to be careful how to run T1 signal to avoid errors caused by NEXT (Near End Crosstalk). By using individually shielded twisted pair wire, or T-Screened cable with all of the transmit signals at the same level in one bundle and the receive signals at the same level in a separate bundle NEXT can be avoided.

      In a CO, at a T1 DSX, there can be literally 1000s of T1s running through cross connect trays unshielded. This only works because they are all at the same signal level. There is no significant Near End Cross Talk (NEXT) generated.

      You might sometimes hear term DS1. A DS1 is a data format, moving certain bits at 1.544 Mb/s. In days of old, DS1 was carried only on T1, a facility that used special cable {usually}, two pairs, and repeaters every 6000 ft. That technology, by the way, goes back to 1962. Yes, sixty two. More recently, there have been a lot of ways to carry those DS1 bits. An obvious one: in a DS3, with 27 other DS1's. Another is over SHDSL [ITU-T Rec. G.991.2] and likely more, I think HADSL or is it HDSL.

      E1

      E1 is a standardized TDM technology.E1 belongs to the physical layer in the OSI reference model.E1 lines mostly connect between PABX?s and CO?s.The E1 standard is mostly deployed in Europe.The E1 interface provides a 2048 kbit/s access rate. It can support up to 32 user channels, each of 64 kbit/s access rate, though mostly only 30 are used as dedicated user channels. The 64 kbit/s channels are usually used for delivering PCM encoded phone calls, but of course can carry pure data. An E1 line connects two points in one of which the information is multiplexed and in the second demultiplexed. E1 interface is generally transported through 120 ohm twisted pair wiring terminated to RJ-48 ot Batam connector. Other possible transmission media for E1 is 75 ohm coaxial cable terminated using BNC connector. In order to provide a reliable and accurate service the E1 interface supports several mechanisms for synchronization, error correction and detection, management and performance messages and signaling. The E1 interface supports 3 different kinds of bit structures : Frame, Multiframe, and Unframed. The mode of operation dictates how the bits are structured and as consequent the way it will be interpreted.As a consequence of the TDM methodology, each of the E1?s channels is practically carried in one time slot of the 32 time slots the E1?s bandwidth is divided to. The E1 frame length is 256 bits (32 TS * 8 bit each TS). The Frame rate is 8kHz. The time slots in each frame are numbered 0 to 31.16 consecutive frames form a new structure called a Multiframe. The frames in a Multiframe are considered numbered 0 to 15. Multiframe structure is used for two purposes CAS signaling and CRC.

      J1

      Private Branch Exchanges (PBXs) throughout Japan use a J1 interface (2.048 Mbps TDM interface). This interface supports 30 voice channels per port. J1 system uses 110 ohm tristed pair wiring terminated to RJ-48 or Siemens 3-pin connector.


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