Broadband Value-added Services VODSL

VODSL provides a great opportunity for service providers in the data and voice communications market, including the exchange of free competition (cles) and the Voluntary Exchange Bureau (ILECS). It originated in the 1996 United States Telecommunications Organization of an action, and greatly promote the telecommunications industry competition and development.

Because of the growing demand for telecommunications, high-speed Internet access is the largest market for new service providers. In recent years, wired modem and DSL are the most suitable methods for carrier transport services for various types of users.

At the same time, the price of E1/T1 is the 4~5 times of the symmetric DSL (SDSL), so the symmetrical DSL (SDSL) is more suitable for the commercial aspect than the bandwidth access. For the transmission of voice, the application of the choice is still asymmetric DSL (ADSL), mainly because he provides a single line of traditional telephone business support. ADSL is not suitable for commercial use when single line telephones and residential applications are ripe. In order to better the development of small and medium-sized business services, services must be able to provide multi-line voice and data. To this end, service providers can now provide voice and data transmission services with a copper axis as a physical connection.

First, broadband DSL

In transport, many technologies support voice and data transfer. When data transmission is optimized, synchronous transmission requires a given address to ensure the quality of long-distance calls. The increasingly sophisticated VODSL solution does not change the voice network access model for data and speech, it just changes the technology of data and voice access networks.

As with services provided by service providers, the programs that support DSL voice services are constantly changing. When we look at these technologies, we can learn a lot from previous lessons. In particular, early VoIP technology was less successful because quality of service QoS was not ensured across the network. Also, because H.323 supports VoIP voice, video and data at the same time, it appears to support voice is not too single-minded. Data transfer can be performed without regard to the process of execution, simply by keeping his original format. Video signals can also be transmitted in the form of data transmission, as long as the QoS and minimal image latency can be maintained. Today's video compression scheme, for the current data transmission standards have been quite advanced.

For current VODSL applications, some advocates have benefited by limiting the range of networks that maintain QoS (voice compression has enabled QoS throughout the network). An example is to make IP mode work very effective by optimizing H.323 internal VoIP architecture, maintaining IP frames, and using q.931 signaling. This mode enables AudioCodes-based tp/200/400/600 and mp100/200 gateways to link to IP networks and transmit the IP packets to the remote tp/200/400/600 gateway via the DSL topology. This variant of VoIP is only a solution for VODSL applications. Other examples are the use of ATM or Frame Relay virtual circuits to transmit IP packets. AAL2 is used to create a voice virtual circuit that uses a q.931 signaling to implement point-to-point links between the gateway and the Center office or the CLASS5 switch.

In VODSL applications, DSL devices are particularly important to service providers. The new integrated solution should support all VODSL access, including improved VoIP and ATM/Frame Relay methods. An embedded AC48XXX DSL router is sufficient to support the various network type structures that require a DSL. Multiple transport priorities can coexist on the same platform, and DSL routers make selections at both the 2nd and 3rd levels. QoS is guaranteed at the IP level, and the 2nd tier priority queue guarantees frame relay or ATM transmission, such as ALL2 is a standard method. Signaling between a user's voice network and a voice gateway is transparent to dslar, because communication flows between the client terminal device and the voice gateway are transmitted. As with internet access a few years ago, VODSL offers a great market opportunity for innovative service providers. But because there are a variety of technical ways to achieve access, so operators need to pay close attention to the compatibility of DSL devices and call quality.

Second, the Intelligent network VoIP

For many people, the smart Web is a parallel to the No.7 signaling network and the database that provides advanced telephony services. Over the past 25 years, the intelligent network has developed into a ubiquitous network, has become a user data, routing table, service logic, billing data and so can provide more advanced services network. In fact, even today's ordinary phones rely on the intelligent network to complete some functions. Although the Intelligent network is an independent parallel network, it has developed into a part of today's Circuit exchange network. It has served as the basic role of transport services and has provided a number of intelligent services on the PSTN. So can we imagine how much of this leverage is going to be in the IP telephony market?

Before researching a smart network that supports VoIP, it is useful to look at the network structure of the PSTN today. In the central office, the CLASS5 switch provides subscriber lines, line switching, basic call control, and internal phone transmission. Central Office signaling is often transmitted using a highly reliable No.7 network, which is part of the infrastructure of the intelligent network. The packet switch of the transmission signaling is called the Signaling Transmission node (STPS). Other intelligent network components, especially service control nodes (SCP), Service Management System (SMS), and service Control Environment (SCE), provide many intelligent features for smart networks. Combined with the functions of the CLASS5 switch, the more advanced parts are the features of advanced phone processing, such as number transmission (800/888 toll-free, area code), calling card service (credit card payment), caller ID, call waiting, call display, and various other services. The above structure, or minimal change, enables operators to seamlessly link to and provide reliable telephony services on wired and wireless networks. (☆ Introduction to Programming Network ☆)

As the communications industry begins to support Internet telephony, traditional central offices are undergoing dramatic changes. Based on a single chip exchange, it has now evolved into a "softswitch" of distributed gateways, servers, and new components. Depending on the special signaling support protocol, these "SoftSwitch" are sometimes referred to as gatekeeper and call agents (calls agent). Just as the CLASS5 switch handles signaling on the line network and controls the call, the "SoftSwitch" provides the appropriate functionality on the packet-switched web.

Internet telephony providers pay more attention to the leverage of smart networks. For operators, investment in Intelligent Network has special practical significance. Usually these operators spend many years and tens of millions of or even hundreds of millions of of dollars to build their smart network infrastructure. Typical Intelligent Network service providers have a large number of users and complex services. These services are very difficult and difficult to replicate. Traditional service providers are not willing to abandon these assets, and they are looking for ways to leverage existing smart networks to support packet-switched environments. The ability to make phone companies and service providers do not change the infrastructure of the smart network is particularly appealing and feasible. In order not to rely on the SCPs of the Intelligent Network, the service provider plans to use the distributed server and its required database and service logic for advanced services. This approach overcomes the drawbacks of the high cost infrastructure of traditional smart networks and the relative complexity and verbosity of developing and configuring new services. Other non-traditional Intelligent network schemes focus on highly decentralized networks composed of widely distributed intelligent functional servers and terminals. A variety of alternative options emerge, some of which are feasible.

As with various industrial organizations, relevant organizations such as Interna-tional telecommunications union,the International Engineering Task Force and ETSI Tiphon are working to establish protocol standards , interfaces, and the network structure that is connected to VoIP. An important development is the ability to support intelligent network services in these environments, especially the ability to transfer No.7 protocols, such as IsUp and Tcap on IP. The work being done is to establish new call processing languages, service creation environments such as Jain, PARLAY, OSPA, and various technologies (such as vxml) that can provide other services.

The communications industry is undergoing radical change, and many new ideas will emerge. Using these resources, service providers can quickly implement existing voice service projects. Those who want to ignore smart networks have to abandon existing services, or spend a lot of time rebuilding these services with different structures. In general, many service providers will use existing smart networks to implement existing services, and over time they will implement new service projects in the appropriate way.