Today’s telecommunications networks are a delicate blend of clients and servers together that offer virtually endless possibilities when it comes to services and applications. For every new client, there seems to be a score more on the way - from mobile handsets, PDAs, terminals, telephone, video phones, IP set-top boxes, and so on.

There are essentially two types of servers that connect between customers on large networks: proxy server and back-to-back user agent (B2BUA) servers. The more prevalent proxy server feature predictable behavior - simply connecting between customers. Effectively, B2BUA servers are much stronger and intelligent entities that perform actions that proxy server. Moreover, B2BUA servers provide a flexible solution for a wide range of applications and services and are becoming the primary engine for more and more servers in SIP IMS and NGN networks.

The difference between proxy servers and servers B2BUA is sometimes not fully understood. In this article, we will explore what makes B2BUA servers such an appealing alternative to standard proxy server. Better Understanding of B2BUA servers can help managers understand the value and the tradeoffs, B2BUA of choosing a server, as well as the frameworks needed to develop a wide range of applications and SIP SIP services using it.

Figure 1 - Architectural B2BUA difference between server and proxy server

B2BUA server Defined
B2BUA servers are used to provide value added features for point-to-point calls and manage multi-point calls. The Power behind a B2BUA server is mostly derived from the fact that it has a very generic definition, which gives it almost unlimited power. However, this same characteristic is the root of the controversy surrounding it.

IETF standard (RFC 3261) defines a back-to-back user agent as a logical entity that receives a request and processes it as a user agent server (AU). In order to determine how the request should be answered, it acts as a user agent client (UAC) and generates requests. Unlike a server, it maintains a dialogue state and must participate in all requests sent on the dialogue it has established. ”

B2BUA servers have capabilities that far exceed those of other types of SIP servers, and answer the need for developing sophisticated SIP value-added applications that can not be implemented as proxy applications.

Some of these capabilities, which are unique to B2BUA servers are outlined below:

3rd Party Call Control (3PCC) Features
3rd Party Call Control (3PCC) is the ability of an entity (usually a controller) to set up and manage communication between two or more parties. 3PCC is often used for operator services and conferencing.

3PCC measures are important, capabilities, exclusive to servers B2BUA since “passive” does not call stateful elements, such as proxy servers, can not initiate these types of activities. Some examples of 3PCC services are online billing, QoS, resource prioritization, call transfer, click-to-dial, mid-call announcement and more.

3PCC actions can be initiated automatically by B2BUA server applications, like disconnecting a call following the expiry of credit in an online billing system Or they can be initiated by remote control administrative (OSS), eg urges parties to a multi-point conferencing session.

Figure 2 - schematic outline of B2BUA offering server functionality 3PCC

Inter-working Function (IMF) for Interoperability

SIP was designed as a highly flexible and extendible protocol. The very strength of this flexibility is also an inherent weakness, since the vast array of client types in the market still need to connect.

B2BUA Inter-working Functions (IMF) defines a wide range of powerful servers that connect SIP SIP clients that “speak in different dialects protocol, or support different capabilities. This inter-working function is very important in enabling connectivity between customers with different capabilities and / or protocol dialects. Or even between customers and networks - B2BUA where the server actually acts as an access device.

Examples of what the IMF can do include:

• SIP clients Connecting to IMS networks by adding and removing IMS SIP protocol extensions (AKA P-header) that are essential for connecting to the IMS network
• Customer Connecting with different settings session timer
• Customer Connecting with different media and capabilities with separate Session Description Protocol (SDP) by relaying messages between the two types of control meetings
• Connecting to different types of networks (eg IPv4, IPv6), and support for various types of transport, such as TCP / UDP / SCTP / TLS

Figure 3: - schematic outline of a B2BUA Inter-Working Function

Multi-point Call Management

B2BUA years servers also implement multi-point call scenarios where multiple CPE devices to connect the B2BUA, and the B2BUA provides services to all CPE.

Due to these capabilities, single B2BUA servers are widely used in the communications industry. A few examples are listed below:

• Online-billing/prepaid Functions
• Server Resource supporting Prioritization (RP) and / or Quality of Service (QoS) features
• Multipoint Conferencing Server
• IVR server
• PBX switches and software applications
• Application Layer Gateway (ALG)
• FW / NAT traversal applications
• Privacy Servers
• 3rd-party applications Call Control (3PCC)
• Service Creation Environment (SCE) Runtime Engines
• Boarder Session Controller (SBC)
• IMS S-CSCF, P-CSCF, I-CSCF
• SIP Inter-work Function (IMF) Gateway –
• Security Gateway (SEG)
• Voice Call Continuity (VCC) servers

In addition, B2BUA servers play an important role in emerging IMS networks. Recent releases of 3GPP IMS specifications (3GPP TS 24,229 V8.0.0) indicate that an increasing number of servers IMS network element, such as P-CSCF, IBCF, SBC, etc.., Are B2BUA servers. The reason for this is that value added services are usually stateful session, feature and capabilities that go beyond basic call proxying. Applications written on top of B2BUA Application Server fulfil different roles, such as SIP user agents, SIP proxy servers and SIP Registrars.

B2BUA server Challenges

B2BUA application developers from many challenges, such as achieving rapid time-to-market, conformity and interoperability, customization for offering proprietary services and support for High Availability (HA) and redundancy. A comprehensive framework B2BUA can help developers overcome these challenges.

A solid framework should have B2BUA modular architecture application building block for increased flexibility, abstraction and short delivery time. Traditional architecture, which features a state-configurable single machine, is not flexible enough. Also, a B2BUA framework should facilitate developing B2BUA flexible applications by linking “pluggable” high-level Modular Application Building Blocks (MABB). Developers should have the ability to combine these MABBs and they should be designed in a way that allows to customize their behavior further if needed. This type of contemporary architecture with Compline Service Oriented Architecture (SOA) concepts, and is suitable for powering flexible business communications platforms. This modular architecture can save months of work. With a set of MABBs in hand, the application is developing a matter of combining existing MABBs required to produce the business logic. In addition, this architecture enhances efficiency; development of new MABBs can be done concurrently.

A B2BUA framework should facilitate developing applications that fully conform to standards and are interoperable, without restricting developers from customizing protocol behavior for special cases. Moreover, it should conform to non-standard implementations, as well as to mediate between two versions of the same standard. This type of framework allows developers to focus on their proprietary application with the confidence that their final application will be fully interoperable.

And finally, a B2BUA framework should provide the ability to configure, amend and replace application building blocks to create proprietary features. With this ability, developers can maximize existing code - significantly reducing development time, shortening testing cycles, and reducing overall time-to-market.

Figure 4 - Traditional architecture of a framework B2BUA

RADVISION’s B2BUA Application Framework http://www.radvision.com/Products/Developer/SIPServer delivers these capabilities and more. The B2BUA module Application Framework is a part of the RADVISION SIP Server Platform, a software framework that offers the essential building blocks for the development of a wide variety of high performance and IMS SIP server. The rich set of components and modules can be flexibly combined to match customers’ requirements for developing SIP servers that offer both standard and advanced SIP services.

Applications written on top of RADVISION’s B2BUA framework are developed by combining modular, customizable application building blocks. This is effectively large chunks of functionality that can be strung together to form ad hoc applications, enabling developers to focus on the high-level business logic and use building blocks that hide low-level details.

As one of the most popular IM applications, Yahoo! Messenger was the first player that large consumer adopted B2B UA. Yahoo! Messenger combined its backend scalable platform with RADVISION’s B2B UA to serve millions of monthly unique messaging users around the world. Yahoo B2BUA selected RADVISION’s due to its robust performance and scalability features.

Figure 5 - The architecture of RADVISION B2BUA Application Framework

RADVISION also provides automatic High Availability (HA) and redundancy support. The framework B2BUA automatically replicates the run-time state of the different and Services Framework B2BUA core. In the event of a server outage, a redundant server takes over seamlessly and provides uninterrupted service continuity.

B2BUA Framework benefits in a nutshell

• Significantly reduces time to market developing proprietary B2B applications and services.
• Allows easily adding advanced services to retain competitive advantage and evolve to meet growing customer demands.
• Focuses on the business logic and hides low level communications operator intricacies.
• Delivers off-the-shelf conformity and interoperability.
• Enables rapid development of applications that can interoperate with different vendors.
• Third adding high-availability features easily.Aujourd ‘hui, the telecommunications networks are a delicate mix of clients and servers, which together offer virtually unlimited possibilities in the area of services and applications. For each new customer, it seems a customer more on the way - from mobile phones, PDAs, terminals, telephones, video, IP set-top boxes, and so on.

There are basically two types of servers, under which the customer on the major networks: proxy server and back-to-back user agent (B2BUA) servers. The most popular proxy server functionality predictable behavior - simply the connection between the customer. Because B2BUA servers are much smarter and organisations involved in the implementation of measures proxy servers that can not. In addition B2BUA uses a flexible solution for a wide range of applications and services and are developing as the main engine is always more SIP servers in the NGN and IMS networks networks.

The difference between the server and proxy servers B2BUA is sometimes not properly understood. In this article, we explore what these servers B2BUA an attractive alternative to the standard proxy server. A better understanding B2BUA servers can help managers to the value and compromises, select a server B2BUA, as well as the necessary conditions for the development of a wide range of SIP SIP applications and services to help.

Figure 1 - schema architecture difference between server and proxy servers B2BUA

B2BUA server
B2BUA servers, added value for point-to-point and to manage the calls of more than one point calls. The energy behind a server B2BUA comes in large part the fact that it is a very general, which gave him an almost unlimited. But even this property is the reason for the controversy that surrounds him.

IETF standard (RFC 3261) defines a back-to-back agent as “a logical unit, which is a requirement receives and processes, such as a user agent server (FH). To determine how the question must be answered, it acts as a user agent client (UAC) generated and the requests. In contrast to a proxy server, he leads a dialogue condition and need to all questions in the dialogue, which he has created. ”

B2BUA server, the capacities are far above those of other types of SIP servers, and the answer to the need for the development of value-added advanced SIP applications that can not be implemented in the proxy.

Some of these capabilities, the B2BUA only in servers, are listed below:

3rd Party Call Control (3PCC) Technical Data
3rd Party Call Control (3PCC) is the ability of a company (usually a controller) for the establishment and management of communication between two or more parties. 3PCC is often used to secure the services of the operator and the conference.

3PCC measures are important resources, has an exclusivity of servers since B2BUA “passive”, not “call stateful elements such as proxy servers that can not open this type of activities. Some examples from the 3PCC online billing, QoS, the hierarchy of resources, call transfer, click on-line, medium-call display and more.

3PCC measures can be taken automatically by B2BUA server applications, such as the separation of a call to end the on-line credit in the accounting. Or they can be initiated remotely control the administration (OSS), for example, the call on the parties to a more than one point of the conference to register.

Figure 2 - Draft Plan for B2BUA server function offer 3PCC

Inter-function for work (IMF) for interoperability

SIP has been very flexible and expandable protocol. The strength of this flexibility is also a weakness, because the variety of types of customers in the market still have a connection.

B2BUA work functions (IMF) is a wide range of high-performance servers connect the SIP SIP clients that “talk” in the various dialects protocol, or supporting various capacities. This function of inter-work is very important so that the connection between the clients with different capacities and / or dialects protocol. Or even between customers and the networks - on which the B2BUA server acts as an access.

Examples, what can the IMF include:

Sign • SIP clients from SGI networks add and remove the SGI SIP protocol extensions (AKA P-header), which are essential for connecting to the network IMS
• connect customers with different settings session timer
• connect customers with different media and with the skills separate Session Description Protocol (SDP) of embassies between the two types of meetings control
• connection to various types of networks (such as IPv4, IPv6) and the support of various types of transport, such as TCP / UDP / SCTP / TLS

Figure 3 - Schedule outlines B2BUA interaction function of work

More than one point for the management of calls

B2BUA servers, the establishment of a multi-point call scenarios in which multiple devices connect to the CPE B2BUA, B2BUA and provides services for all EP Committee.

Thanks to these unique capabilities, B2BUA servers are widely used in the communications industry. Some examples are listed below:

• Features Online-billing/prepaid
• server to support the priorities of resources (RP) and / or Quality of Service (QoS) features
• Multipoint Conferencing Server
• IVR server
• PBX switches and software applications
• Application Layer Gateway (ALG)
• FW / NAT traversal applications
• Privacy server
• 3 Part-Control applications call (3PCC)
• establishment of the service environment (SCE) the performance of engines
• Boarder Session Controller (SBC)
• S IMS CSCF, P-CSCF, I-CSCF
• Inter-SIP work function (IMF) Gateway
• Security Gateway (SEG)
• vocal call continuity (VCC) server

The server B2BUA play an important role in the new IMS networks. The recent release of 3GPP IMS specifications (3GPP TS 24229 V8.0.0) show that a growing number of elements of the IMS network servers, such as P-CSCF, IBCF, SBC, etc. are B2BUA servers. The reason is that value-added services are usually stateful session, and have the capacity to call on the proxying. The applications on servers with the application B2BUA fill several roles, as the officials users SIP, SIP and SIP proxy servers, the registrars.

B2BUA server challenges

B2BUA the developers of applications have many challenges, such as the rapid implementation time for the market, the conformity and interoperability, specialities of the individualization of services and support for high availability (HA) and redundancy. A framework can B2BUA developers in addressing these challenges.

A solid framework B2BUA would use a modular, modular architecture for greater flexibility, the abstraction and short delivery times. The traditional architecture, a unique machine state, not flexible enough. A B2BUA framework, the development of applications by flexibility B2BUA “pluggable” high-level application Modular Building Blocks (MABB). The developers should be allowed to use them Mabbs, and they should be developed in a way that it allows developers to adjust their behavior if necessary. This type of architecture Service Oriented Architecture (SOA) concepts and is responsible for the power supply flexible business platform of communication. This modular architecture can save months of work. With an ensemble of Mabbs in hand, the development of demand, is a matter of combining existing Mabbs to the logical business. Moreover, this architecture improves the efficiency, development of new Mabbs can simultaneously.

A B2BUA framework, the development of applications fully consistent with the standards and interoperability, without the developer the behavior of a protocol for special cases. In addition, the norm is not implemented, so that the mediation between the two versions of the same level. This kind of framework allows developers to focus on their implementation with the confidence that their application finals will be fully interoperable.

And finally, a B2BUA framework should be able to configure, modify and replace as the basis for the creation of elements of the property. With this capability, the developers will use the existing code - significantly reduce the time for development, shorten the test, and the overall reduction of time on the market.

Figure 4 - the traditional architecture of a B2BUA

RADVISION of B2BUA http://www.radvision.com/Products/Developer/SIPServer Application Framework offers these possibilities and more. The module B2BUA Application Framework is part of RADVISION SIP server platform, software, the essential elements for the development of a variety of high-and IMS-SIP servers. The rich collection of components and modules can be combined flexibly to the needs of customers in the development of SIP servers, the SIP standard and services.

The applications included in the above B2BUA RADVISION framework be developed in combination the application adaptable modular basis. This is actually the large pieces of functions, which together can be made to ad hoc applications developers, at a high level of the business logic and use of blocks, low hide details.

As one of the most popular instant messaging applications, Yahoo! Messenger was the first major player, the consumer has B2B UA. Yahoo! Messenger combines back-scalable platform with RADVISION B2B AU to millions of visitors per month, the e-mail users around the world. Yahoo RADVISION, select the B2BUA due to its excellent performance and scalability features.

Figure 5 - The architecture of RADVISION B2BUA Application Framework

RADVISION also offers automatic High Availability (HA) and redundancy. The framework B2BUA automatically reproduced the run-time status of the different services and B2BUA framework. In the case of a breakdown of the server, a redundant server so transparent, so that continuity of service.

B2BUA part of the services at a glance

• reduces significantly the time of the development of B2B property of applications and services.
• Third adding advanced services easily, a competitive advantage and evolve to meet the growing demand of customers.
• focuses on the business logic and low operator hides subtleties of communication.
• maps from the plateau of conformity and interoperability.
• Third, the rapid development of applications, the interaction with various suppliers.
• Third adding functions with high availability.Read more information by clicking the links below:

Music Blog | City Travel | Love Blog | Internet Nerds | Granaditas | Maldigras | About Cars | Nerve Crack | Gamer’s World | Perfect Diapason |  Anime | Latest Buzz | Business | Creative Innovations | Sports Reviews | Creative Writing | Fashion Today | Blog Loan Online | Online Opportunities | Blog Addict | Site Submission | Make Money Online | Technology | Gadgets | Articles | Gizmos | Travel | Finance | Blogging | Opinions | Entertainment | Reviews | Websites | Money | Sugar Free Blog | Bonsang | Latest Videos | Globe Auto Load | Airsoft | BlogToMillion | Lifestyle | Shopping | Computer | Britney Spears | PC Games | Marketing | News | Web Design | Society | Benefits | Services | Papable | Blog | Internet Marketing | Real Estate | Earn Online | jSison |