Types of VoIP Networks
The model for the next-generation network is evolving as the market for VoIP and other real-time, packet-based services is maturing. The session controllers play a critical role by enabling cost-efficient VoIP peering. They also play an important role in the delivery of advanced traffic-management capabilities across the network. They are also offering critical telephony functions such as VoIP call routing and billing.
The approach of leveraging softswitch and session-control technologies is to eliminate traditional scalability limitations and manageability issues. This also helps in spurring accelerated adoption of VoIP and other advanced services. Future developments must address Advanced IP Communications networks to interconnect as well as share network information with one another.
Some companies claim to have fifth-generation network with expertise in providing IP networks and VoIP solutions. Today the network companies offer appropriate solutions to the clients. For example one company that provides communications infrastructure can offer pure Advanced IP Communications network. The network can support Session Initiation Protocol (SIP), H.323, Media Gateway Control Protocol (MGCP), etc and offer a range of voice, data, video and multimedia applications, such as IP peering, hosted IP telephony (HIP-T), direct Internet access, data and voice virtual private networks, termination, toll-free and local origination, conferencing and voice mail. These could be used by all kind of customers including cable systems providers, wireless providers, Internet service providers, enterprises, multimedia companies and residences.
The VoIP networks have proved their maturity and can now processes more than a half billion VoIP calls per month. Generally the providers will have a MPLS backbone with a configuration that prevents service disruption through diverse routing and carrier-class redundancy. This level of quality is achieved by processing each and every session individually and applying a set of accurate and unique rules to each session.
As the customer base and protocol complexity expands, the Network providers must enhance their infrastructure with greater flexibility in order to keep their customer’s prices low and protect their own profit margins.
Several protocol-interoperability challenges arise due to the fact that different vendors interpret H.323 and SIP protocol recommendations for message format, timing and sequence in different ways. This creates limitations in interconnecting with various IP networks. The network provider shall come out with their method to overcome these limitations and maximize cost efficiencies by peering with virtually any other service provider, inside or outside the country. Additional traffic management capabilities are to be addressed to improve call-completion rates.
Session controllers
Softswitches represent an architecture change, whereby network control is no longer embedded in the hardware in a proprietary way. This softswitch-based architecture is open and distributed in nature. This allows service and control to be distributed. They need low investment and minimize cost of ownership and provide capabilities necessary to introduced advanced services.
Service providers need to look to both softswitches and session controllers to enable voice and other real-time services over IP and accommodate cost-effective network expansion. Softswitch technology takes care the cost efficiencies and functionality that service providers require to interconnect with the PSTN.
Session controllers deliver the advanced management functionality to overcome network security, signaling inter-working and multi-vendor interoperability issues. Session controllers take care of interconnection of SIP- and H.323-based networks via IP as well as enable a service provider to interconnect with carrier partners via VoIP peering.
Time Division Multiplexing (TDM) ports were used by service providers on media gateways to interface with other VoIP carriers. Digital signal processors (DSPs) on media gateways linked back to back, in TDM peering, convert voice traffic from VoIP to TDM and back to VoIP again at the edge of the network. However, in VoIP peering, the service provider converts voice traffic to TDM only when it originates or terminates calls on the PSTN.
The session controllers enable network to route and manage authorized traffic to optimum peering points, resulting in a more scalable network, delivering improved call-completion rates.
Service providers can achieve profitability with wide-scale deployment of VoIP by controlling the network border and efficiently routing and managing real-time sessions across their IP networks. End-to-end session control has a critical role in the evolving model for next-generation networks.
VoIP Network Components
The components of a VoIP network are similar in functionality to those of a circuit-switched network. VoIP networks must perform all of the same tasks that the PSTN does apart from performing a gateway function to the existing public network.
There are three major pieces to a VoIP network.
• Media gateways
• Media gateway/signaling controllers
• IP network
Media Gateways
Media gateways are responsible for call origination, call detection, analog-to-digital conversion of voice, and creation of voice packets. Media gateways also have optional features, such as analog and/or digital voice compression, echo cancellation, silence suppression, and statistics gathering.
Typically, each conversation is a single IP session transported by a Real-time Transport Protocol that runs over UDP. Media gateways exist in several forms like a dedicated telecommunication equipment chassis, or even generic PC running VoIP software. Media Gateways may have features and services as below:
Residential gateways - To provide a traditional analog interface to a VoIP network like cable modem/cable set-top boxes, xDSL devices, and broadband wireless devices.
Access media gateways - to provide a traditional analog or digital PBX interface to a VoIP network, like small-scale enterprise VoIP gateways.
Trunking gateways - To interface between the telephone network and a VoIP network for typically managing a large number of digital circuits.
Business media gateways - to provide a traditional digital PBX interface or an integrated soft PBX interface to a VoIP network.
Media Gateway Controllers
Media gateway controllers are designed to house the signaling and control services that coordinate the media gateway functions. Media gateway controllers could be considered similar to that of H.323 gatekeepers and have the responsibility for some or all of the call signaling coordination, phone number translations, host lookup, resource management, and signaling gateway services to the PSTN. The functionality depends on the VoIP enabling products used.
You can breakup the role of a controller into signaling gateway controller and media gateway controller, in a scalable VoIP network. Only a media gateway controller is needed to complete calls for the calls that originate and terminate within the domain of the VoIP network. However, a VoIP network is frequently connected to the public network.
IP Network
VoIP network can be seen as one logical switch as a distributed system, rather than that of a single switch entity. The IP backbone provides the connectivity among the distributed elements in the network. The IP infrastructure shall take care of smooth delivery of the voice and signaling packets to the VoIP elements. The IP network must treat voice and data traffic differently. When an IP network carries voice and data traffic, the different traffic types must be able to be prioritized.
VoIP High Density Gateway System – some features
The approach of leveraging softswitch and session-control technologies is to eliminate traditional scalability limitations and manageability issues. This also helps in spurring accelerated adoption of VoIP and other advanced services. Future developments must address Advanced IP Communications networks to interconnect as well as share network information with one another.
Some companies claim to have fifth-generation network with expertise in providing IP networks and VoIP solutions. Today the network companies offer appropriate solutions to the clients. For example one company that provides communications infrastructure can offer pure Advanced IP Communications network. The network can support Session Initiation Protocol (SIP), H.323, Media Gateway Control Protocol (MGCP), etc and offer a range of voice, data, video and multimedia applications, such as IP peering, hosted IP telephony (HIP-T), direct Internet access, data and voice virtual private networks, termination, toll-free and local origination, conferencing and voice mail. These could be used by all kind of customers including cable systems providers, wireless providers, Internet service providers, enterprises, multimedia companies and residences.
The VoIP networks have proved their maturity and can now processes more than a half billion VoIP calls per month. Generally the providers will have a MPLS backbone with a configuration that prevents service disruption through diverse routing and carrier-class redundancy. This level of quality is achieved by processing each and every session individually and applying a set of accurate and unique rules to each session.
As the customer base and protocol complexity expands, the Network providers must enhance their infrastructure with greater flexibility in order to keep their customer’s prices low and protect their own profit margins.
Several protocol-interoperability challenges arise due to the fact that different vendors interpret H.323 and SIP protocol recommendations for message format, timing and sequence in different ways. This creates limitations in interconnecting with various IP networks. The network provider shall come out with their method to overcome these limitations and maximize cost efficiencies by peering with virtually any other service provider, inside or outside the country. Additional traffic management capabilities are to be addressed to improve call-completion rates.
Session controllers
Softswitches represent an architecture change, whereby network control is no longer embedded in the hardware in a proprietary way. This softswitch-based architecture is open and distributed in nature. This allows service and control to be distributed. They need low investment and minimize cost of ownership and provide capabilities necessary to introduced advanced services.
Service providers need to look to both softswitches and session controllers to enable voice and other real-time services over IP and accommodate cost-effective network expansion. Softswitch technology takes care the cost efficiencies and functionality that service providers require to interconnect with the PSTN.
Session controllers deliver the advanced management functionality to overcome network security, signaling inter-working and multi-vendor interoperability issues. Session controllers take care of interconnection of SIP- and H.323-based networks via IP as well as enable a service provider to interconnect with carrier partners via VoIP peering.
Time Division Multiplexing (TDM) ports were used by service providers on media gateways to interface with other VoIP carriers. Digital signal processors (DSPs) on media gateways linked back to back, in TDM peering, convert voice traffic from VoIP to TDM and back to VoIP again at the edge of the network. However, in VoIP peering, the service provider converts voice traffic to TDM only when it originates or terminates calls on the PSTN.
The session controllers enable network to route and manage authorized traffic to optimum peering points, resulting in a more scalable network, delivering improved call-completion rates.
Service providers can achieve profitability with wide-scale deployment of VoIP by controlling the network border and efficiently routing and managing real-time sessions across their IP networks. End-to-end session control has a critical role in the evolving model for next-generation networks.
VoIP Network Components
The components of a VoIP network are similar in functionality to those of a circuit-switched network. VoIP networks must perform all of the same tasks that the PSTN does apart from performing a gateway function to the existing public network.
There are three major pieces to a VoIP network.
• Media gateways
• Media gateway/signaling controllers
• IP network
Media Gateways
Media gateways are responsible for call origination, call detection, analog-to-digital conversion of voice, and creation of voice packets. Media gateways also have optional features, such as analog and/or digital voice compression, echo cancellation, silence suppression, and statistics gathering.
Typically, each conversation is a single IP session transported by a Real-time Transport Protocol that runs over UDP. Media gateways exist in several forms like a dedicated telecommunication equipment chassis, or even generic PC running VoIP software. Media Gateways may have features and services as below:
Residential gateways - To provide a traditional analog interface to a VoIP network like cable modem/cable set-top boxes, xDSL devices, and broadband wireless devices.
Access media gateways - to provide a traditional analog or digital PBX interface to a VoIP network, like small-scale enterprise VoIP gateways.
Trunking gateways - To interface between the telephone network and a VoIP network for typically managing a large number of digital circuits.
Business media gateways - to provide a traditional digital PBX interface or an integrated soft PBX interface to a VoIP network.
Media Gateway Controllers
Media gateway controllers are designed to house the signaling and control services that coordinate the media gateway functions. Media gateway controllers could be considered similar to that of H.323 gatekeepers and have the responsibility for some or all of the call signaling coordination, phone number translations, host lookup, resource management, and signaling gateway services to the PSTN. The functionality depends on the VoIP enabling products used.
You can breakup the role of a controller into signaling gateway controller and media gateway controller, in a scalable VoIP network. Only a media gateway controller is needed to complete calls for the calls that originate and terminate within the domain of the VoIP network. However, a VoIP network is frequently connected to the public network.
IP Network
VoIP network can be seen as one logical switch as a distributed system, rather than that of a single switch entity. The IP backbone provides the connectivity among the distributed elements in the network. The IP infrastructure shall take care of smooth delivery of the voice and signaling packets to the VoIP elements. The IP network must treat voice and data traffic differently. When an IP network carries voice and data traffic, the different traffic types must be able to be prioritized.
VoIP High Density Gateway System – some features
The VoIP Gateway is fully SIP and H.323 standard compliant residential gateway that provides a total solution for integrating voice-data network and PSTN. By simple installation, this revolutionary compact voice over IP (VoIP) gateway could be configured as 8 channels high density FXS/FXO VoIP Gateway which provides voice connectivity over the IP network and to the Public Switched Telephone Network (PSTN).The Gateway is equipped NAT router function that provides Internet access using only one IP address.
Besides, it provides high voice quality and optimized packet voice streaming over managed and public (Internet) IP networks.
The key features of a VoIP gateway are that support SIP and H.323 protocols: SIP Registration and Digest Authentication and H.323 Gatekeeper Registration. It has Polarity Reversal Detection: Type I and Type II
There is even NAT traversal: This feature allow gateway to operate behind any NAT/Firewall device. There is no need to change any configuration of NAT/Firewall like setting virtual server. Another important key feature is that it has Smart-QoS: This feature provides good voice quality when user place a VoIP call and access internet at the same time. The gateway will automatically start to reserve bandwidth for voice traffic when VoIP call proceeds. It also has Voice Channels status display: This function display each port status like as onhook, offhook, calling number callee’s number, talk duration, codec.
Future VoIP Network
VoIP can be deployed in many different network segments. So far, it has been mostly deployed in the backbone and enterprise networks. We need to address additional constraints for deploying VoIP as an end-to-end Next-Generation Network solution.
posted by rameshkumarb @ 12:35 AM
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