Broadband & VoIP

VoIP strives on bandwidth. Lower the bandwidth, lower the VoIP quality. Broadband suits well for the growth of VoIP. Let us see briefly what Broadband is all about.

What is Broadband?

It is simply high speed Internet access. The broadband service allows 256 Kilobits per second onwards and can handle up to several Million bits per second data transfer. As the Broadband can handle large bandwidth, the users can enjoy high quality Internet services including streaming media, VoIP (Internet phone), interactive services and games.

Traditional dialup networking used to block the telephone line as long as the modem is connected to the internet. In the case of Broadband, the phone line is not blocked and the Broadband is always on and there is less delay in transmission of content.

Broadband Communications Services

Broadband opened up a new avenue to provide access to new telecommunications technologies. One such benefactor is Voice over Internet Protocol (VoIP) which provides voice communication using the Internet.

Broadband includes several high-speed transmission technologies like Digital Subscriber Line (DSL), Cable Modem, Fiber, Wireless, Satellite, Broadband over Powerlines (BPL) etc.

Digital Subscriber Line (DSL)

DSL technology uses the traditional copper telephone lines which are working for so many years. Hence no additional investment, other than the Modem is required. DSL-based broadband can provide transmission speeds ranging from 128 Kbps to millions of bits per second (Mbps). DSL transmission can be either Asymmetrical or Symmetrical. Asymmetrical Digital Subscriber Line (ADSL) technology provides faster downloads and suits the users well who do not upload much data. Typical users of this are the residential customers. Symmetrical Digital Subscriber Line (SDSL) caters to people who need high bandwidth for upstream as well as downstream for Video conferencing etc. The business users, who want still higher transmission speeds may look for High-data-rate Digital Subscriber Line (HDSL) and Very High-data-rate Digital Subscriber Line (VDSL).

Cable Modem

Cable Television has been there for quite some time. To leverage this user base, Cable operators offer Cable modem service to provide broadband using the same coaxial cables that deliver Television transmission. The cable modem may have two connections, one to the cable wall outlet and the other to a computer. The transmission speeds may start from 1.5 Mbps onwards and subscribers can watch their regular TV Channels as well as login into the Internet

Fiber

Fiber optic technology converts data to light and sends through transparent glass fibers at speeds far exceeding DSL or cable modem speeds. Hence fiber optic cables suit the Broadband. The same fiber providing your broadband with Internet access can also simultaneously deliver VoIP and video services like video streaming and video-on-demand.

Wireless

Wireless broadband uses a radio link between the customer’s location and the service provider’s facility. Mobile or Fixed Wireless broadband can be provided by the service provider. A tower with an external antenna is usually provided by the ISP. This is extremely useful where cable laying is an issue.

Airports, Shopping complexes, Coffee shops and many other public locations now are installed with Fixed wireless broadband service. This allows the people to login into the Internet easily and many times, for free.

Mobile telephone service providers look for value addition to their clients and one of the regular feature is the Internet access through the mobile phones. A special card with a built in antenna is offered by the ISPs. One need to plug the card into the laptop and dial the ISP to go on to the Internet.

Satellite

Satellites are used extensively for telecom and entertainment industry like Television and Radio. Some satellites offer wireless broadband. This is very useful to provide Internet access to remote areas. Many Educational institutions are offered satellite broadband at concession tariff.

This service depends on the weather conditions and the connectivity may be lost in some extreme weather conditions. The bandwidth offered is lower as compared to DSL and cable modems.

Broadband over Powerline

This is a new technology. While DSL is aimed to leverage existing copper lines of telephone, Broadband over Powerline, as the name suggests, leverages the existing low and medium voltage electric power lines to deliver Broadband internet. This is still relatively new and we need to wait some more time to see this take off in a large scale.

VoIP & Broadband

With so many types of Broadband are available, you may choose which is appropriate and economical for you. If you use telephone extensively, you must look into VoIP and take advantage of Broadband. VoIP can save you a lot of money. One problem is that, if you depend on VoIP, you lose communication channel, if your broadband fails.

Service providers offer different plans for VoIP on broadband. One can select 500 minute outgoing or unlimited outgoing. And generally, for incoming VoIP calls, there is no limit. Many tariffs from $12.95 per month to $199 per year are available to choose from.

As indicated earlier, Broadband is required for VoIP to work. You may be residing in one area, but can opt for a different area code, say Texas, when you sign up. You will be supplied with an adapter. Once you connect the standard telephone, the adapter and the broadband, you are ready to make calls using VoIP. As you have the area code as that of Texas, any one calling from Texas to you (though you are in a different place), will be considered local calls.

Cable operators and DSL service providers are now able to offer VoIP to their existing residential customers and small business customers. This is a good value addition and the customers will find it very helpful, while the Cable operators and DSL service providers make some additional money.

Broadband –key to the future of VoIP

While different types of Internet connectivity are being exploited and the research is on for different way, Broadband is here to stay. While many move towards Wireless, still the backbone may be broadband.

In future we will be seeing and experiencing very high bandwidth Broadband and residential users will be benefited more as the VoIP equipment will bundle many applications and all they need to do is connect a phone ( either standard or VoIP) to the broadband.

Some Good books on VoIP

Switching to VoIP by Theodore Wallingford	Voice over IP Fundamentals by Jonathan Davidson, James Peters, and Brian Gracely	VoIP For Dummies (For Dummies (Computer/Tech)) by Timothy V. Kelly
VoIP Hacks: Tips & Tools for Internet Telephony (Hacks) by Ted Wallingford	Practical VoIP Security by Thomas Porter and Jan Kanclirz Jr.	SIP Beyond VoIP: The Next Step in the IP Communications Revolution by Henry Sinnreich, Alan B. Johnston, Robert J. Sparks, and Vinton G. Cerf
Taking Charge of Your VoIP Project by John Q. Walker and Jeffrey T. Hicks	Building a Voip Network with Nortel's Multimedia Communication Server 5100 by Larry Chafflin and Larry Chaffin	Softswitch : Architecture for VoIP (Professional Telecom) by Frank Ohrtman

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 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.