Rheid Communications

Broadband poses some real challenges to obtaining a reliable VoIP experience

• The asynchronous nature of ADSL means that there is much lower bandwidth upstream when compared to down. Since voice calls are by their very nature symmetrical in terms of bandwidth requirements, the number of simultaneous conversations that can be maintained is limited by the much slower upload speed ( typically 256Kbit/s. )
• Voice information can be compressed ( using similar techniques to MP3 music compression ) to use only 8kbit/s per call. However, due to the way in which it is packaged to be sent over a broadband network, the reality is that each call will use at least 42kbit/s – significantly higher.
• In order to allow voice and data to share the same network, QoS has to be employed. Standard QoS techniques do not work very well for voice carried over links with less than about 1000Kbit/s, and are not ideal even well above that. The effect of this is that voice information gets delayed because it has to wait for a free slot on the link in order to be sent – since peoples voices do not generally incorporate such delays this causes issues with voice quality.
• In addition, standard QoS techniques can not allocate more than 70% of the available link bandwidth reliably. This means that on a standard broadband link, three calls is the absolute maximum that can sensibly be achieved, and the quality of those calls will still suffer where data is present.
• On a standard ADSL broadband link, no QoS can be applied in the download direction.
• Broadband is usually part of a public or at least shared network, making security a concern.

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ViBE solves these problems in several important ways

• Quality of Service is implemented in a completely different way to traditional methods, being much more suited to slower links.
• Voice is no longer treated as simply another type of data which happens to have a high priority. Instead, it is treated as a data stream with very specific requirements not only in terms of priority, but also in terms of spacing between packets.
• The bandwidth budget required is reduced to that of the compression format used, so that a G.729 call really does only use 8Kbit/s over the ADSL link rather than the 42Kbit/s which is more usual. Rather than a maximum of three calls, twenty-eight calls are now practical on a single broadband line.
• Voice and data can readily coexist on a single link. Data transfer rates are not compromised by the fact that voice is present. Classes of data can be given their own share of available bandwidth in a much more granular way than traditional QoS.
• Sites that have Vibe links can be joined together to form private networks, which means that security is easier to control.
• Backup links can be implemented which can be activated without losing calls in progress.
• Much more of the capacity of the link can be used.
• Future development of the technology will allow multiple links to be used as a single large bandwidth connection, offering a viable alternative to costly private circuits.

  Download a PDF overview of how ViBE works and how ViBE can help you.

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Using only two ADSL lines upto 100 concurrent calls becomes a reality

The number of concurrent calls is dependent on both the line speed (available bandwidth in both directions) and the actual router used. The ViBE enabled NetGear DG834GT ADSL router can support a maximum of 30 concurrent calls before it starts to run out of resources. For more concurrency, the larger ViBE routers allow from 100 to 1000 concurrent calls, and can be used with most forms of connectivity including leased lines, satellite links and wireless technology.

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Key benefits of using ViBE

• Enables delivery of SIP trunking up to 28 ports on a single ADSL connection with only 256k upstream bandwidth, making it a replacement offering for E1 / T1 circuits
• Built in switch over to secondary IP connectivity enables resilient services to be deployed
• QOS and resiliency options enable delivery of chargeable SLA's
• Dynamic and seamless blending of Voice and Data using QOS allowing FULL utilisation of all purchased bandwidth increasing overall throughput for both voice and data traffic.
• Enables low Broadband bandwidth to be used for VPN connectivity in branch / retail environments offering simultaneous Voice and Data access eliminating need for expensive network alternatives or multiple connections
• Enables greater density of Centrex / Hosted sets per broadband or other circuit resulting in cheaper deployment costs.
• Improves user experience increasing rate of adoption
• Dynamic compression if required for voice traffic
• Supports multiple Voice protocols
• User benefits
• Business quality voice traffic on IP
• Savings by using a single circuit for both Voice and Data traffic
• Overall a better user experience
• Increased security for both voice and data traffic

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ViBE for Business

In a Point to Point scenario, a ViBE CPE device is installed at each location and is able to support up to 100 concurrent calls (G729a) on a 2mb circuit while still supporting data. Smaller devices are available for link speeds of 256k,512k or 1mb if required. For multi-site networks, a larger server device can be installed at the central site to service many remote CPE units. This type of deployment is sized on number of devices and concurrency of calls. Learn more about ViBE for Business.

ViBE for Service Providers

For ViBE to be deployed in a service providers infrastructure there are two seperate elements. The CPE which consists of a small footprint, diskless PC with dual LAN ports. This device sits between the DSL router and the LAN switch and captures all traffic. The device simply strips out all repetitive data before sending the payload to the router in as small a size as possible. In the core of the network, a Server based platform (or multiple platforms if resilience is required) is deployed to rebuild the traffic and deliver it on to its destination. This may be another Vibe link as part of a private network, an IP telephony provider or any form of data to any internet location. Learn more about ViBE for Service Providers.

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