Broadband Satellite Internet VoIP Solution
Voice over Internet Protocol (VoIP) telephony is a technology taking
the world by storm. VoIP allows people to use their computer's
Internet connection as a telephone, resulting in huge savings on
both local and long distance calling. VoIP technology sends voice
transmissions over the Internet as a data packet, which is organized
and decoded by the VoIP software. Most people who receive a VoIP
call over their standard telephone line never even realize that they
are connected with a VoIP user. VoIP over satellite works just
like the telephone you have in your home today. You pick up the
phone, dial the number and it connects to whom you're calling
through your high-speed satellite internet connection.
With developments in Internet and IP networking, the ability to transmit voice calls which have been traditionally handled by the public switched telephone network (PSTN) over a lower cost IP infrastructure has become a reality. More and more users are researching VoIP capability when purchasing a connection to the Internet or simply expanding their private intranet. VoIP based telephony has also provided a very cost-effective solution for companies that have locations in many disparate regions and require connectivity back to their headquarters.
What are important elements, that require consideration, when engineering a satellite network capable of effectively handling VoIP? There are several of them:
There is approximately 280 msec of one-way propagation delay due to the location of the Geo Stationary orbit and the speed of light. Regardless of the satellite product, this propagation delay must be considered and overcome. Today, numerous overseas calls originated in the United States are actually transmitted as VoIP over satellite calls, particularly if provided by the smaller long distance carriers.
Quantifies the effects of network delays on packets arriving at the receiver. Packets transmitted at equal intervals from the transmitting gateway arrive at the receiving gateway at irregular intervals. Excessive jitter has the effect of making speech choppy and difficult to understand. Jitter is calculated based on the inter-arrival time of successive packets. For high-quality voice, the average inter-arrival time at the receiver should be nearly equal to the inter-packet gaps at the transmitter and the standard deviation should be low. Jitter buffers (packet buffers that hold incoming packets for a specified amount of time) are used to counteract the effects of network fluctuations and create a smooth packet flow at the receiving end.
Packet loss or packet corruption will cause degradation of voice quality. Since all of the voice traffic is UDP/IP and would not be retransmitted (like in the case of TCP/IP) all packets would be completely lost if the packet becomes lost or corrupted. It is extremely important to have very low Bit Error Rates (BER) to ensure low or no corruption or loss.
QoS and Traffic Prioritization
Packet switched networks are subject to congestion as typical data traffic is bursty. Congested networks can wreak havoc on a VoIP call with delayed , dropped , or packets that are out of sequence. It is a necessity to have QoS and Prioritization in order to guarantee delivery of VoIP traffic through congested links.
There are many encoding schemes that have been standardized for voice. The most dominant standard in the industry is the G.729 codec. G.729 encoding requires 8Kbps of bandwidth, but because of the overhead associated with IP/UDP/RTP headers, the actual bandwidth needed is between 16 and 18Kbps (depending on the equipment vendor and configuration). With Compress RTP (cRTP) the total bandwidth requirement per call will drop to about 10Kbps. There are other standards, such as G.723 that takes only 5.3Kbps for the voice payload.
Required bandwidth per VoIP call
To design a network properly, one would need to know the amount of bandwidth required per VoIP call, the number of concurrent calls, and the duration of the call. Bandwidth required per VoIP call will depend the encoding standard used, header compression, and payload size. For example, with G.729(b), payload of 40 bytes, and no header compression, a VoIP call would take about 16Kbps of bandwidth. With header compression this would require 10Kbps of bandwidth.
A pair of Internet phone providers recently signed deals to help satellite companies add Net-phoning service to their arsenal of offerings.
Hughes Electronics and voice over Internet Protocol (VoIP) provider Net2Phone announced an agreement this week to combine Hughes' satellite-delivered broadband service with Net2Phone's inexpensive dialing plans, which rely on the Internet rather than a phone company's privately owned network. The two companies are first targeting broadband- and phone-starved areas in Africa.
On Tuesday, New Jersey-based VoIP provider Vonage said it has a similar-sounding project in the works with satellite broadband service provider SkyFrames. The companies plan to make their combined services available to troops in Iraq during the upcoming holidays and, according to Vonage Executive Vice President Louis Holder, "could conceivably push this service out" to a wider audience, depending on its success.
Some believe that satellite companies and VoIP providers are a pairing made in heaven. The coupling enables the satellite providers to keep pace with rival cable companies, which are using VoIP to sell a "triple play" of broadband, television and telephone service. VoIP providers, for their part, get a chance to find new customers, and--in the case of Net2Phone--be the first telephone services in areas where traditional phone lines haven't yet reached, said Net2Phone Global Service President Bryan Wiener.
But the marriage of these two technologies is not without problems. Because VoIP calls use the Internet instead of traditional phone lines, the packets of digital information can get lost among trillions of other Net communications. The initial service with SkyFrames is "a little better than cellular, but a little worse than what we're used to," Holder said.
Net2Phone's Wiener said, however, that his company and Hughes have developed a way to prioritize voice calls, as they travel over networks. That helps ensure the high level of voice quality traditional phone dialers now expect, he said.
A SkyFrames representative didn't respond to a call seeking comment
In more technical terms, the VOIP system uses the phone adapter that we send to you for free to convert your voice from an analog signal to a digital signal. The digital signal then can be sent over your high speed Internet connection because it is recognized as data and then is sent over the Internet.
When someone calls you, they dial your number. Behind the scenes,
your number looks very much like an e-mail address. This number
instructs the call to travel over the Internet and through our
network to the phone adapter we sent you, your phone rings, and
all you have to do is pick up and answer it. All you need is a
high-speed Internet connection such as satellite internet. A
high-speed Satellite Internet connection is the connection to your
home that provides fast access to the Internet.
VOIP over Satellite introduction
Our 2-way satellite system do cover areas of the world where stable communication is quite difficult to get. Up to now we only have been able to deliver internet conectivity. It is quite obvious that also telephony is of extremely high interest to our customers. Thatßs why all our office solutions do have 2 VOIP Ports right from delivery.
The qualtiy which can be achievable over a satellite link can be compared quite well with the one over Immarsat or other satellite phones systems. Sometimes also with intercontinental calls, if they are not routed by optical fiber cable but by Satellite.
the VOIP gateway:
Our VOIP adaptor has 2 standard Voice Ports, which can be directly connected to a PSTN system or a regular analog telephone. Of course you also can use your cordeless phone. The adaptor is connected by Ethernet to our Performance Enhancement Gateway (PEH-Gateway).
does other VOIP equipment work on the satellite ?
We have tested many solutions, but only few
of them really have convinced our engineers. We have successfully
tested our equipment working with our satellites.
Are you sick of paying exorbitant amounts to call Wisconsin, Macedonia, or Middle East?
The new service is designed to
provide long distance IP voice services to remote and underserved
areas of the world, enabling end users to place calls anywhere in
the world at competitive prices. The end users are expected to be
enterprises, and providers of voice and data services to the public,
such as Internet cafes and kiosks.
Make voice calls while you surf
With DIRECWAY VoIP,
you can surf, send and receive emails, download files and make a
voice call, all at the same time.
iDirect technology provides an industry-leading solution allowing enterprises to design networks that simultaneously support data, voice, and video traffic. iDirect delivers unparalleled features and functionality which guarantees VoIP quality even through congested networks.
iDirect’s solution is capable of delivering BER better than 10-9 which is considered clear channel transmission and is therefore ideally suited for VoIP applications. iDirect provides its customers with a scalable private network solution where the QoS can be predefined and established. QoS can be assigned by traffic type, origination and destination, and can also be assigned a percentage of the bandwidth. In addition, available CIR (Committed Information Rate) capability allows the customer to plan the needed bandwidth in advance to make sure that all of the VoIP calls are of the highest quality.
iDirect’s platform supports H.323 or SIP compliant VoIP solutions thus allowing our customers the freedom to choose from multiple equipment vendors.http://idirect.qorvis.com/galleries/default-file/Voice_over_IP_VOIP_over_Satellite.pdf
VoIP technology continues to gain momentum and increasingly carries more traffic. as it proves to be a cost-effective method to implement and manage enterprise based voice solutions.. With new satellite technology the benefits of VoIP are further exacerbated by the tremendous flexibility, availability and reach inherent in a satellite transmission solution.
As with any solution, there are many issues to consider before deploying a VoIP solution. These include latency, reliability, traffic prioritization, QoS, and compatibility. The most of new Satellite Internet systems address all of these issues with a cost-effective, technically superior solution.