Monday, April 16, 2012

VoIP providers should provide you an emergency calling

Honourable like with any be biased, when something becomes dominant to the masses, others pass on

wish for to arise and contend for the notice. The done has happened to VoIP technology. There are divers

VoIP providers out there already and it muscle be sturdy for some to on which one to go with. After all,

it's not objective the skill to name phone calls upward of the Internet that you prerequisite per Se. You

also lust after importance and convenience, lot other things. Unloose calls are being provided by a lot

of VoIP providers already, if not all, representation it as a less prominent banker to mull over

nowadays. Characteristic of work, extent, is what you should chief and prime look for. You don't long

for your phone calls to press lots of curriculum vitae rumble or for them to be oftentimes rambling.

You destitution a pure uncover and if it a day gets unconnected it would be

because of power folding.

For businesses that give birth to purchaser hot lines, this can kill the bung of their PBX (privileged office switch) methodology, to providing a increase in awake superiority which hand down solidly affect callers and recipients similar to one another.

 VIP review. Getting in whiff with cosmopolitan clients can be done via at liberty calls too with incontrovertible VIP providers, and network coverage won't be an release at all as the railroad runs in all respects the Internet. It's unequivocally entirely a circle can cut down on their expenses without having to Christian religion oblation the worth of their products or services.

Growing with any one of today's Prue-eminent VoIP providers would not barely hands distend receipts but also benefit the distinction of communication both within the following and to customers.

For unruffled tournament of a function with an aim to develop in the prehistoric years, it is leading these days to opt for the transaction VIP services. Such professional care has the gauzy aptitude to deter the job expanding all the over and over again. They are cheaper and give up with multiple benefits from the paramount help providers. The transaction VIP is to a large practiced these days aiding wee companies to behoove more prolific in a pithy carve out of tempo.

The greatest professional care providers of the transaction VoIP services from designed it as one alcohol and put billion VoIP, a proper design for the on one's own customers and multi alcohol VIP in which a on the cards tally of employees are masterful to create tie with each other.


Sunday, April 15, 2012

PartitionTraffic For VoIP

IP telephony is a method of revising voice signals into digital IP packets and sending it through cyberspace to the final destination. Bandwidth partitioning for digital packets can be done dynamically. As users get active in traffic class, sub-partitions are created on the fly.

Everything has been changing in the Telecommunications industry in the past few years except one – Innovation. It has enforced conceptualization and implementation of ideas, one after the other. Successful implementation of one idea has led to the advantageous enforcement of another. The trend continues and who knows what we are going to see in future.

IP Telephony is one of the big ideas that have left a huge imprint in the industry. Popularly known as VIP (Voice over Internet Protocol), it is a method of revising voice signals into digital IP packets and sending it through cyberspace to the final destination. A cost effective method of communication, VIP technology is fast advancing. As it runs on server, it can be integrated with other applications, bringing in a host of other lucrative benefits.

Digital Void packets, sent via the Internet, require a certain amount of bandwidth in order for the transmission quality to be acceptable. Traffic partition for the Void class manages the aggregate traffic and the concurrent flows for the class.

 The partition is combined with a rate policy which defines a minimum rate for each flow. This ensures that VoIP always has enough bandwidth to support the multiple flows during a session. In absence of this reserved chunk of bandwidth, the conversation would be choppy.

Bandwidth can be assigned to digital packets dynamically. As users get active in traffic class, sub-partitions are created on the fly. This technology allows service providers the ensure for users a minimum amount of bandwidth at all times. This strategy is efficient when a small number of users will be active in any given time period. For instance, a service provider has 30,000 customers with a couple of thousand users logged on at a given time.

With dynamic partition technology, sub partitions are automatically created for users as they log on. To accommodate new users when the upper limit is reached, the older non-active sub partition is removed releasing the bandwidth for active users.

You can also create static partitions. This kind of partition allows an aggregate traffic class to use a defined amount of bandwidth. Static partition ensures a specific amount of bandwidth for every digital packet and limits traffic to the same level. There is one more option called a bur stable partition. It allows an aggregate traffic class to use a defined amount of bandwidth, and to access additional unused bandwidth, if required.

All partitions are hierarchical, which means that partitions can contain sub partitions. The approach enables application management for multiple groups, which can be controlled as a whole. For instance, a service provider can allocate different amounts of bandwidth for a particular application to various user groups. The basic concept for hierarchical partitions is that child partition minimums are limited to the parent partition. When the sum of the child partitions exceeds the minimum size of the parent partition, the child partitions are scaled proportionately.

For information regarding how to switch partitions, it is advisable to consult a VoIP technology expert. They have expertise in Hosted / Partitioned Soft switch technology, well versed with VIP interconnection of gateways and switching.

Friday, April 13, 2012

Move Ahead - Using VoIP Termination in Business

VoIP offers a slew of advantages to organizations, making the technology a hot favorite in business circles and helping them condition their network according to the demands of today's business needs. However, they need to hire the right VoIP service provider to attain their objectives.

VoIP has turned over the predictions of many a communication industry pundit head on who initially put forth the view that it will never become the front line mode of communication. Today, all industry sectors are gradually moving to business VoIP from the conventional PS TN (Public Switch Telephony Network) system. The shift has taken its time, but it is decisive.

VoIP based communication not just helps the businesses bring their telephony bills down, but also improves the way they function in the today's competitive scenario. It offers a slew of advantages to organizations, making the technology a hot favorite in business circles. It helps them condition their network according to the demands of today's business needs. An organization which lags behind in implementing the technology finds pulling itself hard in the rat race with the competitors.

VoIP enables features such as Instant Chatting in accelerating business cycles and promote collaborative team culture. Many a time, people prefer Instant Messaging to phone. Web based conferencing is another mode of communication powered by VoIP. Conferences have become an integral part of any business whether it is big or small. It offers the option of video conference with a group of people located all across the world, thus negating any need to fly across thousands of miles just to attend a business meeting.

Conventional PSTN networks cannot support such modes of communication. Additionally, with VoIP technology, users can opt for DID numbers that are ideal for organizations which are operating from different countries. It gets them to get international phone calls from overseas customers without their customers being aware of the fact as they are charged locally for it. The service is particularly beneficial for call centers as they need to provide customer service to people residing in other countries.

'Click to Call' option provided on several websites is also an example of VoIP powered services. VoIP call termination integrates the Internet with the phone call enabling the system. It shows how the technology merges voice and data networks. It enables business organizations to immediately connect to their clients. It also helps in raising customer satisfaction, which is something every business strives for.

Business houses have emerged as the final winner, thanks to the evolution of VoIP. However, for reaping the benefits, subscription to a VoIP service provider is necessary. You can subscribe to retail VoIP service providers who are themselves associated with wholesale VoIP carrier services. While a retail operator will be providing services to the end customers, it is the wholesale provider who provides the network infrastructure, software and technical team which makes the operations possible.

A robust VoIP network will ensure excellent technical operations, flawless exchange of data and non-interrupted service availability. Their technicians keep constant tab on the network and do the troubleshooting if required. In fact, quality of a retail operator depends of the wholesale VoIP operator behind it. If a retailer is backed by a reputable wholesale carrier, you can expect that he will be providing reliable services.

Tuesday, April 10, 2012

Quality VoIP of Service VOIP SERVICE

This section aims to explain some of the issues that should be considered when planning a VoIP installation or prior to the installation. It should be noted that this section contains a general view of VoIP implementation. IP is today wide used for Voice Video Data purpose
VoIP Quality of Service: (OS) is one of the most important factors for VoIP. The term refers to the perceived quality of speech and the methods used to provide good quality speech transmission since voice is real time application. There are several factors that affect speech quality, and several mechanisms that can be used to ensure OS.

This section describes the problems that can occur and some possible solutions. Each network equipment manufacturer will have slightly different methods of implementing OS and these are not discussed in this document. This is just to give an overview and to explain how we can classify voice traffic so that the network equipment can impose OS.

What is Latency: Latency is delay, if at any point the usagee on the network exceeds the available bandwidth, the users will experience delay, also know as latency. In more traditional uses of an IP data network, the applications can deal with this latency. If a person is waiting for a web page to download, they will accept a certain amount of wait time. This is not applicable for voice traffic. Voice is a real time application, which is sensitive to latency.

If the end-to-end voice latency becomes too long (>250 ms, for example), the call quality would usually be considered to be poor. Another important thing to remember is that packets can get lost. IP is a best effort networking protocol. This means the network will try its best to get your information there, but there is no guarantee.

Delay is the time required for a signal to traverse the network. In a telephony context, end-to-end delay is the time required for a signal generated at the talker's mouth to reach the listener's ear. Therefore end-to-end delay is the sum of all the delays at the different network devices and across the network links through which voice traffic passes. Many factors contribute to end-to-end delay.The buffering, queuing, and switching or routing delay of IP routers primarily determines IP network delay. Specifically, IP network delay is comprised of the following.

Packet Capture Delay: Packet capture delay is the time required to receive the entire packet before processing and forwarding it through the router. This delay is determined by the packet length and transmission speed. Using short packets over high-speed networks can easily shorten the delay but potentially decrease network efficiency.

Switching/Routing Delay:
Switching/routing delay is the time the router takes to switch the packet. This time is needed to analyze the packet header, check the routing table, and route the packet to the output port. This delay depends on the architecture of the switches/routers and the size of the routing table.

Queuing Time:
Due to the statistical multiplexing nature of IP networks and to the asynchronous nature of packet arrivals, some queuing, thus delay, is required at the input and output ports of a packet switch. This delay is a function of the traffic load on a packet switch, the length of the packets and the statistical distribution over the ports. Designing very large router and link capacities can reduce but not completely eliminate this delay.
Jitter:
Delay variation is the difference in delay exhibited by different packets that are part of the same traffic flow high frequency delay variation is known as jitter. Jitter is caused primarily by differences in queue wait times for consecutive packets in a flow, and is the most significant issue for OS. Certain traffic types-especially real-time traffic such as voice, are very intolerant of jitter. Differences in packet arrival times cause choppiness in the voice.
All transport systems exhibit some jitter. As long as jitter falls within defined tolerances, it does not impact service quality.

 Excessive jitter can be overcome by buffering, but this increases delay, which can cause other problems. With intelligent discard mechanisms, IP telephony/VoIP systems will try to synchronize a communication flow by selective packet discard, in an effort to avoid the "warlike-talkie" phenomenon caused when two sides of a conversation have significant latency.
Packet Loss:
During a voice transmission, loss of multiple bits or packets of stream may cause an audible pop that will become annoying to the user. In a data transmission, loss of a single bit or multiple packets of information is almost never noticed by users. If packet drops become epidemic, then the quality of all transmissions degrades. Packet loss rate must be less than 5% for minimum quality and less than 1% for toll quality.
Voice Quality Improvements:
There are various techniques that can be used to improve the voice quality, including:

a) Increase the available bandwidth
This can sometimes be the most basic solution and the easiest of the solutions. If someone is running a IP Phone using G.711 with a 30ms fill time over Ethernet, for only one call, they need 83.7Kbps worth of bandwidth. If that same user only has a 64K line, they are not going to be able to have a decent IP voice call. The user can simply increase the available bandwidth to slightly exceed the 83.7Kbps requirements and their voice quality will dramatically increase. This solution might not be viable if no more bandwidth is available.

b) Use a different CO DEC
The CO DEC contains possible compression algorithms to be used on the voice. Lets take the example above again. The user only wants one voice line over a 64Kbps data connection. They also want to maintain their current fill time of 30ms. So, lets change to a G.729. Now for one line, only 27.7Kbps is required for a call. This fits well within the 64Kbps of available bandwidth.

c) Increase the number of frames per packet
To continue with the example above, the user has moved to a G.729 CO DEC. But now, the user wishes to add two more IP Phones. Their current 64Kbps line can handle one call, because it is only 27.7Kbps. Two more IP Phones would increase the total to 83.1Kbps so obviously there is not sufficient bandwidth.
The user can now increase the fill time to 50ms. This would then reduce the bandwidth per call to 19.8Kbps (3x 19.8 = 59.4Kbps). The savings in bandwidth comes from the fact that with a longer fill time, fewer packets are needed to send the voice. With fewer packets there is less header information that needs to be attached and transmitted.

d) Change Layer 2 Protocols
Ethernet is most commonly used for IP packets. Unfortunately Ethernet has a fairly large overhead of 34 bytes. So every IP voice packet going over Ethernet is going to have a 34 byte Ethernet header attached to it. As the number of packets add up, this amount of header data can become significant. Frame Relay has a 7-byte header and Point-to-Point Protocol (PP) has a 6-byte header. With this decrease in header length at layer 2, some significant savings in bandwidth use can be achieved.
The down side to this is that most networks may not have these services available, where Ethernet is very widely used. This is usually outside the control of the installer and therefore we need to do more research on other layer 2 protocols before trying to implement them in their voice network.

e) Implement Quality of Service (COS)
Now, assume a derivative of the above example. The user needs only one voice line over their 64Kbps connection. They are using G.729 with a 30ms fill time. This will require 27.7Kbps of their available bandwidth. Let us now also assume that this line is used at certain times of the day for data connectivity. This data connectivity is very light, only 20 Bps or so during most of the day, but does spike to 50 Bps during certain points of the day. This data is not time sensitive like the voice data, so if necessary it could be forced to wait.

Therefore the user can implement a Quality of Service mechanism on the IP network. At its most basic form, this denotes certain IP packets as being more important than others. So they would tell this 64Kbps line that IP packets with voice deserve a higher priority than those without voice. This would allow the network devices to give priority to the other data, so the quality of the call will not be compromised.

Classification of Traffic for OS:
Classification uses information from a packet (or frame) to define the type of data and therefore how the data should be handled for OS on the network. Using packet classification, you can partition network traffic into multiple priority levels or Types of Service (Toes).

CLAN (802.1Q):
Virtual Lanes work at Layer 2 of the OS model and can be equated to a "broadcast domain". More specifically, Clans can be seen as a group of end stations, perhaps on multiple physical LAN segments that are not constrained by their physical location and therefore, communicate as if they were on a common LAN. Packets can be marked as important by using layer 2 classes of service (Cos) settings in the User Priority bits of the 802.1Pq header.

IP Precedence - Layer 3 OS:
Allows you to specify the class of service for a packet. You use the 3 precedence bits in the Ipv4 header's type of service (Toes) field for this purpose. Using the Toes bits, you can define up to 6 classes of service. Other devices configured throughout the network can then use these bits to determine how to treat the packet in regard to the type of service to grant it. These other OS features can assign appropriate traffic-handling policies including congestion management and bandwidth allocation. By setting IP Precedence levels on incoming traffic and using them in combination with OS queuing features, you can create differentiated service.

Differentiated service (Diffuser) - Layer 3 OS:
Provides services differentiated on performance utilising weighted priority queuing. Diff-Servo requires that edge routers classify traffic flows into a member from a set of categories based upon the TC/IP header fields in what is called a micro flow. Because the Diffusers is present in every packet header, each node can provide differentiated services on a per-hop basis.

Monday, April 9, 2012

H.323 Voip Definition

H.323 standard is defined by the International Telecommunication Union (IT), which states that the protocols to provide audio-visual communication sessions on packet switched network.

The H.323 standard addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences.

It is widely implemented by voice and videoconferencing equipment manufacturers, is used within various Internet real-time applications such as VoIP, Video conferencing over IP.

H.323 is now considered to be the standard for interoperability in audio, video and data transmissions as well as Internet phone and voice-over-IP because it addresses call control and management for both point-to-point and multi point conferences as well as gateway administration of media traffic, bandwidth and user participation.
What are H.323 Components?
Terminals are the client endpoints on the LAN that provide real-time bidirectional multimedia communications. An H.323 terminal can either be a personal computer (PC) or a stand-alone device, running an H.323 stack and the multimedia applications.

It supports audio, video and data communications. H.323 specifies the modes of operation required for different audio, video and/or data terminals to work together.

H.323 terminal plays a key role in IP-telephony services, and is the dominant standard of the next generation of Internet phones, audio conferencing terminals, and video conferencing technologies.
Gateways
A gateway connects two or more networks. An H.323 gateway provides connectivity between an H.323 network and a non-H.323 network.

For example, a gateway can connect and provide communication between an H.323 terminal and TAM networks (Time Division Multiplexing networks include all switched telephony networks, e.g., PBX, public switched telephone network [PS TN]).

The connectivity of dissimilar networks is achieved by translating protocols for call setup and release, converting media formats between different networks, and transferring information between the networks connected by the gateway.

For example, in the case of video conferencing a gateway may be required to call H.323 end point or VIC in remote site and also to call a VIC in remote end point on ISBN.  Basically gateways convert TIM traffic to IP packets.

Gatekeepers
The gatekeeper is the most important H.323 components. The gatekeeper's primary job is to act as the central point for all calls within its zone and provide call control services for registered H.323 endpoints.

Basic function of the gatekeeper is address translation, Calls originating within an H.323 network may use an alias to address the destination terminal. Calls originating outside the H.323 network and received by a gateway may use an E.164 telephone number to address the destination terminal.

The gatekeeper must be able to translate the alias or the E.164 telephone number into the network address for the destination terminal. The destination endpoint can be reached using the network address on the H.323 network. The translation is done using a translation table that is updated with Registration messages.

For example in Voice over IP which is driving voice traffic over IP network, we dial the extension number of the remote IP phone. IP network only handles IP not decimal numbers, because we cannot remember IP address of remote equipment we are dialing by number.

This conversion of decimal numbers to IP address and IP address to decimal number is done by gatekeeper. Besides these function gatekeeper also does Admission Control, Bandwidth Control, and Zone Management.