Terms
VON
Voice Over the Net. Voice transmitted over the Internet. That is the technical definition. Prescient Worldwide’s
product, called VON, means “Voice Over Network” – as in ANY network, whether a client’s private network, the Internet, a public network, and any combination thereof. We call it, “voice over anything”.
VoIP
Voice over Internet Protocol. Any “voice over” method that utilizes the IP packet set.
The difference between these two is Von is a subset of VOIP. Today, most vendors deliver VOIP as a “point-to-point”
protocol, either logically or physically, on a proprietary infrastructure. Voice over the Network is delivered over the Internet. Thus, we are not establishing point-to-point infrastructure, but are using the existing infrastructure of the Internet to deliver that voice traffic. Why is that? Which method is better? Well, while multiple sound arguments could certainly be made on any “side” of that question, the true-est answer is “it depends”. From our perspective, it is irrefutable that the Internet represents the most robust and multi-redundant network on the planet. Therefore, if we can utilize that network in a manner that enables us to also control how our traffic is “treated” within the net, we have truly accomplished the best of both worlds, and we truly have something very special. In fact, that is exactly what our product, called VON, is all about.
LAN
Local Area Network. A communications network connecting personal computers, workstations, file servers, printers, and other devices inside a building or a campus. Devices on a LAN can transmit between each other, so one PC can send another a file. A PC can print to any of the printers connected to the network and so forth. There are many types of LANs but by far the post popular is Ethernet. 99 times out of 100, if someone says they have a “computer network”, they have an “Ethernet LAN”. If you want this LAN to be able to connect with other LANS, then you would connect it to a telecommunications circuit of some type to make that connection. That connection would be called a “WAN”.
WAN
Wide Area Network. LANs connected via a communications circuit or link of some kind.
CODEC
Stands for COder/DECoder, or COmpression/DECompression, depending upon who you talk to. A CODEC takes sound, in it’s natural form as an analog sound wave (like when it leaves your mouth) and converts it into a digital signal so that it can be transmitted across a network. Then, it takes that digital signal and transforms it back into an analog sound wave so that your ears can hear it. In today’s world of “digital voice” there are two primary types of CODECS in use:
729 – A compression codec that compresses the voice signal to a digital stream that is 8kbps of bandwidth in size. In practice, with the various other data that must be sent along with the voice stream (called “overhead”) the band width required is actually about 20kbps.
711 – The same as above, except that the voice signal is encoded to 64kbps, and with overhead actually requires about 80kbps.
Terms
ATM
Asynchronous Transfer Mode. A very high speed transmission technology. ATM is high bandwidth, low delay, and connection oriented. It has been the standard for many years for signaling among the core of carrier networks and the Internet core. To explain in simple terms, think of a railroad that connects all of the places people and cargo may need to go. If you set it up so that every train has 10 cars and the trains run in both directions at all times, then if there are more than 10 cars worth of passengers, some will need to wait. In telecommunications, waiting equals lost data, or a disconnected voice call. Not good. Since ATM is Asynchronous, that means that it does not necessarily run the same amount of capacity in both directions at all times, like the railroad above, but instead will run whatever number of trains in a given direction that are necessary to ensure that all the passengers get where they need to go without waiting.
Frame Relay
Frame Relay is a data transmission protocol. It gets its name because it places data, and the information required to transmit it properly, into a “frame” that is made up of several fields. It places the data to be transmitted into a specific field, surrounded by four other fields, which contain information about where the data frame should go and how it should be handled. A user installs dedicated circuits to connect its locations to the Frame Relay network of their carrier.
Then, the carrier utilizes what’s known as “Permanent Virtual Circuits” or “PVCs” to transmit the data within the network. The main advantage of Frame Relay is that it enables you to only need one connection from each site to enable you to be linked to all sites. For example, if I have 4 offices that all need to be connected to each other (called a
“meshed” network”), I would need 6 circuits. But, with frame relay, I need only 4. Frame Relay enables me to do that job with 1/3 fewer circuits. Plus, there are other advantages as well such as network reliability, ability to only pay for higher speeds when I need them, etc. When buying Frame Relay, the client pays for the local circuits to connect it to the carrier, and then pays for the PVCs and the traffic it sends over them. There are various pricing methods used by the various carriers for this.
SIP
Session Initiation Protocol. An application layer protocol for the establishment, modification, and termination of conferencing and telephony sessions over an IP-based network. SIP uses text-based messages, much like HTTP. SIP does a great many things, and makes a great many things possible. For example, if you use a device (PC or other
network-connected appliance) to initiate a videoconference, SIP would contact the other devices you want to connect to, and would negotiate how the conference will take place. SIP will find a common set of protocols for the audio and video transmission – which may end up being ones that are NOT what any of the users actually have independently. SIP will determine if everyone has whiteboarding capability, and if so will enable that feature. Prescient Worldwide is a true SIP carrier, and our VON service uses SIP, as does most of our VON equipment that we offer. Many VOIP service providers do not actually provide SIP-based lines or services.
Terms
QoS
Quality of Service. Determines how a stream of data is handled, and prioritized, within a network. For example, one might set their network to always prioritize voice traffic. In such a case, at times when lots of people are on the phone, the speed of their computer Internet connections will drop. This refers to activities taking place within a user’s internal network (LAN).
CoS
Class of Service. Class of Service means several different things in telecommunications. In today’s telecom world, the primary use of this term is to refer to the numerical “values” that are assigned to types of traffic within a network for the purpose of accomplishing QoS. For example a “1” may be the Cos value that indicates highest priority traffic.
Diffserv
Differentiated Services. This is basically QoS within a carrier’s network. In other words, for a fee, a carrier could offer a client the guarantee that their critical data traffic (or voice) will be prioritized over other types of traffic.
MPLS
Multi Protocol Label Switching. In simple terms, MPLS allows you to designate a path from a-c, allows you to set QoS from a to c, and allows you to set security from a to c. It is the most easily implemented and managed platform for multi-services networks. Here’s the complete definition: Multiprotocol Label Switching (MPLS) is a development by the Internet community. It seeks to combine the flexibility of the IP network layer with the benefits conferred by a
connection-oriented approach to networking. MPLS, like Frame Relay, is a label-switched system that can carry multiple network layer protocols. Similar to Frame Relay, MPLS sends information over a wide area network (WAN) in frames or packets. Each frame/packet is labeled and the network uses the label to decide the destination of the frame. In an MPLS network we can define explicit paths or let IP routing decide the path. MPLS networks can use Frame Relay, ATM and PPP as the link layer. A key feature is to separate network control and data forwarding. This makes MPLS extensible to many environments including SDH and Optical networks
POTS
Plain Old Telephone Service. Refers to traditional dial-tone lines at a home or business.
Router
Routers connect like and unlike LANs, providing an interface between the two networks. Today, routers are typically highly intelligent devices that perform very sophisticated “treatment” and “traffic management” of the data that they route. They perform these functions by using “routing tables” that are pre-programmed, and/or user programmed, to establish and maintain these “rules of the road” that they employ in performing their tasks.
Terms
POE
Power Over Ethernet. POTS service provides power to the telephone devices plugged into it, such as the phone your mom had on the wall in the kitchen. That did not need to be plugged into an electrical outlet. Further, traditional PBX phone systems also provide power to the telephones plugged into them via the telephone system wiring. In VOIP/VON phone systems, therefore, we must either plug each end-device (such as a phone) into an electrical outlet, or inject power into the LAN cabling (typically CAT-5e cable). There are simple devices that accomplish this. Prescient Worldwide often employs a special type of Router that also gives the client their POE capability as well.
Switches and Hubs
A hub is simply like a rotary, where multiple roads come together, but there are no stop signs, traffic lights, or traffic cops. It is simply a place where traffic can physically get from one path to another. A Switch adds traffic lights to that example, so that traffic is directed to different paths based upon where it is trying to go. To continue this example, a Router would be like adding a traffic cop to the situation, thus providing a much more sophisticated level of intelligence that will utilize different actions depending upon the various traffic situations that arise at different times, such as stopping all traffic to allow an ambulance through, or re-directing traffic that would normally go a certain route to a different route because there is an accident ahead.
OSI Model
ISI stands for Open Systems Interconnection. It is the only internationally accepted framework of standards for
communication between different systems made by different vendors. Most of the dominant communications protocols used today have a structure based on the OSI model. The OSI model organizes the communications process into seven different categories, and places these categories in a layered sequence based on their relations to the user. Layers 7 through 4 deal with end-to-end communications between the message source and the message destination, while layers 3 through 1 deal with network access.
Terms
IP
IP stands for Internet Protocol. You will also see the term TCP/IP. TCP/IP is basically the glue that binds the Internet. It was developed by the Defense Advanced Research Projects Agency (DARPA), the folks that invented the Internet, as a way of ensuring communications among various and dissimilar computers and networks. IP is the signaling set that addresses the messages you send so that they will get to where you want them to go. In addition, IP identifies you to the network you are on, whether that is your LAN at home, your LAN/WAN at work, or across the Internet as a whole. To further understand how IP works, we use the following example. Think of how you send mail from your home to others.
You address the envelope, and put your return address on it. Every house in the country has been assigned an address.
Well, on a computer network each device connected must have an address in order to send and receive messages. Every PC, printer, scanner, etc. must have an address. Plus, these devices are not always located at the same place or even on the same network – I may have my laptop at home, work, or at a hotel. The Internet is like if each person lived in a camper – how could we assign everyone an address that would enable the post office to know how to get everyone their mail? Well, that’s what IP does. IP utilizes both “static” and “dynamic” addresses. Dynamic addresses means that each time you connect to the network, an IP address is assigned to you for that session only. When you’re not connected, that address can be used by someone else. Static IP addresses are assigned like your address at home – a fixed address that never changes. One more important thing to know – IP does not necessarily mean that you are using the Internet as the network to carry your signal. IP is just the signaling protocol. It may be that you are using your network at home, or your company’s network (LAN/WAN) and not the Internet at all.
