Cable Modems: A cable modem is a box that uses the coax cable your cable company uses for TV signals, to transmit data. Since cable TV was designed as a broadcast system, the cable is shared amongst many people in a small area, and speeds depend on the network usage amount. If you have packet loss on a cable connection and have tweaked your system, know that the problem might be from an overcrowded network. Internet usage on a cable modem during peek times is frustrating sometimes, especially for gamers, so if you have no other choice than cable, then go for it.

DSL (Digital Subscriber Line): DSL is the next generation of internet access technology. A house or business with DSL has a data socket that looks like a phone socket. DSL is a direct connection to the Internet, always on. There are few types of DSL services:

• ATM: Asynchronous Transfer Mode is a high speed network protocol, especially good for real time voice and video. DSL lines normally use ATM as the underlying data-transport protocol beneath TCP/IP.
• Local loop: The local loop is the line between your house, and the local central office where telephone travels on twisted pair of wires.
• ADSL: Most popular type of DSL where speeds as asymmetric. Download speed is usually much faster than upload speed. You will need to be close to a central office (where all the phone lines connect in a neighborhood) in order to get 1.5mbps download/128kbps upload speeds, which is the typical speed for residential products.
• SDSL: Very good alternative to a T-1 for business users where download speed and upload speed are the same. SDSL uses two pairs of wires where data and voice is split inside the phone jack compared to a filter on ADSL. You will need to give up a phone line completely if you plan on installing SDSL. SDSL is usually more stable than ADSL since speeds are symmetric and the connection is better maintained for business purposes such as running servers. Also, SDSL is excellent for gaming on the Internet.
• HDSL: High bit-rate Digital Subscriber Line is a DSL modem that delivers T1 speeds (1.5mbps/1.5mbps). This requires two lines. HDSL isn’t for residential, but for commercial zones.
• VDSL: VDSL offers the highest speeds of the DSL types, but is only in limited commercial use. Companies require you to be 1000 to 4500 feet away from the central office but it promises data rates of up to 50mbps. VDSL has been previously called VASDL or BDSL or even ADSL. In June 1995, VDSL became the official title of this standard. As of early 2000, VDSL has appeared in some US-West areas; for example, Gilbert and central Phoenix. Those subscribers report great service, highly integrated -- TV, phone, Internet all down one short line from a local fiber connection.
• IDSL: IDSL is DSL at 144 kbps down and up. IDSL uses ISDN transmission coding both ISDN channels and voice all on one circuit. IDSL does not use any kind of dial up nor involve call fees. IDSL is usually the only option for those who are too far from the CO to receive regular ADSL or SDSL, but recently there has been a project launched named “project pronto” which installs mini-CO’s in neighborhood and increases the chance of getting ADSL or SDSL by a big margin. That’s actually how I received ADSL; through project pronto. IDSL is a little more expensive than any regular DSL service but IDSL can still be a very satisfactory solution to dialup, coping very well with online gaming, and medium quality streaming audio/video.

UDP: UDP packets are used where delivery is not guaranteed. Of course delivery of most packets is highly likely, its just that some of it may not get there. What use is that? Well, for some information like video and audio, some loss of data can be tolerated. The advantage of UDP is that the sender and recipient agree on a constant data rate. This means that you don’t have to run the link as fast as you can, which is the natural design of TCP/IP. UDP is used by multiplayer games like Quake 3, and Half-Life,...

WinModem (/HSP Modem): If a modem is advertised as Windows-only, it is probably software-based. Modems consist of two major components:

• A datapump performs the basic modulation/demodulation tasks for which modems are named
• A controller provides the modem's identity: this is where the protocols for hardware error correction, hardware data compression, and basic modulation protocols (such as V.34, x2 or K56flex) exist. The controller is also responsible for interpreting AT commands.

A traditional modem implements both features in hardware, as chips inside the modem.
A controllerless modem, such as the U.S. Robotics (now 3Com) Winmodem, still has a hardware datapump, but implements the controller function as software.
An HSP modem dispenses with both the controller and the datapump, and uses software to provide both functions. Short for host signal processor, HSP modems transfer the work normally done by the missing chips to software running on the host computer's main processor (the 486, Pentium, PowerPC, etc.)

PPPoA: ADSL access via Point-to-Point Protocol (aka Dial-Up Networking). The "FastAccess ADSL" icon is located in the Dial-Up Networking folder. The user authenticates with userid and password, then connects. This is similar to dialup except no actual dialing takes place. Only available with the PCI or USB modems (or various unsupported alternative modems and routers).

PPPoE: Another dial-up type connection method. PPPoE and PPPoA are different VC Encapsulations. They differ in some ways (the most important is that PPPoA allows for MTUs of 1500), but there is mostly no difference in speed between the two.

Latency versus Bandwidth: One of the most commonly misunderstood concepts in networking is speed and capacity. Most people believe that capacity and speed are the same thing. For example, it's common to hear "How fast is your connection?" Invariably, the answer will be "56K", "640K", "1.5M" or something similar. These answers are actually referring to the bandwidth or capacity of the service, not speed. Speed (latency) and capacity (bandwidth) are two very separate things. The combination of latency and bandwidth gives users the perception of how quickly a webpage loads or a file is transferred. It doesn't help that broadband providers keep saying "get high speed access" when they probably should be saying "get high capacity access". Notice the term "Broadband" - it refers to how wide the pipe is, not how fast.

QoS: QoS stands for "Quality of Service" and it is the idea that transmission rates, error rates, and other characteristics can be measured, improved, and, to some extent, guaranteed in advance. QoS is of particular concern for the continuous transmission of high-bandwidth video and multimedia information. QoS RSVP Service provides network signaling and local traffic control setup functionality for QoS-aware programs and control applets. Supposedly It provides a form of load balancing that shifts bandwidth between applications where it's most needed.

VPN (Virtual Private Network): A virtual private network (VPN) is a way to use a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization's network. A virtual private network can be contrasted with an expensive system of owned or leased lines that can only be used by one organization. The goal of a VPN is to provide the organization with the same capabilities, but at a much lower cost. A VPN works by using the shared public infrastructure while maintaining privacy through security procedures and tunneling protocols such as the Layer Two Tunneling Protocol (L2TP). In effect, the protocols, by encrypting data at the sending end and decrypting it at the receiving end, send the data through a "tunnel" that cannot be "entered" by data that is not properly encrypted. An additional level of security involves encrypting not only the data, but also the originating and receiving network addresses.

Note : You may visit http://www.dslreports.com/faq/ for more terms.