DOCSIS, Which is Faster: DSL or Satellite Internet, Difference Btw ISDN and DSL

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What is DOCSIS

Data Over Cable Service Interface Specification (DOCSIS) defines the interface standards for cable modems and supporting equipment involved in high speed data transfer and distribution over cable television system networks. It permits additional high-speed data transfer over an existing cable TV system and is widely used by television operators to offer Internet access through an already existing hybrid fiber coaxial infrastructure. Other devices that recognize and support DOCSIS include HDTV's and Web-enabled set-top boxes for televisions. In other words, the same cable that brings you CSI can also allow you to send email and receive Internet news.

CableLabs developed DOCSIS and this technology has been approved as a standard for cable modems by ITU.

DOCSIS Architecture

The DOCSIS architecture consists of two primary components. 1) A cable modem located with the customer and, 2) the cable modem termination system operated by cable service providers. The second function is to perform as a Hi Speed way station for multiple cable modems and then communicate with the system network. DOCSIS defines protocol for bi-directional signal exchange between these two components through the use of cable.

DOCSIS Types

DOCSIS 1.0 debuted in March 1997 and is what most consumers typically link with high speed cable Internet access . This version facilitates a downstream traffic transfer rates of 27-36 Mbps over a radio frequency (RF) path in the 50 MHz to 750+ MHz range, and upstream traffic transfer rates between 320 Kbps-10 Mbps (average 5 Mbps) over a RF path between 5 and 42 MHz. In layman's terms when more people who use DOCSIS 1.0 are using the Internet the slower the overall speed will be for customers.

DOCSIS 1.1 can coexist with DOCSIS 1.0, but features an increased upstream data transmission and improved security. This version facilitates multiple services such as voice and streaming. The end result is faster transmission and reception with a greater inventory of features.

DOCSIS 2.0 has an added capacity for symmetric services by operating at 64 QAM, backed by a new 6.4 MHz wide channel. Enhanced modulation and improved error correction ensures that this standard offers an increased bandwidth for IP traffic. The upstream traffic DOCSIS 2.0 is above 30 Mbps which is 3 times better than DOCSIS 1.1 and 6 times faster than DOCSIS 1.0. DOCSIS 2.0 is interoperable and backward compatible with DOCSIS 1.x. Long story short - this version works with both of the others but remains much faster and exhibits fewer errors.

The latest development in cable Internet connection is Embedded DOCSIS (eDOCSIS). eDOCSIS is designed to provide subordinate services at the core chip level to the host device. Its purpose includes end device management (including traffic management), configuration and security issues to significantly reduce cost in the service operation and to enhance speed and quality of end customer services. This evolution of service provides greater overall speed, reduced costs, and is less problematic for your service provider.

Global DOCSIS Standards

Because frequency allocation plans differ between European and US counterparts, a separate European DOCSIS has been developed exclusively for European countries under the name 'EuroDOCSIS'. The main difference between the two standards is in the TV channel bandwidths. For example, European TV channels confirm to PAL TV standards while American ones confirm to NTSC standards. In comparison, the wider bandwidth of EuroDOCSIS is advantageous to Internet users because it has more bandwidth that can be allocated towards downstream data path.

Japan has developed its own version of DOCSIS that is further distinguished from either of the existing services in either Europe or the US.

Transfer Rates

Most DOCSIS cable modem service providers implement caps on upload and download rates to suit their different configurations. For example, Comcast, the largest cable TV network in the U.S. caps the download bandwidth at 6 Mbps and upstream bandwidth at 384 Kbps. The caps are set by sending a configuration file to the modem via TFTP, at the instance when the modem establishes a connection to the provider server for the first time. The caps vary with different players. Most companies offer higher download rates, but you can expect to pay more for this service.

Is DSL Faster than Satellite Internet

DSL, also called digital subscriber line, is a technology that delivers broadband Internet to many people's homes via their conventional telephone landline. DSL is one of two popular broadband Internet technologies used for the home market, the other being cable broadband which uses existing cable TV lines to deliver broadband Internet.

Another growing technology for delivering broadband internet to homes is Satellite Internet technology. While nowhere near as popular yet, satellite internet technology is gaining popularity in rural areas where landlines or cable TV lines are not available. In addition, satellite Internet technology is also a possibility for those homes that have satellite TV. The only thing usually required is a clear view of the satellite.

Which is Faster: DSL or Satellite Internet

For those looking for an answer to this question, you will be happy to know that there is a clear-cut answer. DSL is in almost every case the faster broadband Internet technology available.

DSL broadband Internet technology can usually deliver speeds to a home from between 2Mbps to 8Mbps. On the other hand, satellite Internet usually delivers anywhere from 512 Kbps to 2Mbps. DSL broadband internet is also much cheaper than satellite internet. For instance, you should expect to pay about 3 times as much for comparable bandwidth and the modem and other equipment can cost you hundreds, if not thousands of dollars.***( Not so. My Verizon DSL is 54mbps. Even when busy, it yields 36 mbps.)

While satellite Internet does offer those in rural areas a great way to connect to the Internet at a decent enough speed, there really isn't any challenge when comparing whether satellite is faster than DSL.

What is the Difference Between ISDN and DSL

Definitions

Integrated Services Digital Network (ISDN): ISDN is a digital transmission system, which is used to transmit voice and data through copper telephone wires. In other words, it's a circuit-switched data transmission system that is used for voice and data transmission over the wire.

Digital Subscriber Line (DSL): DSL is also a digital transmission system and utilizes already installed copper wires to send voice and data packets.

Differences

As far as the differences between ISDN and DSL transmission system are concerned, there are several differences one can find:

Speed

In terms of speed, DSL is faster than ISDN. DSL sends data packets with speeds ranging from 128Kbps – 1.5Mbps. On the other hand, ISDN comes in two different speeds i.e., 64Kbps and 128Kbps.

Price

In terms of price, ISDN is somewhat more expensive than DSL. The main reason is that DSL utilizes wires that are already installed into homes or businesses, and there is no special line installation needed. However, ISDN lines need to be installed and connection charges vary depending upon the connection you choose. In case of dedicated or, "always on" connections – you will have to pay more as some ISDN packages are charged on per minute basis. A special dial-up package, on the other hand, will cost less and might be an easy option where a DSL connection is still not available.

Technology

ISDN is a dial-up service and transmits voice and data through a single line. There are two types of ISDN: Basic Rate Interface (BRI) and Primary Rate Interface (PRI). BRI is used mostly for residential homes and comes with three channels. On the other hand, Primary Rate Interface (PRI) ISDN is a business version and comes with 24 channels. In this case, 23 B channels are used to transmit voice, data and video – all through the same wire. A D channel carries low speed data and signaling. This signaling is used to generate alarm signals and provide support for non-voice functions. ISDN does not transmit data through analog lines.

DSL connections are often referred to as "always on" connections, so don't do not need to dial up a number. In DSL, there is only a single route for carrying voice, data and video. Two types of DSL connections are widely: Symmetric DSL (SDSL) and Asymmetric DSL (ADSL). These two types of DSL connections differ in their data carrying capacities i.e., upload and download. For more downloading, ADSL is a better choice.

ISDN and DSL are both distance sensitive. To get either service, your place should not be more than 18,000 feet away from the central office.