Cable Broadband:



Motorola Surfboard Cable Modem
Motorola Surfboard Cable Modem

Cable Broadband is an internet connection technology which piggybacks on existing cable infrastructure used for television. It is generally used to bridge the "last-mile" in a network. Since cable broadband generally uses the existing cable television infrastructure, the network topography is similar to the current cable scheme of backbone-to-node, and node-to-client. Most providers currently use the DOCSIS 2.0 standard for the transmission of data over copper, and many are in transition to the newer DOCSIS 3.0 standard. Cable broadband, along with digital subscriber lines, provide the majority of broadband access within the US.


Network/Infrastructure:



Early cable broadband providers made use of the copper trunks and distribution networks already in place. Equipment providers for these early deployments(see LANCity) provided solutions that were designed to integrate into existing cable plants with few modifications. During this time, the average bandwidth provided to consumers, as well as the utilization percentages, were low enough that few capacity issues existed. Many rural providers that lacked the equipment needed for two-way communication implemented a one-way network infrastructure wher
HFC Network Diagram
HFC Network Diagram
e end-users utilized a dialup modem for upstream data transmission.

The introduction of the unified DOCSIS 1.0 standard in the late 90’s and the increasing demand for faster consumer data services led to a shift in distribution infrastructure. The copper backbones that had served communities with video services for decades could no longer support the large amount of IP traffic being generated. In response, cable providers began converting any remaining copper-backbone networks into a Hybrid fiber-coaxial (HFC) infrastructure. HFC infrastructure uses strategically placed nodes fed by a fiber optic backbone to serve customers. This design is better suited to and provides more capacity for IP based data transmission, while still utilizing the existing copper wiring in customers' homes. Internet service providers are currently upgrading equipment to the DOCSIS 3.0 standard (which dramatically increases data transfer rates and adds support for IPv6) and will also be accompanied by the deployment of more nodes (and a corresponding decrease in the customer-to-node ratio). Fewer customers per node decreases the probability of a node becoming saturated, as well as allowing a higher downstream and upstream bandwidth cap per user.


DOCSIS Version Speed Comparison:

Version
Downstream
Upstream
1.x
38 Mbit/s
9 Mbit/s
2.0
38 Mbit/s
27 Mbit/s
3.0 4channel
152 Mbit/s
108 Mbit/s
3.0 8channel
304 Mbit/s
108 Mbit/s


Consumer level Competition/Alternatives:



While coaxial cable based broadband is seemingly the most popular source of consumer level broadband, there are alternatives. One may choose any of these alternatives for many different reasons, such as availability, speed, and reliability.

FiOS: Fiber-Optic Service, offered by Verizon, is an offshoot of traditional cable and telco offerings in the sense that the provider offers TV, Internet, and Telephone service. The only difference is that FiOS’s network is comprised of an entirely fiber-optic network instead of the hybrid network that cable companies typically deploy. Traditional cable companies only use the faster fiber-optic cables to connect cable plant-to-plant and plant-to-node, and not node-to-home. Verizon’s entirely fiber optic network makes for faster Internet speeds, with the only downside being the availability of the service. Only a select few cities in the United States have FiOS service. Coaxial cable has been in use for decades for television signal distribution, so it is widely available to much of the public. To get fiber optic service, Verizon has to deploy an entire network from the ground up, utilizing the existing power poles and underground distribution infrastructure. Once rolled out, to get the service, a tech simply connects the fiber-optic service to your home's existing RG-6 cabling.

Satellite Broadband: Satellite Broadband uses geosynchronous satellite communication to deliver internet content. Its main advantages are availability and portability. It can be used anywhere in the world, miles away from the nearest civilization. Due to this, the service is immensely popular on boats, secluded houses, and RV’s. The primary drawback is its high latency, in some cases it takes over a second to get a response from a server. This makes it a very bad choice for Internet activities that require a low latency such as online games and video conferencing. It’s also been known to cost two to three times as much as Cable or DSL.

DSL: Digital Subscriber Line/Loop is an Internet service offered by traditional phone companies or Competitive Local Exchanges. DSL modems plug into traditional phone lines and offer speed comparable but often slower than cable. Since traditional phone wiring has been implemented in houses for more than a century, DSL can be offered to much older residencies without drilling any holes or running additional cabling. Also, because the phone network usually reaches out further than cable networks, it is very likely that even secluded homes can access DSL through the deployment of a remote DSLAM. Unfortunately for some users, because of a phenomena known as attenuation, the further a user is from the phone company’s hub or DSLAM, the more a signal degrades, limiting connection speeds.


A table showing the Pros and Cons of different methods of gaining broadband.
A table showing the Pros and Cons of different methods of gaining broadband.




Related Links:




References


  1. http://en.wikipedia.org/wiki/Cable_internet
  2. http://www.dslreports.com/faq/faq
  3. http://en.wikipedia.org/wiki/Cable_modem
  4. http://en.wikipedia.org/wiki/Docsis
  5. http://docsis.org/
  6. http://en.wikipedia.org/wiki/Verizon_FiOS
  7. http://en.wikipedia.org/wiki/Satellite_Internet_access
  8. http://en.wikipedia.org/wiki/Digital_Subscriber_Line