Broadband Delivery Options:
A Cisco Router Tutorial
By Chris Bryant, CCIE #12933
When it comes to connecting remote users to a central office, there's nothing like broadband! Broadband offers several advantages over conventional dialup connections:
Increased speed
Broadband is always "on" , where dialup requires a connection to be established each time remote connectivity is needed
Broadband doesn't tie up a user's phone line, where dialup does
Upstream, Downstream
These seemingly innocent terms can actually be a little confusing - after all, the meaning of the terms can depend on which angle you're looking at things! For terms of our discussion and your Cisco exams, upstream traffic is traffic going from a host device to the cable company and/or ISP, and downstream traffic is traffic going from the ISP to the host device.
Broadband Delivery Options
The most common broadband delivery method in use today is the good old cable modem. The end user's connection is carried through a preexisting cable TV connection, enabling many cable companies to offer "do-it-yourself" broadband connectivity kits. Ever notice how the lights on the front of a typical cable modem flash quite a bit on startup, but some of them become solid green (we hope) ? That's because when a cable modem is powered on or reloaded, it begins to look for a signal from the service provider as it boots up. When that signal is found, the cable modem synchronizes its timing with the downstream provider device, and the connection procedure continues from there.
The potential drawback is that the end user is sharing bandwidth with a lot of other users, which can be a problem if the provider doesn't have enough bandwidth to go around.
The end user can simultaneously access the Internet while watching cable television due to the Data Over Cable Service Interface Specification (DOCSIS) standards. These standards reserve a portion of the cable's bandwidth for data transfer.
Now we need to take a look at the cable modem startup procedure - just click on that link to do so!
To your success,
Chris Bryant
CCIE #12933
chris@thebryantadvantage.com
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