Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

DSL ISP - General systems layout / ideas.

Hi all,

I am really interested in getting more involved in this ISP level stuff.

I started working for a small ISP 2 weeks ago they serve around 6000 users here in Australia and I am trying to get my head around exactly how a facilities based ISP works.

So anyway, here is what I know roughly so far and please correct me if I am wrong and please be as technical as possible!

Basically, a high-speed line (local-loop) connects the actual ISP's facilities to the (usually) national backbone, this pipe is made up of 2 lines one up stream and one down.

This is then piped.... through what?

and then is delivered through a line connecting the users to the ISP... (is this the same pipe as the local-loop?)

As you can see I know well frankly nothing, but I am young and want to learn ALOT! Mainly on DSL level stuff if possible.

Is there any possibility some people can help me out here explaining the concepts of how it all works. Diagrams would be nice too.

Thanks to anyone that can help feed my brain.


Re: DSL ISP - General systems layout / ideas.

If the DHCP server is going to be located at the NSP, the NAP aggregation device must have a route to reach that server. The only scenario in which a NAP would use its own DHCP server and IP address range is when it wants to offer service selection capabilities to the subscribers, and those subscribers are LAN attached to the NAP.