how-to block ads
provided the content for
this FAQ in this Thread
ATM is used from the modem to the DSLAM, but the authentication and control, which is PPPoE, is encapsulated within the ATM cells.
C. O. based DSLAM's are DS3 sized pipes that traverse across the ATM cloud, and eventually will aggregate with other DS3 connections to an OC3 port that feeds a particular RedBack at ASI.
The Remote Terminal, being field based, are Telco owned and operated. The circuits will eventually terminate on an ASI RedBack, but must first traverse the Telco network. This includes circuits originally terminating on an OCD device, which concentrates the circuits of several individual Remote Terminals , then terminates them as 1 logical pipe to the OC3 port of the ASI RedBack.
If the ASI RedBack has say 10 PVC's terminating on it's OC3 ingress port, 7 may be individual DSLAM PVC's, and the 3 remaining may be Telco Remote Terminal PVC's, which in turn may contain several Remote Terminal circuits within each connection.
Where ASI sends the traffic to SBCIS, or any other ISP, from that point depends on customer density aggregated PVC count on the ISP end, proper traffic balancing, or any number of other factors. Once in the ATM cloud, for example the distance between the Chicago POP or the Elmhurst POP, and any RedBack router within the respective POP's, is irrelevant.
Remember the RedBack you see in a trace route to your IP address is the ISP RedBack, not the ASI RedBack. This is because it is the first point at which you are at Layer3. Look to your Enternet300 properties (or whatever PPPoE client you are using), and you will see another RedBack name/Access Concentrator/AC - that is actually the ASI RedBack...the PPPoE server.
How about a picture
A brief description for some of the acronyms is here:
List of common acronyms from the Bellsouth FAQ.