Copper Mountain was a very fine DSL company, which sadly exists no more. CM DSLAMs are built as solid as tanks, and they were used by the venerable old Rhythms DSL network, which later became WorldCom's Enterprise DSL network and which now also sadly exists no more thanks to the bean counters at Verizon.

In technical terms CM had done several good things:

They did not use ATM on their SDSL and IDSL circuits.
They provided a high degree of support for using their SDSL more like a traditional leased line, at least if the DSLAM was used in the cross-connect netmodel (see below).
They allowed their proprietary CMCP (see below) to be disabled per-line.
They did not require the use of their proprietary CM 1483 encapsulation (see below) and allowed the operator to switch an individual subscriber to a standards-based encapsulation.
They gave their stamp of approval to Larscom CupreDSU, a totally bit-transparent SDSL to V.35 DSU.
Their CR202 IMUX CPE offered a V.35 hand-off too.

However, they have also made two major blunders which are very much in need of criticism:

When the DSLAM is used as an IP router, it stupidly refuses to serve out true routed DSL circuits, only MAC-encapsulated or bridged ones.
Their SDSL bonding feature (see below) uses a horrendous proprietary scheme instead of standard FRF.16.

Getting a CM SDSL line

With Rhythms and CM itself being gone, we thought that there are no more major DSL providers left who provide SDSL served from CM DSLAMs, and that all remaining operational CM DSLAMs belong to small town providers who run a DSLAM or two by themselves independent of any major network. However, we have since learned about DSL.net (now part of MegaPath), another largish network (although not as large as Rhythms) also based on CM DSLAMs. They appear to serve SDSL from CM DSLAMs to the present day, but unfortunately they have a rather limited geographic footprint (see our write-up of MegaPath/DSL.net).

Let's just hope, wish and send our positive intent that those fine folks who still operate CM DSLAMs stay in business! (No need to worry about the DSLAMs themselves — they are built so solid that they'll probably outlive their operators.)

Connectivity to CM SDSL & IDSL

If you succeed in getting a CM SDSL or IDSL line, how do you connect to it? The answer depends on the type of circuit, or more specifically the following two critical questions:

Is it bridged or routed? (See this page for explanation.)
Is it a single line or an IMUX bundle?

If it's a single line (not an IMUX bundle), the CPE choice is straightforward:

If you have a bridged or MAC-encapsulated circuit, use CM's own CopperRocket. That little box will turn the CM 1483 MAC encapsulation into an actual Ethernet interface, but do absolutely nothing else to it — you can then take it from there.
If you have a true routed circuit and would like to connect it to a router of your choice instead of the soapbox crap, use the XSB-2000 SDSL-to-V.35 DSU. It's a totally bit-transparent DSU, not a pseudo-DSU like Netopia D7100!

IMUX bundles are a different story altogether — see the IMUX page.

Our own CM DSLAM

We, the group running this project, are proud to own a CopperEdge 200 DSLAM ourselves! (It is from eBay; examination of the configuration stored inside has releaved that the unit used to belong to NorthPoint, an ill-fated DSLAM operator that appears to have been very similar to Rhythms judging from the configuration table that was on our DSLAM.) The unit is fully loaded with 6 SDSL line cards and 2 IDSL ones, each serving 24 ports. That's a lot of SDSL lines!

We have this DSLAM set up in our lab and we've used it to clarify some of the information on these pages.

Our CM knowledge base

Getting a CM SDSL line

Connectivity to CM SDSL & IDSL

Our own CM DSLAM

FTP