To our knowledge Netopia was the only SDSL CPE vendor who had implemented support for the inverse multiplexing feature of CM DSLAMs, aside from CM themselves. And with regard to the last point, CM's own IMUX CPE appears to be almost non-existent vaporware, hence the SDSL community generally equates CM IMUX with Netopia.
Looking through the relic documentation we've been able to find on www.netopia.com, we see 3 IMUX product configurations mentioned specifically: R7171, D7171 and D3232. The existence of D3232 suggests that there also ought to be R3232, but we've found no mention of the latter in the ex-Netopia PDFs. A 7171 is an UMB3 with two CM SDSL wanlets and bonds 2 SDSL lines; a 3232 is an UMB3 with two dual ISDN wanlets and bonds 4 IDSL lines. We don't know if Netopia ever supported a 2-line IDSL IMUX configuration, either as a 3131 (two single ISDN wanlets) or as a 3200 (one dual ISDN wanlet).
IDSL doesn't arouse much interest any more as it's a little slow even with
a 4-line IMUX configuration (576 kbps), so the primary focus is on the
7171 configuration for SDSL IMUX, either R
or D
version.
It seems that the number of 7171 units that left the original factory assembly line as such is very small, and they are anything but readily available on the surplus market. Furthermore, thanks to Netopia's defective-by-design firmware, putting a 7171 together yourself by getting an R7100 or a D7100 from the surplus market and adding an extra SDSL daughtercard to it from another such unit is anything but easy.
First of all, getting the 2nd SDSL wanlet to work requires entering
the feature upgrade key
for IMUX, otherwise the unit will come up
with IMUX Support
listed as Not Installed
and disable the
2nd WAN card.
Getting the necessary key would be problematic: it depends on the MAC address
of the unit, hence one needs the magic generator tool, and that would be a
serious piece of unobtainium.
The Motorola folks who bought Netopia no longer sell these feature keys either.
But the problem doesn't stop there!
I happen to have an UMB3 (started life as an R7100-C) that does
seem to have the necessary magic feature key — I say so because it
lists IMUX Support
as Installed
when the 2nd WAN card is added.
But that 2nd WAN card is still disabled with the Ready LED lit solid red!
Trying to call Netopia/Motorola for support was absolutely fruitless:
they said something to the effect of having no one left in the company
who knows anything about these ancient products.
We have a working R7171 unit for reverse engineering purposes only thanks to MegaPath who have donated one from their little stash. We have used this unit to make some inroads toward reverse engineering of CM's IMUX protocol as described here.
However, it was also very interesting to examine this unit and observe its peculiar history. It appears that the R7171 units which do exist in the little stashes of ISPs like the one that was given to us did not come as such from the original factory assembly line. Instead it appears that such factory-original 7171 units are so rare that some enterpreneurs have made a little business taking surplus R7100s and D7100s, making 7171s from them and selling those units to the ISPs with a desperate need for such things.
Let's look at the unit we've got from MegaPath.
My first observation was of the LED legend strip: it showed signs of having
been peeled back and pressed back on, a tell-tale sign that someone has been
inside the box after it left the original factory assembly line.
(To be fair, it was pressed back on pretty well, an average end user would
have probably accepted it as perfectly new, but being a professional hacker
and reverse engineer I have a sharp eye for such things. :-)
Then the sticker on the bottom: there was a little sticker saying
Netopia R7171 SDSL Router
, but peeling it off revealed the original
factory sticker saying Netopia D7100-C SDSL CSU/DSU
.
Inside the box the motherboard also features a sticker saying D7100-C
along with the last 3 octets of the MAC address and a barcode —
no mistakes.
This R7171 was made from a D7100-C by some enterpreneur.
Whoever that enterpreneur was, he did a really good job.
The LED legend strip was pressed back on pretty well, the R7171 sticker on the
bottom looked proper, and the whole thing was packaged in an original Netopia
shipping box with all the extras!
The box probably came with the D7100-C from which the beastie was made, but
whoever repacked it included two of Netopia's original SDSL cables to make it
really look like it left Netopia as a 2-line router.
And to put the icing on the cake, the sticker with the barcode and the
firmware version number on the outside of the cardboard box says R7171!
I don't know how that one was done.
Why all the effort?
Well, I guess it had to look totally new, totally
professional and totally factory
for an ISP to buy it for the purpose
of issuing it to a subscriber...
The interesting question is of course how did that enterpreneur get the necessary feature upgrade key and whatever other black magic is necessary to enable the 2nd WAN card. Well, we may never know the answer for this particular case of MegaPath's R7171 stash, but one member of our project mailing list has told me that he used to know someone inside ex-Netopia who provided him with the keys, and he had in fact put together and sold 7171 units in just this manner. Perhaps MegaPath's stash came from him, perhaps from someone else doing the same thing.
While Netopia's IMUX offerings were originally CM-specific, they were later expanded to support MLPPP as well on models such as R7272 (bonding two SDSL/ATM lines with MLPPP) and R6161 (bonding two ADSL lines with MLPPP).
We don't know if getting a 2nd SDSL/ATM or ADSL wanlet to work and to avail itself for MLPPP bonding also requires jumping through insurmountable hoops with feature keys and the like, but we won't be surprised if it does.
I don't want to shed any tears over my lack of success in putting a 7171 together myself from pieces, and I very strongly encourage everyone else not to waste their energy on such pursuits — Scatopia's crap does not deserve to have your energy wasted on it! Instead let us focus our efforts on building an entirely new open source modular router hardware platform of our own: see this page.