How can I test VDSL modems without having a VDSL line with openwrt?

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1

I was researching about this, it seems I might need a PPPOE server thing? I think this is doable with openwrt.
Here is the thing, I test VDSL modems and refurbish them if they need to be. But, I don't have VDSL line, it's all fibre here. Can I use an openwrt router that simulates, that as if it sends VDSL signals to the modems I want to? I mean all those network devices are just "computers" after all. It should be possible? I think this require a PPPOE server am I right?

I came accross this, is this what I would need? https://openwrt.org/user/ahorner/pppoe_server_guide
If I do this, how to send that data to a VDSL modem's DSL port? How would it work though?

2

Ordinary modems (CPEs) can't do what you are trying to do. You won't get connection at the ATM/PTM layer. You need a DSLAM if you want to test DSL modems.

If you only want to test PPPoE client functionality, you can set up a PPPoE server and connect to the modem via Ethernet WAN port (not DSL) and set the WAN to PPPoE.

3

Isnt there an ethernet to dsl cable, or some converter thing? That DSLAM thing is extremely expensive.

4

There are VDSL master modems like
https://www.allnet.de/de/allnet-brand/produkte/alle-produkte/p/allnet-all126am3-vdsl2-master-modem-fuer-2-draht-verbindungen/
or
http://shop.allnet.de/detail/index/sArticle/246734
(excuse the language), but it is not clear whether these require special modems on the other side, or whether they will work with the modems you want to use...
On the other hand ISP all over Europe should be retiring their DSLAMs, so maybe you can get a second hand DSLAM somewhat more affordable.

5

Maybe see this:

Planet VC-231G might be what you are looking for...

2 Likes
6

That might be it. But, 150$ hecking dollars? Omfg that is soo expensive for a damn VDSL bridge. FAK.

7

Maybe used ones will be cheaper. My pair of converters costs $40 at a local classifieds website.

8

Best I can see is 120$. Is this even easy to use? How does it work?

9

They work ok, and on a short phone line they reach 180/100 Mbps. The only thing that worried me was packet loss, but I reduced it by increasing the SNR Margin. I think they are not worth $120. Over a short distance (50m) even Fast Ethernet works over two pairs of telephone cable :wink:

10

I don't use them on a daily basis in production.
I use them to emulate a DLAM, and they prove that a VDSL modem on a lantiq can achieve throughputs > 160 Mbps with pure IP traffic. The problem occurs when we have simultaneous VLANs and PPPoE.

11

Cant I just do something without this even? Like connecting some of the pairs of cat6 to dsl cable? Without even using this thing?

12

You can not test whether the VDSL parts of a VDSL modem work without establishing a VDSL link. But you certainly can test PPPoE without a VDSL link, so it really depends on what you want to achieve...

13

I wanna achieve something very very cheap of course :smiley: This 100$ thing is far out.

14

Unless you're very lucky to stumble over a used deal, this kind of device is not going to be cheap. They are relatively rare and special purpose, produced in homeopathic quantities for (semi-) professional use (and maybe fttb), which has an effect on prices. And their master-slave firmware is usually only tuned to support its official counterpart on the other, so interoperability with 'normal' xDSL modems is hit or miss.

The real chassis and line cards used for fttc in larger numbers don't hit the secondary markets that often - and if you can manage to resurrect them on your lab bench is another question (no access to software, considerable power- and cooling requirements, etc. pp.).