In-house DSL

Unanswered Question
Apr 20th, 2007

This probably isn't the best section for this post, but it is all theory based and I'm just looking for some expert opinions.

Lets say I own a big apartment complex. 100 rooms, all occupied. I want to provide internet access to my tenants but was too cheap to run CAT5 when proposed and am now in a bind. (no i dont own an apartment complex and im not that cheap)

So now im looking at the copper on all of the punch downs in my telco closet.

I say to myself, why not get a 10meg internet pipe, an access solution, and provide my own in-house DSL access to the tennants.

Is this possible? If it is possible, what other type of equipment would be needed to cross connect the punch downs to the AS?

Again this is all theory / lab based and your thoughts would be greatly appreciated.

I have this problem too.
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Paolo Bevilacqua Fri, 04/20/2007 - 12:47


sure it's possible. I think cisco does not make small/cheap dslams, but other vendors sure do.

beside 100 units not even *that* small a dslam.

You set the dslam, a recent model would use ethernet to connect the router and setup nat / bridging whatever as necessary.

At a telco products you would get the punch down, splitter, etc, that depends on the exact installation, genrally dslams have 50 pins telco connectors.

pstebner1 Fri, 04/20/2007 - 13:37

FWIW, you could also set up some wireless APs, but that will depend wholly on the topology.

Paolo Bevilacqua Fri, 04/20/2007 - 15:17

Agree, wireless would be the best solution. You run some backhaul links as needed, can do that nicely with the lightweight APs that are controllerd by the router or other appliance.

allenelson Fri, 04/20/2007 - 15:42

well i guess i should have given the run down on the complex itself.

every unit has access from an outside door, and the walls are 12" concrete block. even with AP's outside i'd still have to run cat5 inside of the units.

that's why i was asking about DSL technology.

but that's cool, so i guess the line card itself will patch right into a 25 pair cable? if that's the case then ya cross connecting would be a sinch.

i've never worked with a DSLAM and guess i'm asking dumb questions...

allenelson Fri, 04/20/2007 - 15:45

oh i forgot to add in the 2nd part.

the data runs on a different frequency, so i don't think this would be an issue, but, lets say Verizon provides the local access to the building for dial tone. these are all live circuits.

i won't be using the PSTN to establish the circuit, but will be using the copper. could this in anyway interfere with the tennants telephone service? (other than putting on a filter)

stephen.stack Sun, 04/22/2007 - 10:12

Hi allenelson, :)

I had the same dilema about a year ago. I was asssigned the task of designing an internet access solution for a student accomadation block. 57 apartments - 256 rooms - No Cat5, only 2 or 3 pair wires to each room.

Heres my case study. this may help you.

It this scenario wireless was the preferred option for students to access the internet. But the complex was to difficult to cable with CAT5 even for links to AP's, let alone a CAT5 to every room.

I looked closley at the telco distribution frame, and the type of voice that was running on the existing copper. some coppers were using standard analog signaling and some were using digital... (Different frequencies).

I looked a number of ADSL products but found them too expensive to use (ADSL DSLAMs are expensive). By luck i came across VDSL.

Very High Bit Rate DSL (aka LRE(Cisco)) was the technology of choice. It allowed (at the time) data rates of up to 16 Mbps which could be throttled. See here

Now that the technology was chosen it was time to choose the products. Cisco LRE (Long Range Ethernet aka VDSL) was very expensive for our budget as well as the fact that it was to be EOL soon. two other solutions were Zyxel VES 1124 and SMC7724M. We choose the Zyxel as it contained the WAN link and POTs Spillter in one.

Installing the Zyxel box was a breeze. It has all the same features as a standard managed switch - VLANs, STP, Port security etc... Cabling was also as easy as you might think. Both vendors provide good instruction on it.

All that was required was a VDSL modem at each end of the link to split voice from data. You can get analog modems and digital modems.

In our case, for the above amount of rooms, with high density concrete walls and floors, we used 24 port switch only, with 24 links used. at the end of each link was a modem splitting voice and data. The ethernet link on the modem was going in to a linksys WAP54G with two high gain antennae HGA7T on each WAP. This was enough to cover all apartments. (Be carefull to carry out a full site survey first tho, and as this is not your preferred option, i will not go on about it.)

All the above worked very well for us.

Two problems did arise.

1. there was some interference causing some of the modems to drop the connection to the switch frequently. We found (after some serious trial and error), that by reducing the bandwidth to the modem the problem was resolved. Technically, the higher the bandwidth the - higher the frequency on the copper. Higher frequency was more suceptable to noise.

2. File sharing apps taking up bandwidth. Cisco NBAR took care of this for us.

So, thats my case study, I woudl at this stage consider myself an expert on this type of work, as i have installed a few more since. I'm sorry if some points are not very clear, but bounce back to me and i will help all i can ( god knows if i had help when i did my first one - life would have been very easy for me :))

HTH ( Please rate if it does)



Paolo Bevilacqua Sun, 04/22/2007 - 13:11


Stephen's post is very valuable and derived from first-and experience.

They only thing different in my experience is the price of a small DSLAM, I saw the 48-ports from a leading European manufacturer and was not expensive, but perhaps it is because it was a special bid for an ISP. That product is also easy to configure via web or CLI. I would be more vary of DLAM of Asian origin.

Standard ADSL has the advantage that the modems can be bought everywhere and once installed is done (almost) forever. Wireless require more planning, maintenance and you may have issues with access control, and privacy.

Does it helps, if so please rate post!

stephen.stack Sun, 04/22/2007 - 14:30


Just to say that i agree with the fact that ADSL modems are standard and available at all types of configurations and costs.

The reason i have stuck with VDSL is that the complexs i worked in were not exactly 'ISP' type scenarios. So what i am saying is, i was allowed to tell the tenants what type of modem was to be chosen.

Saying that if it was a scenario where the tenant had to choose, i would select ADSL.

Nonetheless, both are easy to implement and maintain. (exepct wireless, of course ;) )



allenelson Mon, 04/23/2007 - 04:27

great post fellas. im glad i actually did ask the question. i highly agree in cases like this dsl is really the only way to go.. im not fluent enough in cable technology, or internet over power (anyone heard of it? maybe it's just buzzin around here in PA..) but those were also ideas popping around in my mind.

but anywho, i checked out a few DSLAM's from Versa technologies. 24 port DSLAM goes for $1100 and modems are 30 a piece. That seemed pretty reasonable to me. A full rack stacked with line cards totaling to 350+ ports went for $30,000. But they said the smaller 1 or 2u's have more support going for them. 30k isn't too bad for that but there isn't any fault tolerance.

Like you said about the speed, I'm not really worried about that because I think we're going to cap it at something like 1.5/256k for a quick ROI.

All in all, if it goes through I'll post my sucess/job termination at the end of the project. ;)

stephen.stack Mon, 04/23/2007 - 11:07


I did'nt know that ADSL was going so cheap. Great stuff. I would go with that if your bandwidth requirements are small..

Glad to help, and please tell all when job is complete.



allenelson Tue, 04/24/2007 - 08:06

Will do, and yes. Those are actually ADSL2 prices, which i dont need. I'm keeping low speeds and honestly don't need the support for 16mbps/2mbps or whatever it is..


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