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ADSL modems to connect LANs

By mi_tasol ·
Does anyone have experience using ADSL modems to connect two separate LANs? Currently we connect 24/7 using a 56K modem at each end and a dedicated phone line. Can I place an ADSL modem at each end to connect the two using the same copper pair? I think the answer is yes, but need more details.

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by rainbow In reply to ADSL modems to connect LA ...

Swop your ADSL modem for a ADSL router & connect it to your switch/hub. Change default gateway to router address.

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by TheChas In reply to ADSL modems to connect LA ...

Are these networks in the same building?

If not, how far apart are they?

If the buildings are too far apart to physically connect the 2 networks, you will not be able to have a simple connection over ADSL.

At a minimum, you will need to setup a VPN or similar network protocol.

Unlike your dial up connection, you cannot call one DSL line from the other DSL line.
You have to connect through your ISP.

Even then, does your ADSL connection include a fixed IP address?

Also, does your ADSL contract allow for the volume of uplink data you need?

While ADSL will be faster for downloads, you will be limited by the upload speed when transferring data between networks.

For connecting 2 sites, you need to look at SDSL. That way your uplink and download rates will match.


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by TheChas In reply to

I just read your question again.

While for dial-up, you only need the phone company for the dial tone and to maintain the connection, DSL requires a bit more help from the phone company.

DSL transports your data on a high frequency signal sent as a separate carrier over existing phone lines.
Without the carrier from the central switch, the DSL modem does not enable.

To connect your 2 networks with DSL modems, you would need to generate the carrier wave.

I think that you would need a device that acted as a data coupler generating a separate carrier for each end of the line, while allowing data packets to be transfered between both modems.

I assume that you lease your dedicated line.

If so, I suspect that if you did a full trace on the line you would find that it makes it's way back to some form of phone switching station.


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by mshavrov In reply to ADSL modems to connect LA ...

I've never heard about anyone who has two ADSL modems connected to each other without help of ISP. In theory it's quite possible, but again, I have never heard about this.

Second, if you will get ADSL services in both locations, be aware, that it's Internet connection with all security problems. So, you will need routers/firewalls in both locations. Plus, you will need to establish VPN connection between your networks. You can but VPN Routers (I think LinkSys has a few models), which will do both, protect your network from the Internet, and build VPN tunnel to interconnect networks. But if you have good budget, I recommend to get Cisco PIX firewalls instead.

If you have more questions on design, just e-mail me.

Good luck,

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by wlbowers In reply to ADSL modems to connect LA ...

Two routers, like Cisco 1750's with T1 cards will do what you want.

Call Cisco and they will configure the hardware and software.


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