Connecting 2 locations over wifi & share/bond internet connections?

[Sum Guy]

Say I have two locations (separated by about 1/2 mile) and I use something like a pair of Ubiquiti Airgrid M2 to give a wireless link between the two locations.

Each location is served by separate 6-mbps DSL connections (different ISP's, if that matters). So at each location there is a DSL modem connected to a router from which all PC's and devices get internet access.

With a wireless link between the two locations, what other equipment or devices would I need such that the full internet bandwidth of both sites could be shared/bonded or otherwise be made available to all PC's and devices at BOTH locations?

I presume that a dual-wan router would need to be used - at both locations? How would this look in a network-topology / connectivity diagram?

 

[stevech]

May not be worth the hassle.
Perhaps a scheme where you setup 2 VPN / tunnels, one in each direction, then take the terminated VPN and treat it as a 2nd WAN connection.
This is sounding expensive, for just 6Mbps connections.

 

[PrivateJoker]

May not be worth the hassle.
Perhaps a scheme where you setup 2 VPN / tunnels, one in each direction, then take the terminated VPN and treat it as a 2nd WAN connection.
This is sounding expensive, for just 6Mbps connections.

I agree that sounds like a pretty complex setup with who knows what kind of results to expect.

It'd probably be easier to get 12 Mb/s connection at one location and do a high powered bridge, but still it'd probably be a less than optimal design unless it's like at research complex on Antarctica where there are no alternatives.

The whole reason I got into DD-WRT a few years ago was trying to do run high powered, directional antennas to link 802.11g over longish distances, and yes you can do a science experiment and prove it works kind of easily, but if you wanted to make use of it the time and equipment necessary to get a usable connection is steep.

 

[stevech]

High powered bridges... that come from antenna gain such as the built-in antennas in bridges such as from Engenius.

DD-WRT's transmitting power settings are grossly misleading. The graphical user interface calls for/requests more power than the device can produce so the low level firmware ignores the user interface request. The transmitter RMS power varies - lower at the higher modulation rates, e.g., 30mW max RMS is what most chipsets do, at the highest modulation rate. Most do 60mW or 100mW at the very lowest rate. This is caused by the need in OFDM to accommodate the high peak-to-average ratio as the modulation rate increases. A 5-6dB "backoff" in transmitter power is common. This backoff has to be done else the transmitted signal would be too distorted (poor "rho"), causing higher retransmission counts which lead to lower throughput at the IP layer. Esp. bad when there are lots of uncorrectable errors due to lack of back-off, OR too-cheap 3rd party "amps" which cause distortion.

You won't see that all this is happening in the user interfaces, including DD-WRT. You can see retransmission ratess with a good WiFi sniffer. For each WiFi frame with an uncorrectable error, per 802.11, the receiver simple does not ACK. A long time later, the sender times out receipt of the ACK and retransmits and hope this frame succeeds. The distorted transmitted signal has the same effect as a weak signal (poor SNR).

The WiFi alliance is supposed to check the "rho" (distortion) of each product before it is WiFi certified. I don't think the do so any more. We rely on products using the "reference" designs from Broadcom and others. This is not an FCC issue- the FCC doesn't care if you transmit a distorted signal - just stay in your band and stay within the RF power limits. Lord knows what really goes on in the penny-pinching garage shops in Asia re avoiding distortion in transmitted signals with their own PAs.

 

[Sum Guy]

I agree that sounds like a pretty complex setup with who knows what kind of results to expect. It'd probably be easier to get 12 Mb/s connection at one location and do a high powered bridge, ...

The highest DSL available at either location is 6mbps up, 800kbps down (sync rate, not effective rate).

This is not a "mission-critical" or "must-have" situation.

This is a "it's worth spending $140 for a pair of Ubiquity Airgrids and if we get a working link, then maybe an extra $250 each for a pair of (X) network appliances (one at each site) to get the end result we want" situation.

So putting aside whether or not a working radio link is possible, I want to know that "X" is. What sort of network appliance do I need to add at either end of the link to create a single distributed lan (combining the lan at both sites) so all machines can "see" each other (192.168.2.x) and all machines have internet access through both the DSL connections distributed across both sites.

If the creation of a single distributed lan is a complicating factor, then bonding or joining of both DSL connections from the two sites that would be point of the excercise.