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I have two stores in two different sides of the same street, Each one has an ADSL connection with a wireless router and a different IP address.

So I have two different wireless networks connected to the Internet separately.

I want to share these networks so that when one ADSL router is disconnected from the Internet it will connect to the other network wirelessly to keep the connection.

I want the networks to be connected 24/7 in both the stores, and in case of ADSL problems in one of the networks, the other network will back it up.

I can't connect a cable between the stores, because there is a road between them.

How can I configure the routers to share my networks?

EDIT: The reason I'm asking this question:

I have two CCTV systems with DVRs, one in each store. Each is connected to its own router, and I want them both to be online even when one internet connection is lost.

This way I can always connect to the CCTV of both stores using my phone or home computer and know that everything is OK...

The solution of creating one wireless network seems good, but I need the DVRs to work on both networks, so I need the routers to connect to each other wirelessly (is that a word?).

I would also accept a solution involved with changing my hardware.

Thanks...

Shahar
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3 Answers3

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Sounds like you want a routing based on availablilty of the uplink to the provider.

(The availability of the WiFi is already handled by normal procedures. If one goes down and your client knows both WiFis it just connects to a different one.)

What you want is:

Two Internet connections <-INTERNAL-CONNECTION-> Router <-INTERNAL-CONNECTION #2-> Clients

The router can determine if an internet connection is up and offer a secondary backup. The internal connections can be everything.

Example:

DSL#1 <-> Cable <-> SingleAndOnlyRouter <-> CableOrWiFi <-> ClientInHouse#1
DSL#2 <-> WiFi <-> SingleAndOnlyRouter <-> WiFi <-> ClientInHouse#2

Of course there are other possibilities, but this would give you the flexibility you need.

Probably there are off the shelve components to do this (can't help you here), or you can setup your own "routing" server (Linux/BSD/Unix or Windows).

Your DVR would be a one possibilitity of a client. Like this:

DSL#1 <-> Cable <-> SingleAndOnlyRouter <-> CableOrWiFi <-> DVR#1
DSL#2 <-> WiFi <-> SingleAndOnlyRouter <-> WiFi <-> DVR#2

Both use the same internal network in this example (although the setup could even be improved there, but seems like a little overkill). The router will recognize when one DSL line is down and alternatively use the second.

It is also possible to use both in parallel so automatically a lost uplink will be transferred to second uplink (Example).

I did a quick research for components offering the routing possibility out of the box (not setting up your own server): Cisco/Linksys offers it.

harrymc offered a cool link for this in his answer:
http://www.smallnetbuilder.com/finders/router/products

StampedeXV
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You could use a multi-WAN router, one that does automatic fail-over.

To get some idea as regarding candidate routers, you can use the Router Finder, and click the WAN Ports link twice in the Features section to sort by descending number of ports.

This finder does not list Draytek routers, and I have heard good opinions regarding fail-over for the Draytek Vigor 2920. Also for Cisco RV0XX routers.

For a router that supports DD-WRT, this firmware can also do Dual WAN with failover, although some script-writing is required.

Fail-over is not instantaneous and may take a few seconds, depending on the test-frequency built-into the router. When the switch happens, any existing connection will be disconnected since the router will shift from one IP address to another. If you change ISP, this can be even slower.

harrymc
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Check that your 2 wireless routers are wirelessly accessibles from the other side of your street.

If this wireless point is OK just configure your 2 wireless routers:

  1. So as to broadcast the same wireless network name (SSID).
  2. So as to use separated channels. Most notably if you want to accept 802.11b or 802.11g clients, take care to choose 2 channels separated by 3 (example: 1, 5).
  3. As DHCP servers on the wireless side (only) and so as:
    • to use the same IP addresses range if your 2 routers see each other (on the wireless side, correct DHCP servers will manage this without any other abnormal configuration), for example : 192.168.0.0/24 or 192.168.0.0 → 192.168.0.255),
    • to use separated IP addresses ranges if your 2 routers won't see each other, for example : 192.168.0.0/24 (192.168.0.0 → 192.168.0.255) & 192.168.1.0/24 (192.168.1.0 → 192.168.1.255).

Your clients will switch from one router to the other:

  1. If one of your routers fails.
  2. If there are too much interferences to reach one of them.
  3. If one of them is overloaded with wireless clients.
athena
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