[SOLVED] Ethernet selector + switch?

[ShaQBlogs]

I have 2 internet connections. When one goes down i would like to use the other one.
I am currently using this which is a manual switch with 2 in and 1 out. One of the two inputs can be selected and is sent to the output. This enables me to select one of the two internet connections to work with my devices.

However, what I need is a similar device which can have 2 inputs with 2 or 4 outputs instead of just 1 output.
Is such a device available? It can be either manual or auto switching.

 

[bill001g]

There are a couple ways to do this. You are using the brute force approach which I guess is simple.

I am not sure why you can't just hook a simple dumb switch to that box but maybe you need to explain better.

So option 1 which is slightly more advanced version of your method to do this.

Buy a 8 port or maybe larger if you need more ports, "smart" switch. A so called smart switch is a managed switch that you can configure. You need nothing fancy since you do not need any of the features, a example would be tplink sg108e.
What you would do is hook everything to this switch. You could then log into the switch and turn on/off the ports that go to the correct routers.

Like your current method this is not optimum because the router mac address will change and it takes a bit for the devices to figure this out.

Option 2 is to buy a dual wan router. There are many of these now days.

These routers in theory at least will detect the internet on your primary network is down and switch automatically. You can of course manually just force it to what every ISP you want.
They work ok but they aren't very smart when it comes to what "down" means. They for example would not switch just because a ISP suddenly got very slow or started have lots of packet loss but still mostly worked.
If you really work at it you to some extent can use both internet connections at the same time. This is much more complex than the router manufactures pretend. They for example have a load balance option but that seldom works well because your IP address would change and that will break many things.
What you can do is make only certain internal devices use ISP 1 and other use ISP 2. If you get a failure you can configure the router to run all connection over the ISP that is still functional.

 

[ShaQBlogs]

So option 1 which is slightly more advanced version of your method to do this.

Buy a 8 port or maybe larger if you need more ports, "smart" switch. A so called smart switch is a managed switch that you can configure. You need nothing fancy since you do not need any of the features, a example would be tplink sg108e.
What you would do is hook everything to this switch. You could then log into the switch and turn on/off the ports that go to the correct routers.

Like your current method this is not optimum because the router mac address will change and it takes a bit for the devices to figure this out.

Thanks for the reply. A few questions with regard to option 1, the smart switch.

1. I do not see a distinction between I/O ports. Are all ports functional as both input and output? Will it auto detect input and output devices?
2. With this smart switch how will i switch/select between the two input internet connections (These two connections come from two different ISP routers)?
3. You mentioned it takes a bit for the devices to figure out the change in mac address. Did you mean it will take a minute or two for the devices to function again when the internet switches from one connection to another?
4. You had also mentioned to use another switch along with the current passive switch. Were you referring to something like this?

I see an similar model here. Will this work?

 

[bill001g]

Yes that is good switch if it meets your needs. It in only 5 ports and only run maximum 100mbps. The big numbers in india prices always seem strange but in this case it looks like it priced about the same as the USA when you convert it.

A switch, even the cheap on you linked, can run every port at full speed in and out all at the same time. They have no concept of input devices and output. Logically it appears as if every device is directly connected to every other device.

When you use a smart switch what you are in effect doing is "unpluging" the cable to one of the router. Say you have port 1 and port 2 connected to the 2 different routers. You manually go in and turn off port 1 and turn on port 2. To use the other ISP you turn off port 2 and turn on port 1. Kinda like the button does on the box you have now just a little more complex.

Mac address issues will require a longer explanation but I will try to keep it simple. So let say you have both router set to 192.168.1.1......it is even more complex if you are using different IP addresses.
Your PC knows to send data to 192.168.1.1 to get to the internet. The thing is when you are on the LAN devices do not actually use IP addresses to pass traffic. When you tell a device to send traffic to 192.168.1.1 it looks in its ARP table to find the mac address. If it does not have this it sends out a broadcast message asking who has 192.168.1.1. Your router will respond telling its mac address. The pc then caches this in the ARP table so it does not have to ask every time it want to send data. Many devices this is held 5 minutes or more before it will ask again.

So when your device has the mac address it will send data that it want to go to the router to that mac address. All works well. BUT now you change the device that is called 192.168.1.1. The end device still has the old mac address in the ARP table. So when it want to send data to the router it uses the old mac address but there is no device on the network with the mac address so the packet just gets deleted. How long it takes for the end device to figure this out varies a bit. Worst case you have to wait until the ARP table entry times out. Most time the end device will figure out something is wrong and send out a new ARP message and it will then be told the correct mac by the new router. The exact details of how this works vary greatly between devices.

Now you the human are smarter than the device and you can use the command ARP -d * to clear the ARP table and force the device to ask for the new mac address immediately.

 

[ShaQBlogs]

With the smart switch i guess i cant go wrong. Worst case I use the manual switch to toggle the ISP's.

What is the difference between the TP link sg108 d/e/s?

 

[bill001g]

tplink is pain with their part numbers are they like to change them for no reason it seams.

They like to call lots of switches 108.

They have 2 major lines of switches. The ones they target at end consumers and the switches they sell to business and home users with more advanced needs.

The 108 with no letters is the base consumer, the one with 108s is some silly green power save things, the 108d I think is actually the 1008d. This is a switch that comes with a plastic rather than a metal case, it might be cheaper.

The "e" models are the lowest end business switch but are still very powerful and support all kinds of stuff like vlans and port bonding. You are going to use the most simple feature to enable or disable a port.

They have a bunch of other letter that mean things like if it support PoE and if it can be rack mounted.

You can find many other brands that have similar abilities. The tplink sg108e tends to be the cheapest one and it has a metal case. Although it doesn't matter in your case make sure you get hardware revision above v3, the current is v6 so if you buy new that is what you will get. They had a strange vlan design flaw in the early hardware versions.