How to combine two ISP network?

Question

I want to experiment combining Cable Internet with AT&T U-verse twisted pair Internet.

So basically,

1. AT&T U-verse was very reliable, but only gets about 25Mbps
2. Comcast can go up to 1200Mbps, but in the past sometimes there was outage for a few hours

So if I subscribe to both services at home, now I have two modems / routers box from each ISP. In this case, how can I "merge" the two networks, so that computer 1 that is connected to AT&T can talk to computer 2 as if they are on the same LAN?

P.S. perhaps one solution is to create a merged LAN, and what if a notebook is connected to LAN 1 by Wifi, and connected to LAN 2 by using a USB hub that has an Ethernet port? Then can this notebook be connected to both LANs at the same time? (but this solution forces any computer to use an extra Ethernet port and cable).

P.P.S or if I let the NAS connect to both LANs (if the NAS has two Ethernet ports), so would that mean all computers can connect to the NAS? So even though the computers are not on the same LAN, they can save or read files to that same NAS, and it is good enough. (just that computer on LAN1 cannot access another computer on LAN2 which is running a web server, but I think this is less important).

Answer 1

There is no simple, cheap one-size fits all solution here, and it really depends on what tradeoffs you want to make. A couple of possible solutions -

Get yourself a router that load balances between the connections. If both your ISP's deliver to you over ethernet, then you can maybe get rid of your ISP boxes, otherwise you would want to put this new load balancing router between your network and your boxes. (Of-course, this makes the new router a single point of failure). To find an appropriate router, maybe start with a Google search "dual wan router" or "load balancing ethernet router". This is probably the better solution as it will allow for load balancing and automatic failover, but will have a cost associated with it.

Another possibility would be for you to have 1 network with both connections. You may be able to use subnetting and a combination static IP and dynamic IP addresses to load balance your usage so some devices go out 1 connection, others go out the other connection, but both devices are on a LAN. Possibly as follows (there are lots of different variances of this):

• Set router 1 with an IP of 10.0.1.254 netmask 255.0.0.0
• Set router 2 with an IP of 10.0.2.254 netmask 255.0.0.0

Ensure that the DHCP server is turned OFF on router 2.

Any new device plugged into the network should get an IP in the range 10.0.1.x through DHCP from router 1.

Any device you want to use router 2, set up with a static IP address in the 10.0.2.x range and default gateway of 10.0.2.254 (and maybe use 1.1.1.1 as nameserver)

Because you have a netmask of 255.0.0.0, computers on the LAN will be able to see each other because they are all between 10.0.0.0 and 10.255.255.255.

Of-course this has the disadvantage of half your network not working if the connection goes down.

It is important you only have 1 DHCP server on a LAN [segment]