Ethernet LAN multiple DSL lines for single infrastructure

|----------->>> single switch <<<<---------|

> A friend with a small biz called and asked me a question
> about how he can increase bandwidth by adding a 2nd DSL line.
>
> He has a single DSL line, with a wireless router for laptops,
> and a 24-port switch for the office hardwired desktops.
> He wants to increase bandwidth by adding a 2nd DSL line,
> along with a 2nd wireless router.

> Now - the question - how to setup the infrastructure -
>
> Each wireless router will have a different SSID - so that is ok -
> BUT - how to handle the IP addressing between the 2 DSL routers...
> THINKING - split the single wireless router subnet,
> into two wireless router subnets - 192.168.10.x and 192.168.20.x
>
> HOWEVER -
> Can they both co-exist on the same Ethernet physical network
> and go thru the same Ethernet switch ?
>
> Each PC/laptop GW will point to each subnet's router,
> so that should be ok -
>
> But - since they are on the same "physical network"
> if I wanted to talk from a PC or laptop on .10 to a printer on .20
> will ARP's from the .20 have been recorded by the .10 PC,
> or am I always forced to go to the GW router for resolution.
> And, if I go to the router, will they have "seen" each others address,
> or will I need to manually add a static address for each other's subnet
> ?
>
> tnx for the discussion, comments, education -
>
>
> DSL line #1 DSL line #2
> DSL modem #1 DSL modem #2
> Wireless router (.10.1) Wireless router (.20.1)
> |
> |

> |----------->>> single switch <<<<---------|

> |
> |
> 192.168.10.100 192.168.20.100
> 192.168.10.101 192.168.20.101
> GW = 192.168.10.1 GW = 192.168.20.1

|>

|> ----------->>> single switch <<<<---------|

|>

> tnx for the comments about a dual port WAN router...
> We'll have to look into those, but then how is the price,

> and does each WAN port directly support DSL/PPPoE, etc ?

> Here was another network design that I thought off....
>
> Instead of having 2 subnets, and then having to setup a route between
> them,
> why not just keep ONE subnet, as the problem is just with the GW address
> to force 1/2 the traffic to each DSL line.... yeah, not load balanced,
> but cheap :)
> I wonder if this will work.... 192.168.1.xxx 255.255.255.0
> Take each router, and setup it's DHCP with a limited number of addresses
> (1/2 of the total), and with a unique range .100-.110 and .200-.210, but
> on the same subnet. Then, both will reply to any subnet DHCP request,
> and maybe 1/2 will be satisfied by each router. If not, then at least a
> stop-gap measure will be that each router will only serve up 1/2 of the
> PC's used. So, if say 20 PC's all try to get DHCP served, then 10 should
> be "forced" to each router by the limited DHCP reply and it's associated
> DHCP info (address, DNS, GW address).
> thoughts ?