multiple DSL lines for single infrastructure

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

From: "Phil Schuman"

| 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

$150 and up.

Yes. They're designed specifically for that purpose.

That's not going to force traffic to either line, it's just going to give you messy DHCP. to make it work, you will probably need to lock IP addresses to MAC addresses, which pretty much defeats the purpose of DHCP.

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 ?

If 10 PCs receive the GW address as 192.168.1.1 and 10 PCs receive the GW address as 192.168.1.2 then each "logical group" will use "their" GW and DSL line. Yeah - it's not load balanced, but merely spliting the infrastructure between 2 lines - a roll of the DHCP dice - I know multiple GWs work, as we did it with our T1s and ISDN, and also used multiple DHCP servers - with non-overlapping scopes.