I'm about to move into a house with a couple of relatives and I was wondering what would be required to take two broadband connections and combine them into internet access for a single LAN. Specifically I intended to use two Comcast cable lines (likely a 6mbit and an 8mbit). I'm kind of curious as to how my external IP would work since the two lines would each have a different dynamic address. I could live with using one of the two connections for each computer, but I still need everything to come into a single LAN. If I could somehow combine both lines, then that would be even better.

I have an old Pentium 3 machine that I could slap a couple of NICs in and using for firewall/port forwarding purposes, but if a traditional router would work better that's fine too. I would need to familiarize myself more with Linux and hopefully use it on the firewall machine, although WinXP is a possibility. I intend to use wifi for three computers to connect, so I need to have that built in somewhere.

My network knowledge isn't all that extensive, but I have picked up things over the years, so I feel like I could probably implement most of the LAN except the outgoing connections. I have no idea about how to combine multiple internet connections into one outgoing line. Keep in mind that the dedicated firewall PC could be used with a third NIC if it could combine them somehow. And I probably can't afford to spend more than about $200 on new network hardware (excluding making my own cables).

Anyway, thanks for any suggestions ahead of time.

You need a router with dual WAN ports and load balancing. I have never done anything like this but that is pretty much what you need. I think you may be able to use the P3 box with Network Load Balancing on it but im not sure.

The Netgear FVS 538 is for a dual WAN input. But I think it's mainly for redundency, but I think it does load ballancing too. Atleast 1 to look at. They make another model with dual wans, but don't recall the model number.

DLink DI-LB604 is also another one that has it with QoS too. it runs about $150.

See this thread

I saw a thread a while back, The jist was to use 2 routers, with DHCP disabled. IP addresses were assigned manually. The default gateway for each computer would be set manually, according to router to handle the internet connection. (kind of like a static manual load balance)

example:
router1/Internet1 : LanIP 192.168.0.1 WanIP: (to match ISP)
router2/Internet2 : LanIP 192.168.0.2 WanIP: (to match ISP)
Computer1 : IP 192.168.0.100, subnet mask 255.255.255.0, default gateway 192.168.0.1
Computer2 : IP 192.168.0.101, subnet mask 255.255.255.0, default gateway 192.168.0.2
Computer3 : IP 192.168.0.101, subnet mask 255.255.255.0, default gateway 192.168.0.2

Computer1 would use the first internet connection, Computers2/3 would use the second internet connection. All PC would be able to 'see' each other.

Since you have that p3 I would suggest a linux distro (ubuntu comes to mind). No need to spend money on extra hardware you don't really need.

Try the following guide:
http://www.netlife.co.za/content/view/12/34/


Good luck

Why do you want to do that... both connections are on the same node... Once it's saturated during prime time, it doesn't matter how many connections you have, it'll still be slow. You're still sharing one upstream and one downstream so it doesn't make any sense to do this, unless your goal is tio get around the rate limiting they put on the cable modems.

Couple of things.

You can do this with Linux, or a dual WAN router.

HOWEVER, it probably won't work exactly the way you envision it. For true multilink functionality, both ends of the connection have to be set up for it, and you can bet your bottom dollar your ISP isn't going to do it for you.

What you can do with just a 2 port router is use the connections for redundancy, or per destination sharing. I don't know what the technical term for it is, but to do this on a Cisco router with two WAN connections, you'd use cisco express forwarding, and it offers per packet and per destination. Basically what that means is if you download a file from a website, it will max out one connection and the other will be idle. Now if you download another file, it will use the second connection.

Here's another HOWEVER... it works this way because web browsers use a single connection to grab the file and the router can't split that connection between the two WAN links. If you use a download manager, they usually use more than one, so that would allow you to use both connections. Apps like BitTorrent also work this way. Unfortunately, there's no way to bond the upstream connections because like you said, each connection will have it's own IP. Basically, it's not usually worth the effort to set it up this way unless you're doing it for redundancy. Maybe if you're constantly downloading huge files that max out your connection.

A better solution might be to see if you can get a single, faster, connection from your ISP for the same price as you pay for two different connections.

If you can set up a cable modem as one connection and DSL as the other you'll probably have better overall results as you'll hav two connections out versus having two cable modems that as soon as they leave your house merge into teh same line anyways.

Not true, A cable modem is typically capped at max speed. I don't know the exact number but I remember something like 45 mbit as a 'neighborhoods' bandwidth.

DSL on the other hand may not be capped, but rather limited by distance from the CO.

Some cable companies have higher speed options for business customers.

The maximum speed per neighborhood will vary based on provider, but it is typically much, much higher than 45 mbps. Most cable companies have a fiber ring that runs around the whole town, and they convert the fiber to coax to serve individual residences and businesses. The fiber backbone is at least 1Gbps, and many carriers have probably already upgraded to 10Gbps. This is typically irrevelant though, because the ISPs connection to the Internet is shared among all subscribers on their network, not just your neighborhood, so that's typically the true bottleneck.

The cable modem will be capped at whatever speed you pay for. However, you may have better results using different ISPs, say if it's 7PM and your cable service is crawling, the DSL may be faster. It's also much better for redundancy - if the cable goes down, the DSL is there as a failover.

They do NOT downconvert fiber for individual residences or business. They downconvert for a 'neighborhood', each neighborhood has a shared bandwidth of maybe about 45 mbps. A neighborhood may be a city block, 10 city blocks; depends upon how many subscribers, overbook ratios, etc. The 45 mbps is a number that I'm remembering off the top of my head and is the max that can be shoved down the coax pipe. It looks like 30 mbps is more realistic.

30mbps is theoretically the upper limit of DOCSIS equipment. And yes, I meant the fiber => coax conversion takes place at the headend which serves hundreds of subscribers. My point was that the back side of the head end is plugged in the carrier's fiber ring, so bandwidth to the head is a moot point, because a single head end is never going to saturate it.

It's true that people in geographic procimity to each other share the bandwidth of the single headend, but that limit is a lot more than 30mbps. The 30mbps limit is relevant to DOCSIS, that is to say, that's the most a single modem could have downstream, but I think that was just the initial spec, because there are providers offering > 30mbps on cable-type services these days.

I think the initial fear of cable because of the "shared bandwidth" came about years ago when the cable company's network was mostly coax and they'd have thousands of people on a single headend. This has mostly been eliminated with the new fiber networks being rolled out, which allow the cable company to bring huge bandwidth into individual neighborhoods. I typically don't see much difference in my speed between peak and nonpeak times.

From wikipedia:

I just saw this, I've never seen a DSL ISP that doesn't cap the users bandwidth. I'd agree that you might get less speed than what you pay for if you're far away from the CO, but I doubt you'd ever get *more*.

You are lucky...