Can You Use Cable and a T1 for Super Fast Internet?
June 29, 2006 8:37 AM   Subscribe

Can I Use a T1 Line AND a Cable Modem (wirelessly) for Super Fast Internet?

My building has several T1 lines for its residents, which I use to connect to the internet. It's fast, but at peak times when everyone's home it gets bogged down. The cable guy is coming today, and I can get cable internet set-up. It's faster, and always on.

My question is, can I keep my existing T1 connection (it's $20/month), connect to it through built-in ethernet (mac), AND, at the same time, connect to my cable modem through a wifi set-up, thus achiecing super fantastic speeds? Or can I have my computer constantly monitor which connection is faster and automatically have it use that connection for data?

Or do I just have to pick one or the other?

posted by bronxteacher to Technology (11 answers total)
The short answer is that it's possible... but if you have to ask if you can do it, then it's going to be way over your technical skill levels.
posted by Tacos Are Pretty Great at 8:44 AM on June 29, 2006

Yeah, it's definitely complicated to roll your own (I've done it, but only on a standalone PC, never a mac), although if you can find a box that does it all for you, it's (sorta) simple.

Note that especially with two providers (and still normally even with just one) you'll only get "twice" the speed if you are downloading two (or more) things quickly at once. You will not have any benefit for a single download, since the box will pick one of the two pipes to send the request down, it can't "split" each request. However, anything that uses multiple connections (eg: BitTorrent) will often (although, again, not always) benefit from the added bandwidth.

A quick google for "dual internet routers" turned up these twin routers that may or may not help. And here's a linksys model.
posted by shepd at 8:51 AM on June 29, 2006

This has been asked several times before (example). The short answer is no.
posted by cillit bang at 8:56 AM on June 29, 2006

shepd - how would BitTorrent would be helped by this? The tracker would only know about one of your two IPs.
posted by dmd at 9:03 AM on June 29, 2006

You're probably not going to find a good consumer-grade router that can handle this reliably.

Sure - it's possible - but do you really want to drop the change on a high(er) end cisco and learn how to program them?

I'm guessing no.
posted by jimmy0x52 at 9:09 AM on June 29, 2006

dmd, beats me, but it's been my experience that this does work. I'd find the snapshot I took once of my client getting 5.8 mbits download speed on the same torrent when I had 2 x 3 mbit DSLs.

My best guesses are:

- The distributed bittorrent service Azureus provides.

- My router randomly routed tracker updates through the two DSLs, sometimes the tracker got one IP and sometimes it got the other IP (and always ignored what my BT client said it was) causing other's BT clients to see mine twice.

- My router randomly sent requests for BT file sections (whatever the terminology is) from differing IPs. The clients on the other end were spooked, but not phased, at seeing random IPs asking for data, and just decided to send it out anyways.

Or so's my guess. I'm no BT expert! :-D
posted by shepd at 9:17 AM on June 29, 2006

Your cable modem will most likely be 2-3x (or better) the speed of the T1 line anyway.
posted by mrbill at 12:39 PM on June 29, 2006

Your cable modem will most likely be 2-3x (or better) the speed of the T1 line anyway.

Unless you're uploading...
posted by shivohum at 12:50 PM on June 29, 2006

Hah, was just doing this myself today...
posted by gus at 12:52 PM on June 29, 2006

Even if you could get it working, the programs you use might not be aware of it (unless it was transparent to them), so for example, firefox might use the same line that thunderbird uses, unaware that the other exists.
posted by hoborg at 2:32 PM on June 29, 2006

Seconding what others have said regarding channel bonding and multi-provider BGP routing; doing anything like this requires the knowledge and cooperation of the ISP's involved for proper routing, and cost and complexity wise is way beyond the casual home user.

What can work in such a set up, if you have the time and moxie, is to balance services to appropriate ISP's and combine this with some local caching of your own. For example, most cable systems are both highly asymmetric in upload speed, and pretty resource poor. Where I live, on Cablevision, the DHCP supplied DNS servers are typically 12 to 15 "hops" away, each "hop" taking a finite number of milliseconds to make on each DNS request, which request can only go out of my cable modem at an upstream rate of 256KB, against my download speed of 6 megs. Since everything I generally do on the Internet in a day depends on DNS resolutions, anything I can do to get faster DNS answers effectively makes things smoother and faster.

I suspect you'd find your T1 supplied service has "closer" DNS servers than your cable system will have (just due to the nature of cable system infrastructure), so, if you set up a local caching DNS server of your own, in front of your normal machine, and point it toward the T1 service for DNS requests, you'll get quicker responses. Machines on your internal LAN will be pointed to your own DNS machines, which will be getting its DNS info from the T1 provider, keeping DNS traffic off your cable connection. On the same local caching server as your local DNS is running, you could also run a Squid proxy for caching Web content, but have Squid pointed at the cable connection. In this situation, when you type a URL into your browser, your browser will send a DNS request to your local DNS server, and if it has the answer, your browser will get it immediately (microseconds on a 100 MB Ethernet LAN) and will send the http request to Squid to start getting the page over the cable connection, or serving it from Squid's cache if available. If your local DNS server can't supply the IP address, and has to send it up the line for resolution, at least you'll be getting it from the T1 provider, not the cable provider, and that will still be faster, and won't block cable download bandwidth for Web pages. For Web pages which have lots of linked images, requiring the browser to send out multiple DNS requests to build the page, the time "savings" can be substantial.

But there are some caveats, even for this approach. Generally, you still need some kind of separate box to set up the DNS cache (and Squid, if you're going to use that, too), and you have to have some understanding of setting up zoned DNS and Squid. Some cable companies will generally expect you to use DNS they provide, so that they can re-route you through their service proxies, and if you don't, some features of their service (internal email, customer service, etc.) may not work as expected.
posted by paulsc at 3:19 PM on June 29, 2006

« Older How do I come up with an hourly rate for a...   |   How to reinstal Car Door Panel? Newer »
This thread is closed to new comments.