It's called a contention ratio and all ISP's operate some kind of model based on a contention ratio at some point in their network. If not at your DSL endpoint then further up the line at the link to the backbone.
Here in the UK a DSL connection is likely to be asynchronus at about 2Mbps down and 256Kbps up at a contention ratio of 20:1 meaning that your just sharing that internet bandwidth with 20 other connections. This as I said could be partly shared from DSL endpoint on the backhaul and partly shared at the internet POP. A 20:1 contention ratio is hardly noticeable if your primary use is browsing and basic email, If you start adding P2P, downloads, Big FTP traffic and Voip then 20:1 starts to really bite as your all trying to cram a lot along the pipe at the same time.
If you deploy at 10:1 at the prices you'll charge you can still turn a tidy profit but even better offer Synchronus service. Compared to DSL it'll be higher quality service and your customers won't be so tempted to leave when you get your system outages. And you will get down time. You may also be relying on customer premesis equipment to form down chain WDS links to other customers, If you lose a customer who's number 2 in the chain you have a problem when it comes to supplying down the line. In which case you may want to look at using a mesh topology instead.
But anyway, All the best in your enterprise and make sure you thank BrainSlayer for dd-WRT with a nice juicy donation each month when those subscriptions come rolling in.
Incidentaly when I first played with my WRT54GL I managed very useable bandwidth of 11Mbps at a LOS range of 2.7miles using standard antenna on the AP and used a linksys WUSB54GS usb client simple stuck to the car roof with duck tape. Watched DVD quality video from my server while talking to a colleague on Skype (With Video)
Joined: 07 Jun 2006 Posts: 980 Location: Coal Creek Canyon, Colorado
Posted: Tue Jul 18, 2006 22:27 Post subject: gird your loins...
wow this one bubbled back up to the top after quite a while... I guess I'll chime in now...
Our community co-op wisp now has 9 T1s ( 3 each bonded upstream from 3 locations ), a 5.8 MHz backhaul infrastructure, and 15 Accesspoints serving ~400 subscribers
We do use WRT54G units for member client routers ( mostly still alchemy, (sorry) but just lately (since SP1) some GLs on DD-WRT in pilot mode ) , but that's all.
we have orinoco (older) and WRAP/starOS (newer) for APs, and trangos for backhauls.
My idea is to move toward RB500 for PoPs ( B/G distribution and A+ backhaul - DD-driven of course...), but that's a ways off in 2.4-land , and I'm just one of many co-op volunteers....
Remember, the biggest monthly cost is NOT uplink fees, but support labor. Tracking down bandwidth Pigs, dealing with antenna allignment issues, swapping out lightening-addled components, etc.. gets to be a full time job after only a couple dozen subscribers.
You HAVE to design on the KISS principle ( Keep it STUPID-Simple ) or things get way out of hand fast.
Model different components for different functions and review the market constantly for products to fill each niche.
Don't ever put anything IN to service without a workable plan to take it OUT and replace it with something better.
Be super practical and try to stay sane - that's all I can add.... _________________ linksys GSv2, Gv4, Gv2, GLv1, G-TM, Buffalo wbr2, whr, whr-hp, whr-g125, wli-tx4-g54hp, Moto wr850gp, Alix.3C2
~100 people on a T1 is doable, but if any of them are "power users" (or indeed, anything other than "casual users"), darn near all of them will probably end up unhappy with you.
I'd strongly suggest that you consider adding some additional infrastructure; if not more bandwidth, at least a caching DNS server and a transparent proxy cache. Since a WRT won't hook (directly) to a T1, you're probably looking at a bigger piece of networking hardware in there somewhere anyway, and most "real" routers have built-in support for that sort of thing. (Cisco boxes with recent 12.x firmware can do this, even old 25xx ones.)
Talk to your ISP, see what they offer as filtering options to keep script kiddies out. See if they have an option for web space for you to resell to your users, because the last thing you want is to discover your bandwidth is getting eaten from the other side. (And it should go without saying that you need to replicate the webspace on your side of the link...)
If you're feeling really clever, you can do some judicious log analysis to figure out what the most common surfing destinations are, and write cron jobs to run during "off" hours to keep the cache warm. (Done right, it's methadone to the "more bandwidth!" H... Not nearly as good, but still a heck of a lot better than nothing.) And if you feel like being a touch antisocial, you can do a bit of filtering of stuff your users shouldn't be hitting. (Note: I'm not talking pr0n. I'm talking really obnoxious "hijack your web session" advertising.)
And if you're feeling like a _real_ b*****d, you can do traffic analysis and add a "most bandwidth used" scoreboard where all of your other users can see it. Alternately, you can put up a list of "1000 most recently loaded websites" - if you've got a web cache and a user community that surfs pr0n, you might as well encourage them to browse the _same_ pr0n. It'll save you bandwidth, and they'll be impressed by how fast it loads...
(Note to confused readers: I use the word "pr0n" to refer to anything that has a lot of extranious style elements relative to the amount of content it has. By my definition, cnn.com is "pr0n", while google is not.)
I have no experiance in this, and my guess is not many of you do either.
well I dont have experience as an ISP, but managing bandwidth supplied to large numbers of users I know all about. Looks like BG does too. At an office 90% of your traffic is going to be internal and perform the same no matter of your net connection. Your outside bandwidth is generally between your company's proxy and/or mail servers and the net. Those servers then serve inside clients via LAN.
My personal network has 4 users and net is fed by a 5mbps cable modem. None of us use torrent or p2p regularly, but there are some games. I pay $45/mo and expect that service for that price, but of course im in an area where I can get it...
If you want to give your customers 256/256 you would be looking at 6 customers to a T1 for a "fair share." There is a small amount of truth to your logic that not everyone is using it at once, but much more to BG's point of p2p. I wouldnt go more than 8 users on 1 T1 at 256/256.
And at that math you're still profiting 100% outside of non-bandwidth expenses.
90% of the cable companies use 100-150 users per T1.
When I worked at the school (still consult for two systems) we had over 300 per T1, the other school has about 700 with a bonded T1 @ 3mbps.
With the local cable company @ 139 customers with 1 T1 and the previously mentioned schools, I never had problems with download speeds that weren't related to the other site, aside from the magic 5pm problem, which seems to hit all broadband services aside from the rare situation of 3 people sharing a single T1. _________________ mmm... forbidden donut....
Some people sure are in lala land. The oversubscribe ratios being thrown around are pretty accurate...for 10 years ago as a dialup provider.
Your TYPICAL user these days is much much more of a BW hog. Everyone is using so much different crap, and you might as well accept 5-10% of your userbase will be permanently botnetted no matter how much you pester them.
Word of mouth will spread fast when you keep booting n banning joe homeuser who pays to have his computer cleaned a couple times. Even though its his 'fault' it gets reinfected over and over (fault meaning he runs windows and doesn't know anything about it) you'll be the one eating flak.
700 on 3mbps is sooooooo funny...just 100 online == 3.8k sec/ea before any overhead. On some days random internet backround noise to 100 public IPs will eat half that.
If you're rural and people have no choice, you'll get away with a lot though.
Check around with some ISP's. Typical is 100-150 per T1. If you have proper QoS to keep file sharing from hammering the network, its not a problem. _________________ mmm... forbidden donut....
