Building a Large Network

[kxb177]

Looking to build a network in an off campus apartment building. I need to ultimately have 32 wired connections and two wireless access points. I want to power all of this with 4 cable modems. My question is what is the best way to do this. Is the answer as simple as getting 4 eight port routers and hooking them up each to a cable modem or is there a better way to proceed? I am also hesitant because I would rather have one network vs. 4, with the 4 solution people could not "share" across the network unless they were on the same one.

Thanks in advance.

-Ken

 

[nweaver]

You would have to find a load sharing router that supports 4 wan connections. That could be a little spendy.

 

[spidey07]

48 port layer3 switch is all you need.

although I don't think you'll be getting any increase in speed with 4 cable modems over a single one. don't know though...not my specialty.

you would setup the layer3 switch and have routed interfaces to the cable modems with a single default router. Then you could use per-packet load balancing across the 4 links.

Also a Large Network is generally considered over 10,000 nodes. Small is under 1000 and medium 1000-10,000

 

[ktwebb]

They could still share files. They'd have to be tied into a same switched network on the backend and problem use something other than IP, although you could still use IP's as well. You can have multiple IP's tied to a single card. I wouldn't exactly trust the dependancy of a setup like that however. I'd probably unbind NetBIOS to TCP/IP and install either NetBEUI or IPX/SPX for the local data flow.

On the other hand, Dual WAN routers can be had for soemthing like 150 or 200 bucks. Still doesn't solve your problem. One of the linux guys may come in here and recommend a multihomed Linux solution that could work for what you want to do.

 

[kxb177]

I am not necessarily looking for any speed increase, I am just looking that if I have 30 people on a once they are all not going off of one cable modem, as it would result in dial up speeds...

Also, I figured the routers (wired & wireless) could be had for a total of about $750....how much do these other solutions cost....

 

[blemoine]

4 cable modems?? how about a dual wan router with QoS. then you will only need 2 cable modems. what kind of speeds have you aquired from your cable company. if you talk to your cable company and get a business class service they can give you more bandwidth than what they are giving to Residential customers. our local cable company told me that they could go as high as 20 Mbp/s on a business line. that should be more than adequate for 32 users.

 

[nweaver]

I don't buy the 20 Mbp/s, as most cable modems are tied to 10 Mbp/s

For the cost, maybe you should consider dedicated lines, such as T1/T3 (t3 could get really spendy, T1 isn't too bad. I get 3/4'th T1 and 6 Voice lines for 300ish a month, iirc)

T1 may "sound" slow compared to the "3 Mb" hype, but really, dedicated B/W is awsome.

 

[spidey07]

well a T1 is slow as dirt compared to cable.

I routinely get 15+ Mbs compared to 1.5. The thing with bandwidth is its expensive...30 people IMHO don't need anymore than 10 megabits/sec. But then again I'm guessing this is college kids who demand to rape a pipe and feel they somehow deserve it.

Sounds like you are firming up your requirements a little. "provide adequate service to all for the lowest cost"

If this is the case you will need quality of service. I suggest a Layer3 switch with QoS ala cisco, foundry, extreme. Its a one box solution. Simple is good. Price will be 2-3K on the used market.

 

[randal]

I hooked up four cable modems as a single link one time at a LAN party. We had some network support from the IT folks at Adelphia, and with a simple ospf config, were breaking 30mbps without issue. I think we set a record for Adelphia internally or something ... they mentioned they had never done such a thing before.

 

[spidey07]

Originally posted by: randal
I hooked up four cable modems as a single link one time at a LAN party. We had some network support from the IT folks at Adelphia, and with a simple ospf config, were breaking 30mbps without issue. I think we set a record for Adelphia internally or something ... they mentioned they had never done such a thing before.

sweet. I was thinking more along the lines of the physical medium and how much it could push...the network gear could surely handle hundreds of Mbs, but the channel/cable plant was my concern.

Did you actually neighbor up with (OSPF) them and take their tables?

 

[Diaonic]

If your setting this up for a college I would also recommend getting a packeteer. This thing will save you timeless money and headaches.

 

[randal]

Originally posted by: spidey07

Originally posted by: randal
I hooked up four cable modems as a single link one time at a LAN party. We had some network support from the IT folks at Adelphia, and with a simple ospf config, were breaking 30mbps without issue. I think we set a record for Adelphia internally or something ... they mentioned they had never done such a thing before.

sweet. I was thinking more along the lines of the physical medium and how much it could push...the network gear could surely handle hundreds of Mbs, but the channel/cable plant was my concern.

Did you actually neighbor up with (OSPF) them and take their tables?

Unfortunately no. They made a stub for us, and we did standard equal cost multipath default routes across the links. We had tons and tons of little connections (websites, aim, irc, etc) for gamers, and only 10-20 large downloads going at a time, and with per-packet it really let everybody get as much as they could.

The physical layout was pretty conducive to the whole thing as well. The event was at a convention center and Adelphia has fiber to the facility. They have an OC3 coming into a Cisco CMTS (no idea what model, I'm not a cable guy) that connects to their HQ up north (direct area0 link). The CMTS then connected out to the conference room floor -- it was designed for having 200+ booths, all with individual cable modems, essentially creating a neighborhood in a big room. We just took four, hooked 'em up to a 6500, joined the stub and were ready to rock.

We were originally going to just use etherchannel to join the ports together on both ends, but the modems weren't transparent enough - didn't pass dot1q packets (MTU issue? Header parsing issues? Didn't waste time finding out). The cable modems went into the 6500 on the native VLAN, which also had eth0 of a FreeBSD traffic shaper attached. Then the 6500's other ports were the network core on another VLAN, which had the FreeBSD machine's eth1 attached. The BSD traffic shaper there filtered, managed, prioritized and NAT'd our internal networks appropriately, as I wasn't super-pro with Cisco QoS at the time.

That was 2 years ago? And I wasn't an OSPF guru by any stretch (still am not, learning more everyday), but that sounds right. We had ~650 gamers on it and it worked out great - even got accolades from several ESports commentator folks that the network was very snappy, which is apparently not standard fair at large events.

edit: edited for clarity

 

[Uncle Flappy]

Why 4 cable modems? Comcast/Cox Business Services can crank up the bandwidth to almost T-3 speeds. Check their websites for more info.

 

[blemoine]

Originally posted by: nweaver
I don't buy the 20 Mbp/s, as most cable modems are tied to 10 Mbp/s

For the cost, maybe you should consider dedicated lines, such as T1/T3 (t3 could get really spendy, T1 isn't too bad. I get 3/4'th T1 and 6 Voice lines for 300ish a month, iirc)

T1 may "sound" slow compared to the "3 Mb" hype, but really, dedicated B/W is awsome.

Actually for 20Mbp/s they said they run fiber up to the building and use a higher quality cable modem. a Motorola SB5100 supports up to 30Mbp/s so that would be a viable alternative to getting a T3 or multiple T1's

 

[randal]

Originally posted by: blemoine

Originally posted by: nweaver
I don't buy the 20 Mbp/s, as most cable modems are tied to 10 Mbp/s

For the cost, maybe you should consider dedicated lines, such as T1/T3 (t3 could get really spendy, T1 isn't too bad. I get 3/4'th T1 and 6 Voice lines for 300ish a month, iirc)

T1 may "sound" slow compared to the "3 Mb" hype, but really, dedicated B/W is awsome.

Actually for 20Mbp/s they said they run fiber up to the building and use a higher quality cable modem. a Motorola SB5100 supports up to 30Mbp/s so that would be a viable alternative to getting a T3 or multiple T1's

Wait a minute. They run fiber to a building AND install a CMTS to deliver the bandwidth on rg-58-60 coax instead of going straight cat5e/cat6/ds3-coax/fiber? That makes no sense. I know that hybrid fiber-coax buildouts are really popular, but for a single building?

 

[randal]

Originally posted by: Uncle Flappy
Why 4 cable modems? Comcast/Cox Business Services can crank up the bandwidth to almost T-3 speeds. Check their websites for more info.

I think that Adelphia's system was only able to provision 10mbps per modem, but it was full-duplex (docsis 1.1 I think). Not entirely sure, but we tried to get more out of one modem and it ran right up to ~10mbps ... maybe it wasn't a fastethernet port on the modem?