Hey, I have an RCA cable modem here, and in a few weeks I will be building a LAN on it. I need to know if my modem (model DCM215) has a built in router so I can add a hub, or if it needs an external router first?

Ill be back in four days from Santa Fe, new Mexico, pls keep this topic close to the top so I can find it....thx.

most cable modems wont have a router built-in, I would be very suprised if yours does.

If you are allowed more than one IP from your ISP you *could* plug the modem into the uplink port on your hub and network it that way but I dont recommend that.

here are some links about that modem:
http://www.thomson-broadband.com/products/spec.pdf
http://www.cable-modems.org/gallery/


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cEnsE
evil, corruption and bad taste

Blah, RCA modem. At least you're not hooked up USB.

It's not a routing modem. (If it was, you'd see ports for multiple computers to hook in, not just the one.) Buy a Linksys router. Nothing more to say, really.

You can probably find some used Cisco routers cheap, the ones that needed the software patch for Code Red.

I don't know if this is what you need though.

if hes asking about a built in router i doubt he needs cisco level gear but if you can score it cheap its a decent idea. like spiffy said just buy a linksysy four port router for a hundred bucks.

*do not but netgear*
they suck and the support is pathetic. when my pcmcia netowrk card didnt work i got a tech that couldnt even speak english three different times. it never did work and no one ever helped me.

I've got a cisco 2501 I'll sell you

w00t. I'd be up for that. However, judging from your location I bet the mail is gonna cost half of a brand new router. 8) I'm in the central US.

BTW, who exactly isnt it a good idea to just hook the router into a hub and run it? I know my friend did that for a while and it worked fine.

seems like it should work fine to me. Course I don't know how that particular router would handle that, but its worth a shot

quote:

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Originally posted by Dr Spock:
BTW, who exactly isnt it a good idea to just hook the router into a hub and run it? I know my friend did that for a while and it worked fine.

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As long as the router's got an uplink port, it should be easy.. it's just a question of, do you really need to do it?

Routers dont have uplink ports persay, all ethernet ports on a standard router are wired the same as the port on your NIC. Its just like plugging in another computer to the hub.

In almost every standard LAN setup there are routers plugged directly into switches, maybe a router-on-a-stick (ROAST) setup or two or more connections to the switch for every subnet or VLAN.

I dont understand whats the problem with hooking a router up to a hub is... other than hubs are just crap anyways, use a switch.

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cEnsE
evil, corruption and bad taste

My applogies, I screwed up. I mean putting the modem cable which usualy goes to the NIC directly to a 4 port hub and then hooking 2 comps to the hub.

Sorry about that.

That could cause problems and thus, I dont recommend it. You would have to plug that cable into the uplink port on your hub for it to technically work.

For it to realistically work, you have to do the above and be sure that your cable provider will assign you more than one IP. Each machine hooked up to that hub will require a real IP address as there would be no router doing NAT (PAT) for you. I am unsure of what happens if you are only allowed one IP from the provider, I assume only one machine would have connectivity at a time.

I DO NOT recommend that kind of setup anyways. When all people are using the connection, you will have many many collisions, thus slowing down the connection and you will have a harder time securing things up.

I DO recommend a router.

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cEnsE

Ok thanks, Ill end the questions here then. Just for posterity, my friend ran that setup on ATT @ home. The result was 2 computers which ran fine on the shared hub, but both had the same IP. It was a different modem than mine, but the same service.

If both machines had the same IP then they could not communicate with each other... and thats basically a defeating the purpose of networking.

Also, each machine would be recieving the replies from requests sent by just one of the machines, slowing them both down and possibly messing things up if they are both lets say... surfing the same site ?possibly?

It seems against all things thats ive learnt in networking to say that 2 machines having the same IP and being networked will work properly but maybe there is some catch i dont know about.

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cEnsE

It would barely work, if at all. The collisions on the the mini network would be so intense as to downgrade the DSL to a 56k capacity at best. Either set up a *nix box as a gateway, or buy one of the premade routers. I know this is totally contradicting my previous post, but hey, I fucked up.

Just plugging the modem into a hub with other computers will work, with a few tweaks. I've got my DSL modem hooked to the uplink on my cheap-ass Linksys hub. Three 'puters are plugged into the other ports of the hub. My main win2k machine VPNs the modem to connect. It's running NAT software to provide service to the other computers, so I only have to pay for one public IP. If that machine is down, the other computers can still connect (one at a time) to the modem. Even with the hub chopping up the bandwidth like that, there's more than enough room for 1.5Mbs 'net flow...

Not sure if this'll help you, though. The way I have to tunnel to the modem is one of the less common connection methods, but then I'm on this bizarre PPP over ATM protocol. If I could afford it, though, I would have a switch and a dedicated router or a *nix gateway. Good luck.

Thx, I dont know if he could transfer files or not, but I know he played a mean game of counterstrike with a friend there. It was odd joining your own IP, but they both could play the same game without too much lag.

It seems ill be getting the router tho...I dont screw with my comps unless they are cheap or worthless to me.

BTW what does it take to be a regular instead of a member?

nm.