Computer Networking oddity...

[Isak]

Hey everyone!

I know there's a few somewhat computer savvy Playgrounders... So I've come seeking some help.

A while back, I got a D-Link wireless router... a DIR-825 to be exact. At the time, we had a slower DSL connection, and it totally destroyed all of our bandwith.

Recently, we upgraded to Comcast; and I just recently got around to setting it up and seeing how it works. The software itself has been misplaced/disappeared; so I've been working with the latest firmware update directly from D-Link.

So, Here's the layout.

Connected directly to the cable modem (A) is a switch(B); Connected to a router(C) and three lines(B2/3/4) leading off of it. One of these lines leads into my room; where it plugs into my DIR-825. The other router (C), leads lines downstairs, and upstairs to my Sisters room.

Back to my router. Currently, I have two lines plugged into it. One leads to my Xbox; the other to my computer.

As far as physical networking goes; That's how the currently set-up is. Wirelessly, It IS working as far as I can tell (My iPod connects to it without issue, however the signal strength is pretty weak...)

Now onto my problem, after that lengthy description of the set-up...

My Router is indicating that it IS getting a good signal from the modem, and that the signal IS being shared between the Xbox and my computer... Problem is; My computer isn't getting internet, but IS reading the network (It won't let me access any shared files, however). The Xbox's connection is running excellent.

If you aren't completely lost at this point; What would you recommend trying? I've attempted multiple hard-resets of the Router, reinstalling the firmware (Factory shipped versions, as well as the most up-to-date). I'm tempted to try connecting the DIR-825 directly to the Comcast connection... But that's what we did originally with the DSL and it killed our connection speeds... Instead of the 150kbps we were getting; The top we'd get was about 10-15...

Hopefully someone can help me...:smallbiggrin:

[Zorander]

If I understand you correctly, you have at least 2 routers on your network, maybe 3. The first thing I would check is for an IP conflict. Your D-Link router may be sending the same network IPs to your computer as either router C or perhaps the Comcast modem (which generally tends to be a router also, especially since you state there is a switch between the Comcast modem and router C). Did Comcast set up the switch and router C?

[Anasazi]

its actually not that, one of the differences between a switch and a router is how it assigns IP's, which is based on how they transfer data. a switch establishes an individual IP address to all machines connected to it and broadcasts those outside the network, this ensures maximum speed for data packets to the machine they're ment to be connected to, instead of just sending all packets to the entire network. However, this also requires a seperate external IP to be accessed by your ISP (comcast in this case). Which is fine if you're only trying to connect, its either 3 or 4 machines with comcast, to the internet. For gaming, using a switch is preferred unless you have a large network, then it starts getting in the way.

You have a couple of options, comcast allows you to purchase additional IP's to use with the switch, i believe its like 5/month for an additional 10 or something like that.
Or, a much better option, is to setup the switch in a different part of the network, ie, the networking device connected to the modem should be a router. the further away from a direct connect to the router with that switch the better, as it will be limiting less and less machines with that route. And actually, considering how many connections you have in that house, its probably time to adjust the network anyways and get yourself a 10 connection router to plug directly into the modem, and keep the switch for lan sessions and the like.

[Zeb The Troll]

its actually not that, one of the differences between a switch and a router is how it assigns IP's, which is based on how they transfer data. a switch establishes an individual IP address to all machines connected to it and broadcasts those outside the network, this ensures maximum speed for data packets to the machine they're ment to be connected to, instead of just sending all packets to the entire network. However, this also requires a seperate external IP to be accessed by your ISP (comcast in this case). Which is fine if you're only trying to connect, its either 3 or 4 machines with comcast, to the internet. For gaming, using a switch is preferred unless you have a large network, then it starts getting in the way.Well, typically a switch doesn't assign IP addresses at all, though a typical home router will.

I've had Comcast and Verizon and neither of them have limited (that I've been able to hit, anyway) the number of devices on my side of the modem. (I currently have a desktop, a laptop, a netbook, an Xbox, and a Wii connected at all times, with two additional laptops that visit frequently and I've had even more when out of town company arrives as well.)

At a glance, I'm inclined to agree with Zorander's assessment, that you probably have more than one device configured as a DHCP server handing out IP addresses without talking to each other first.

The easiest option to fix this is to limit the number of routers on the network (one is optimal for a home network). You should be able to connect one of your routers to the modem (unless your modem is also a router), the switch to the router (if it's even needed) and run your lines from there. A wireless router is typically capable of supplying all wireless needs in a normal home from a central location, so maybe your D-Link would be a good choice for this.

If you must use your additional router(s) to make things work, make sure that only the one directly connected to the modem (or the modem itself if it is a router also) is configured to hand out IP addresses and use the other(s) as smart switch(es) only.

[Anasazi]

Either way, we might not agree on whats causing the issue, but we agree on the same solution. Isak, change out the location of your switch.

I would like to note though, all ISP's limit the number of external IP's you have, routers use one ip and assign internal IP's to the devices connected to them. Switches pass through the external IP to the machines its connected to. Both work relatively the same, or rather can be used for the same sort of thing (networking), until you incorporate a modem into the picture and start assigning IP's. Why is this any different? because thats when restricted access comes into play. All dynamic IP ranges are registered to a location and a person/company, if you try to use a static ip outside the range of your dynamic ip range, what happens? nothing, because you are forbidden from using IP's outside your range.

[Zeb The Troll]

Either way, we might not agree on whats causing the issue, but we agree on the same solution. Isak, change out the location of your switch.I had a much longer post ready, but suffice to say that I disagree with this assessment. The problem, as I see it, has little or nothing to do with the location of the switch and everything to do with the number of routers and how they are likely to be configured from the factory.

[Anasazi]

You should be able to connect one of your routers to the modem (unless your modem is also a router), the switch to the router (if it's even needed) and run your lines from there.

Then why suggest otherwise? Such a solution IS changing the location of the switch.
I'm not ignorant to your point of view, I too am CCNA, I just happen to have a different perspective on it than you.

[Zeb The Troll]

Then why suggest otherwise? Such a solution IS changing the location of the switch.
I'm not ignorant to your point of view, I too am CCNA, I just happen to have a different perspective on it than you.Simply, the location of the switch, in my view, is not the problem. I mentioned the location of the switch only as a matter of a more logical home network setup, if it's even necessary, and mention of it at all is only incidental to reorganizing existing equipment. If, like most ISP's these days, the modem provided is also a router, then the switch need not be moved at all. You're reading far too much in to my passing mention of it. Or to put it more simply, I don't think relocating the switch by itself will resolve anything. I didn't mention it as part of my solution, only discussing a logical placement for it if it's needed at all.

I don't know how to more strongly iterate that the switch is not likely to be the problem in the existing setup. Since you're a networking professional, you might also note that my problem is not with routers, per se, but with with too many DHCP servers (an additional role filled by many residential routers that is not their primary purpose in a network at all). Bearing this in mind, it is entirely possible that the problem could be resolved simply by turning off DHCP on all but one of the routers and rebooting everything. But since we're offering assistance, I thought it might be useful to provide a more organized structure to the existing network as well.

[Zovc]

It definitely would be best if there was a router connected directly to the modem.

I think the best place for the switch will be in your room.

Having two routers on a network can cause problems, and you should make sure they aren't both trying to be 192.168.1.1, the usual IP for a router to have statically assigned.

See if either of your routers can be configured to function as a switch, that would probably keep complications to a minimum.