Configuring a cable router and VOIP router in a home network

Posts: 20 · Vonage Forum Associate Joined: Sep 10, 2007 Posts: 20

I have a Motorola SBG900 cable modem/wireless 1-port router and a Motorola VT2442 VOIP modem/4-port router. I am trying to connect 1 wireless computer (to the SBG900) and 2 wired computers (to the VT2442). Currently, I have DHCP enabled on both routers and the VT2442 is plugged into the only port of the SBG900. Phone and internet work great, but the computers cannot see each other across the two LANs.

How can I configure my home network to get all devices on the same LAN and, if possible, to prioritize the VOIP traffic?

I couple possibilities: a network bridge (not sure what this is, if it's appropriate, or how to do it) or disable one of the 2 DHCP servers (not sure how to make this work - haven't tried).

Posts: 1123 · Vonage Forum **MVM** Joined: May 26, 2005 Posts: 1123

I vote for the easiest solution:

1) Disable DHCP in the VoIP router. Leave it on in the cable router.

2) Assign an IP address to the VoIP router in the same range as the cable router is supplying. (In other words, if the DHCP is handing out 192.168.1.X to everything, assign the VoIP router something like 192.168.1.50. That keeps it in the same network, but far enough away to prevent IP conflicts.)

Edit: I just looked up your cable router, and it does not have a built-in QOS function for prioritizing traffic. Check out a device called the HBB1 made by a company named Hawking. See if that would serve your purpose.

Posts: 20 · Vonage Forum Associate Joined: Sep 10, 2007 Posts: 20

The VoIP router is on the cable router subnet so it already has an appropriate IP assigned from the cable router's DHCP server.

My VoIP router has 3 LAN configuration options: 1) DHCP server, 2) DHCP relay, 3) DHCP disabled. I tried 2) DHCP relay and set the IP address of the relay to the cable router's IP. I got no connection from my computer (after VoIP router restart and computer NIC "repair") and had to configure a static IP to access the VoIP router.

Next, I tried 3) DHCP disabled on the VoIP router. Again, no connection from the computer when set to "automatically detect DHCP and DNS servers".

Am I missing something. Is the cable DHCP server (192.168.0.1) just supposed to detect my computer behind the VoIP router, which has an IP of 168.192.0.2, and assign a new IP to the computer, which then funnels traffic through the VoIP router?

Should I alter the cables in some way so that the computer does not have to go through the VoIP router?

Posts: 1 · New Forum Member Joined: Sep 11, 2007 Posts: 1

I am having a very similar problem and wish someone knew the solution. In my case, I have a 2-Wire wireless gateway as my DSL modem (2700HG-B Gateway), from that I have connected the Vonage Linksys RT31P2 router. Here are my link specs...

DSL line into the 2700HG-B
...DHCP on, IP set to 192.168.1.1
...first DHCP = .100, last DHCP - .200
...2 computers connect wirelessly to this router

from the 2700HG-B LAN port to the RT31P2 LAN port
...Internet Connection Type = "Obtain IP Automatically"
...Router IP = 192.168.1.2
...DHCP off
...NAT disabled
...1 computer hard wired to this router

Initially this seemed successful since I had dial tone on my phone. But then when I tried to connect to the internet from the hard wired machine (set to acquire IP via DHCP), no luck. I can only get internet access on this machine with IP set manually, but (interestingly enough) at the sacrifice of the Vonage connection (no dial tone). Seems it will only allow one or the other, not both.

I also tried the same configuration connecting the link from the 2700HG-B to the WAN port of the RT31R2, but this didn't work either.

Any suggestions?

Thanks!
Darren

Posts: 20 · Vonage Forum Associate Joined: Sep 10, 2007 Posts: 20

I currently have the following:

<li>Cable LAN w/ DHCP (192.168.0.1) to VoIP WAN (192.168.0.2) & Computer 1 (192.168.0.4) (wireless)
<li>VoIP LAN w/ DHCP (192.168.15.1) to Computer 2 (192.168.15.2) (wired)

Internet & phone work but computers don't talk.

I was going to try the following:

<li>Cable LAN w/ DHCP (192.168.0.1) to VoIP LAN & Computer 1 (192.168.0.4) (wireless)
<li>VoIP LAN to VoIP WAN (192.168.0.2) & VoIP LAN to Computer 2 (192.168.0.3) (wired)

This is only a guess. I'm sure the solution is relatively simple to some one who knows about networks. I'll let you know tomorrow if it works...

Posts: 4751 · Vonage Forum **MVM** Joined: Aug 30, 2005 Posts: 4751

The last configuration you proposed should work. You don't mention computer 3, but you have a 4th port on the VoIP router for it. You might want to look at Nate Hoy's writings here: http://vonage.nmhoy.net/tworouters.html . His configuration 3 is what you describe.

Posts: 4 · New Forum Member Joined: Sep 11, 2007 Posts: 4

Not sure about laptops but as far as desktops go, I have a cable modem with output to a Linksys WRTP54G with 4 pc ports and 2 voip phone ports. Nothing special needed for the phone. I did port forward some ports for specific applications but none for vonage. Using a 2 line desk phone

Posts: 20 · Vonage Forum Associate Joined: Sep 10, 2007 Posts: 20

Steve48 - Thanks! That worked like a charm.

The configuration is simple enough, it just was not familiar to me - I don't know much about routers.

What frustrates me is that Motorola tech support refused to help me (why would they? I'm only using 2 of their products!). And Motorola, Comcast, and Vonage do not have any support or whitepapers detailing a few simple different types of network configurations, such as in the link from Steve48.

Posts: 4751 · Vonage Forum **MVM** Joined: Aug 30, 2005 Posts: 4751

You're welcome. Nate's technical notes have helped a lot of folks. He hasn't been around for a couple of weeks now; let's hope he's back soon.