Running A Wireless Router Behind A Switch

[rdwing3000]

Wireless Router: Cisco Linksys Wireless N300 (single channel)
Switch: Netgear GS605 5 port gigabit
Modem: Arris sb6141 (not a modem/wireless router combo)

Okay, so, I've been reading through multiple threads about running a router behind a switch and I'm not sure the answers I've seen are making sense.

Everyone seems to be saying that it won't work cause the ISP will only assign one IP address and so only 1 device will be able to connect at a time.

And yet, I have just hooked up my switch in front of my wireless router and not only does my home wireless network have internet but my desktop PC, which is connected directly to the switch also has internet.

Background: The reason I wanted to try this setup is because I currently have an older wireless N router and the ports on the back are NOT gigabit ports. As a result, my desktop PC cannot take full advantage of my internet package (110mbps download)...I'm only getting 90-95mbps download due to the limitations of my router's ports.

However, my switch has gigabit ports on it. So, I hooked up my switch directly to the modem, then hard wired my PC into the switch and presto, I am getting 114mbps download to my desktop. I then hooked my wireless router to another port in the switch and so far I'm not having any issues getting internet on both devices at the same time.

**End of Background**

So I guess I don't understand why everyone says that this setup won't work...it's working for me.

A couple more questions:

1.) Is there a way to keep the download speed of the ports on the switch while at the same time making everything run on my internal network from the router? As of right now, my PC is getting an IP address from the modem but my wireless devices are getting their IP addresses from the router and so they can't directly communicate.

2.) Am I looking at any serious security concerns running my desktop PC off of a switch that's connected directly to the modem rather than behind my router? I do run anti-virus and my Windows firewall is always on.

3.) The only downside to this setup that I'm noticing so far is that my wireless speeds have dropped from 40-50mbps down to around 15mbps. This is with the wireless router behind my switch. Is this result expected? If so, is there any way to get the wireless speeds back up to what they were before I added the switch in front of the router?

 

[USAFRet]

Without reading the whole thing, it MUST be:
modem->router->switch->devices.

You have:
Modem->switch->router->devices.

The modem serves up one and only one IP address. To the first device it sees. Either a PC or router. The router then serves up internal IP addresses.
So...how many devices are hanging off the switch?

 

[rdwing3000]

I have 3 devices hanging off the switch: 1.) PC, 2.) Blu Ray Player, 3.) Wireless Router.

If it MUST be "modem->router->switch->devices" then how come I'm getting internet access on all 3 devices simultaneously with the setup of "modem->switch->PC, Blu Ray, Router"?

 

[USAFRet]

I have 3 devices hanging off the switch: 1.) PC, 2.) Blu Ray Player, 3.) Wireless Router.

If it MUST be "modem->router->switch->devices" then how come I'm getting internet access on all 3 devices simultaneously with the setup of "modem->switch->PC, Blu Ray, Router"?

That's a very good question.
A modem does not work like that.

 

[jsmithepa]

then how come I'm getting internet access on all 3 devices simultaneously with the setup of "modem->switch->PC, Blu Ray, Router"?

Maybe you found an ISP loop hole!

Post a picture of the back of the modem.

What are the IP addresses of the 3 ethernet devices? if they start with anything other than 10, 172, 192 they are WAN addresses and those devices are not going through a NAT and have no firewall, nakidd to the Internet.

If the ethernet IPs do start with 10, 172, or 192, they are NATed addresses and your "modem" is performing the function of a firewall/router.

Those are the known facts based on information provided.

Now lets say you don't want to go through all that trouble of figuring things out, I wager you have trouble having your ethernet devices talking to your WIFI device and/or vise versa. Normally I would say "whatever works dude." but not able to have ethernet talking to WIFI would not be acceptable to me.

 

[DeauteratedDog]

I did a little googling for the manual, which is pretty bad, but it looks like the sp6141 is not just a modem, but is a combination modem/router, however it does not include a wireless access point.

If you can reach the modem at http://192.168.100.1, look on the configuration tab, and you should see some information about the integrated DHCP server.

 

[rdwing3000]

Here's what is says on the modem's configuration page:



So does this mean that my modem is functioning as a non-wireless router? If so, then why does my computer's IP address start with "23." instead of "192.168.100.xxx"?

 

[USAFRet]

Here's what is says on the modem's configuration page:



So does this mean that my modem is functioning as a non-wireless router? If so, then why does my computer's IP address start with "23." instead of "192.168.100.xxx"?

Yes. It is serving up multiple internal IP addresses. Up to 32, apparently.

Why 23.xxx.....? Unknown. What does it say in the modem/router config?

 

[rdwing3000]

Yes. It is serving up multiple internal IP addresses. Up to 32, apparently.

Why 23.xxx.....? Unknown. What does it say in the modem/router config?

The modem config page there says that "these addresses are assigned from an address pool which begins with "192.168.100.11" and yet my desktop IP starts with "23."

Another question then, since we seem to have determined that this modem is also a sudo router....why would the download speed of my actual wireless router (which is connected to the switch) be transmitting only 10-15mbps download speed? The desktop is getting 114mbps. I would think that the wireless router should be pushing around 50mbps like it was before I introduced the switch.