SG300 and multiple WAN connections

[michaelfrankel]

Currently I have my SG300 connected to a Wireless Router which is, in turn, connected to a Cable Modem.

I'm considering adding a second cable modem. Can the SG300 handle that?

[Tom Watts]

Hi Michael the SG300 can handle at least 100 users without much problem.  The SG300 cannot NAT so if the second modem / router connections it should do that function. Only difference would be you should probably create a vlan to separate the first internet connection from the second internet connection otherwise you may get some hairy network behavior.

-Tom
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[michaelfrankel]

The cable modem I have does NAPT (a form of NAT), so that's not an issue. Since the current modem is already acting as DHCP server, I can turn off DHCP on the second one or have be a DHCP server for a different subnet.

The VLAN thing, however, is not really clear to me yet. I've looked that the Web managment utility for

the switch and read the documentation. It brings up more questions than answers, and I'm still not sure it will do what I want, which is provide me with double the bandwidth.

Additionally, if I do set-up 2 VLANs, will this segment my network such that computers on VLAN 1 will not communicate with VLAN 2? This is not what I'm after...

[Tom Watts]

It depends what you're after. Does your router support 2 WAN connections? Or will these be a scenario you're using 2 different routers?

You can't really have 2 different internet gateways on the same LAN unless you have something to manage the internet connections. The switch isn't going to load balance those connections for you. The switch can separate traffic through vlans and subnets.

You could possible set up static routes on each gateway device to point to the LAN IP of the other device which could make them aware to route traffic between 2 different subnet IP.

Your challenge is going to be the fact if you want 2 different internet gateway on the same LAN, you need to make sure the default gateway of the desired computers are using that of the router you want internet traffic through. Then this still leaves the complications of things like DHCP.

Another very creative thought may be to set the switch in layer 3 mode then create 2 subnet and have the switch service DHCP for the 2 vlans. This would get the intervlan communication anyway... But I wouldn't be sure how it would behave when it comes to the internet requests, but I suspect it should stay within its own LAN when it came to that point.

-Tom
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