Can a Catalyst 3560 L3 switch replace a router?

stevenrushing

I am CCNA certified, but it has been about a year since I certified and I just got my first job that I need to use my cisco knowledge with. I have a Catalyst 3560 L3 switch, and I need to know if I have to have a router between it and a satellite modem. We are putting together a transit case for oilfield satellite communication solutions, and I thought a L3 switch could be used as a router, but it has been so long and I don't remember how to do it or even if it is possible. Do I have to have a router between the modem and the switch, or can the switch act as a router?

networker050184

The switch has routing capabilities, but there are limitations. Does the modem hand off ethernet? Do you need NAT? Hard to really say without having all of the requirements.

krjay

Do you need NAT? Do you need serial interface? You need to know your requirements and compare the two devices.


edit: networker is a wizard with response time

stevenrushing

I need a device that would allow about 3 computers and 3 voip phones to utilize the satellite link. The hughesnet modem is actually hooked up to galaxy broadband, out of Canada, and provides a .252 address (so only 2 usable), and the switch or router has to use the only available address to talk to it. It then needs to share the connection with 3-10 computers or so, and 3 voip phones or so. Perhaps a point to point or point to multipoint radio later on.

networker050184

So sounds like you need NAT. That disqualifies the 3560.

f0rgiv3n

I recommend you pick up a firewall to be your device for this role. Who knows what that modem does if anything at all to block any incoming traffic.

shodown

I've done quite a few of these. Get a router with the security license or can firewall, one thing to watch for is how many VLANS they limit you to on the firewall which is controlled by licensing. I just did a install recently where the customer had all there traffic terminating on there ASA and have to purchase 15K more in gear to allow for a VoIP system. A costly mistake.

Corndork2

This sounds like the job for a Cisco 1841 + HWIC-4ESW or ASA 5505 (with license). Both are available for inexpensive prices in the used market.

As others have said, a Cisco Layer 3 switch (3550, 3560, 3750, etc) will not do the job due to the need for NAT.