Here is my existing layout:
CompanyNetwork -- MetroE -- (Fa)Router(Fa) -- switch -- InternalLan
Both Fastethernet intefaces in the router are taken, one is being used for the MetroE, the other one is for the internal vlan.
We are planning to install a separate internet T1 so we can take this person off the network (this is a private property). It will be a manage router from AT&T. This ISP router connects to a Fastethernet interface but both are taken. The switch is connected to the router using trunking and has two vlans, voice and data. No other configuration.
I have two scenarios:
1. Buy a High Speed Fa card (very expensive) for the router to connect the ISP router in there.
2. Connect the ISP router into the switch.
Which will you choose?
You could also buy (depending on your router) a HWIC Ethernet module. Much cheaper than an FE interface on a router or layer 3 image on a switch.
Hope that helps
If cost if the major criteria, and if you're already trunking vlans between the router and the switch, and assuming there's a spare port on the switch, connect the new ISP router to the switch and configure a new VLAN on that port that's also trunked, on the existing trunk, to the router. Of course, bringing traffic onto the switch via a VLAN, some consider a security issue. Also, as with the other Ethernet subinterfaces on the router, you might be unable to implement some IOS feature that you could with a dedicated port.
I would go for HWIC-4ESW.
Or else if you have a spare serial interface you can go for serial to ethernet converters.