Routers and Modems

Layer 3 forwarding capability

Connect networks\
- I might have two different switches with separate broadcast domains, and I'd have a router between them to allow them to communicate
  - Each side of the router would be different subnets and to communicate with the other subnet, you would move through a router.
Layer 3 forwarding
- IP addresses
Global reachability
Media Translation
- CAT5 or CAT6 cable, with our RJ45 connections everywhere in the building, the problem is that you got maximum distances. We would typically move to fiber optics.
- The routers capability is to be able to go from ethernet to something else.
  - If you have to go over Satellite or over a DSL circuit, you will find a router that could do this.
- Perform VPN
- Perform web applications

Modulator / Demodulator

Virtual Networks

On a switch we've got the ability to configure ports and this ports can participate in different networks
- For example: On a 24 port switch, ports 1-12 are for the Accounting department and ports 13-24 are for the Sales department.
Logically partition a switch into more parts.
- When you do this you also need different subnets.
- You will have to connect this different virtual networks through a router and go from one to another.
Virtual LANs (VLANs)
- Just means that we are going to take our physical switch and we are going to partition it by ports.
- If we have a Layer 3 switch we can route those different VLANs right there inside of the device.
Isolation by device, security, services, job role, etc.
- Demilitarized Zone (DMZ).
Fastest router under the sun
- These can move more layer 3 packets, they probably have so many interfaces.
Improves security
- We got parts of our network Isolated
No Wide Area Network (WAN) interface, no WAN capabilities.