[Day 10] 9. WAN Infrastructure

1. Local Loop (Last Mile): This refers to the physical connection between the telecommunications provider’s network and the end user’s premises. It’s called "last mile" because it typically represents the final segment of the network that delivers service to homes or businesses.

2. CPE (Customer Premises Equipment): This includes devices located on the customer’s side of the demarcation point, such as routers, modems, and switches. CPE connects the local loop to the customer’s internal network.

3. Demarc (Demarcation Point): This is the point at which the service provider’s network ends and the customer’s network begins. It’s where the provider’s responsibility ends, and the customer’s responsibility begins. The demarc is often located at a wall jack or a specific piece of equipment.

4. CO (Central Office): This is a facility used by a telecommunications provider to house equipment that connects calls and manages the network. The CO aggregates signals from multiple local loops and connects them to larger networks.

5. POP (Point of Presence): This is a physical location that houses network equipment and interconnections. POPs provide access to the larger internet and may connect to various networks, allowing data to be routed efficiently. They can serve as aggregation points for traffic coming from multiple local loops.

6. Toll: This term generally refers to long-distance charges associated with WAN services. It can also relate to toll-free services or pricing structures for transmitting data over longer distances.

Diagram in book.

How They Work Together:

• Local Loop connects the end user to the CPE, allowing customers to access the network.
• The CPE connects to the demarc, which serves as the boundary between the customer’s network and the service provider’s network.
• From the demarc, signals travel to the CO, where they are aggregated and managed.
• The CO connects to various POPs, enabling data to be routed across wider networks, including the internet.
• Toll charges may apply for data transmission over these distances, especially when using long-distance connections.

Together, these components create a seamless infrastructure that allows users to access WAN services and the internet.