Certainly, let's dive into the scenario you've presented and explore the concept of Wide Area Networks (WANs):

Growing Company Network Scenario:

• You are the sole IT support specialist in a small company with a few employees and computers in a single office.
• You implement non-routable address space for internal IPs to conserve IP addresses and set up a router for NAT.
• Local DNS server and DHCP server are configured to ease network configuration.
• You contract an ISP to provide internet access to the office.
• As the company grows, you set up a VPN server for remote access to resources, enabling salespeople to connect from different locations.

Expanding to a Second Office and WAN Technologies:

• The company decides to open a new office in another city across the country.
• Wide Area Networks (WANs) come into play to connect the two offices, forming a single network spanning multiple physical locations.
• WAN technologies involve contracting a link across the Internet with an ISP to transmit data between sites.

Key Concepts in WAN Implementation:

• Each network of computers in different locations connects to the ISP's network at a demarcation point.

• Decramation point is physical point at which a service provider's responsibility for a network connection ends and the customer's responsibility begins.

• The area between the demarcation point and the ISP's core network is referred to as a local loop.

  

• Local loop technologies can include T carrier lines or high-speed optical connections to the provider's regional office.

• The ISP's core network connects to the broader Internet, enabling data transmission between different office locations.

WAN Protocols:

• WANs use various protocols at the data link layer to transport data between different sites.