Computer Networking · Advanced level

Advanced level · Module 1: Routing and Switching in Depth · Lesson 4 of 4

WAN Links and Internet Resilience

Connect sites and keep the internet available.

In this lesson you will

  • Compare WAN and internet link options
  • Design failover

Key concepts

fibre, microwave, 4G/5G, satelliteSLAsdual WANfailover testing

The lesson

Sites connect over fibre, microwave, 4G/5G or satellite; each differs in cost, speed, latency and reliability. In remote areas, satellite or 4G/5G may be the only option.

Check service level agreements for availability and repair times.

Dual-WAN routers or two ISPs with failover keep critical sites online; test failover regularly.

Step by step

  1. Compare link options for three sites.
  2. Review sample SLAs.
  3. Design failover.
  4. Plan a failover test.

Practice activity

Design WAN and internet links for the case organisation.

Expected result: A justified link design with failover.

Check your understanding

  1. Why check an SLA?

    Show answer

    It defines availability and repair commitments.

  2. What keeps a site online if one ISP fails?

    Show answer

    A second connection with failover.

Taught live by an instructor — online or in person. Free course lessons are for self-study and do not lead to a certificate — see registration options.