IP Routing: Static Routes and OSPF

Read routing tables, build static, default and floating routes, run single-area OSPFv2 and keep gateways available with HSRP, on Cisco routers in Packet Tracer.

Intermediate · Networking · about 13 hours · 4 modules · certificate on completion

Taught by Chaiyapòn Srisomboòn, Kaimànà Kahananùi, AI Learning Companions.

About this course

Routers decide where every packet goes, and knowing how they decide is what lets you design networks that work and fix them when they don't. In this course you'll learn to read a Cisco routing table line by line and predict which route a router will use, by longest prefix match, administrative distance and metric. You'll configure static routes, host routes, default routes and floating backups for IPv4 and IPv6, then let routers find their own routes with single-area OSPFv2: router IDs, network statements, passive interfaces, DR and BDR elections on shared LANs, and costs that steer traffic where you want it. Finally you'll troubleshoot OSPF neighbours that won't come up, and keep a LAN's default gateway available with HSRP.

Every configuration is shown step by step in Cisco Packet Tracer with the output you should see, and every module ends with a lab your instructor reviews against real show command output, including one where you break and fix OSPF on purpose. The course ends with a project in which you build the routed network for a three-site company, with OSPF, a default route to the internet, path control and HSRP. It follows the IP Connectivity topics in Cisco's published CCNA (200-301) exam topics.

What you'll learn

  • Read every part of a Cisco routing table and predict the route a router will use, by longest prefix match, administrative distance and metric
  • Configure and verify IPv4 and IPv6 static routes: network, host, default and floating static
  • Configure single-area OSPFv2 with router IDs, passive interfaces, costs and DR/BDR priorities
  • Verify OSPF neighbours and routes, and troubleshoot adjacencies that won't form
  • Explain how first-hop redundancy keeps a default gateway available, and configure HSRP

Skills you'll gain

IP routing, Routing tables, Static routing, Default and floating static routes, IPv6 static routing, OSPFv2, OSPF troubleshooting, HSRP, Cisco IOS, Cisco Packet Tracer

Tools

Cisco Packet Tracer, Cisco IOS

Before you start

IPv4 subnetting and basic Cisco IOS configuration (command modes, interfaces and show commands); IP Addressing and Subnetting and LAN Switching cover them. You need Cisco Packet Tracer (free with a Cisco Networking Academy account).

Aligned with: Cisco CCNA (200-301) exam topics: IP Connectivity

Modules

  1. How routers choose a path

    Read a Cisco routing table line by line, and learn the rules a router uses to choose one route from several: longest prefix match, administrative distance and metric.

    • Reading the routing table (12 min)
    • Longest prefix match and administrative distance (12 min)
    • Hands-on lab: Predict, then prove: forwarding decisions

  2. Static and default routes

    Configure the routes a router can't learn for itself: static routes to networks and hosts, default routes for stub networks and the internet, floating backups, and their IPv6 equivalents.

    • Configuring static routes (12 min)
    • Default and floating static routes (12 min)
    • IPv6 static routes (10 min)
    • Hands-on lab: Static, default and floating routes

  3. Single-area OSPFv2

    Let routers find their routes for themselves: how OSPF builds a map of the network, how to configure it in one area, and how it elects designated routers and chooses the cheapest paths.

    • How OSPF works (12 min)
    • Configuring single-area OSPFv2 (14 min)
    • DR and BDR, network types and OSPF cost (14 min)
    • Hands-on lab: Configure single-area OSPF

  4. Troubleshooting and first-hop redundancy

    Find out why OSPF neighbours won't come up or routes are missing, then keep hosts' default gateway available with HSRP.

    • Troubleshooting OSPF (14 min)
    • First-hop redundancy with HSRP (12 min)
    • Hands-on lab: Troubleshoot OSPF and add a virtual gateway

Project: Route a three-site company network

Build and document the routed network for a company with a head office, a branch and an internet connection. At head office, two routers, HQ1 and HQ2, share the user LAN and give it an HSRP virtual gateway, with HQ1 active. The branch router, BR1, has its own LAN and a link to each head-office router. HQ1 also links to an ISP router, which stands for the internet with a loopback address in 198.51.100.0/24. Plan the company's addresses from 10.50.0.0/16 (a /24 for each LAN and a /30 for each link) and use 203.0.113.0/30 for the ISP link. Run single-area OSPFv2 (area 0) on BR1, HQ1 and HQ2, with router IDs set, passive interfaces wherever no neighbour is needed, and auto-cost reference-bandwidth 1000 on all three. Give HQ1 a static default route to the ISP and advertise it into OSPF, and give the ISP a static route back to 10.50.0.0/16. Use OSPF cost so the branch's traffic prefers the BR1 to HQ1 link, with BR1 to HQ2 as the backup. Then prove it works and survives failures.

Part of

Cisco, CCNA, Cisco IOS and Cisco Packet Tracer are trademarks of Cisco Systems, Inc. This course is independent: Cisco hasn't made or endorsed it, and it doesn't give you a Cisco certification.

Start the course free