Guest

Open Shortest Path First (OSPF)

Introduction

Open Shortest Path First (OSPF) is a routing protocol developed for Internet Protocol (IP) networks by the interior gateway protocol (IGP) working group of the Internet Engineering Task Force (IETF).
Configure

Configuration Examples and TechNotes

(All IP Routing Configuration Examples and TechNotes)

ASA Release 9.2.1 OSPF Enhancements Configuration Example

ASA/PIX with OSPF Configuration Example

Adjust Administrative Distance for Route Selection in Cisco IOS Routers Configuration Example

Configuring OSPF Authentication on a Virtual Link

Configuring a GRE Tunnel over IPsec with OSPF

Configuring a Gateway of Last Resort Using IP Commands

External LSA with Overlapping Subnets in OSPF

Guide to OSPF Application on the CSS 11000

Host and Subnet Quantities

How OSPF Injects a Default Route into a Normal Area

How OSPF Injects a Default Route into a Not So Stubby Area

How OSPF Injects a Default Route into a Stub or Totally Stub Area

How OSPF Propagates External Routes into Multiple Areas

How to Populate Dynamic Routes Using Reverse Route Injection

Initial Configurations for OSPF Over Broadcast Media

Initial Configurations for OSPF over Frame Relay Subinterfaces

Initial Configurations for OSPF over Non-Broadcast Links

Initial Configurations for OSPF over a Point-to-Point Link

MPLS Basic Traffic Engineering Using OSPF Configuration Example

OSPF Inter-Area Routing

OSPF Not So Stubby Area Type 7 to Type 5 Link-State Advertisement Conversion

OSPF Routers Connected by a Multi-Access Network

OSPF Routers Connected by a Numbered Point-to-Point Link

OSPF Routers Connected by a Point-to-Multipoint Link

OSPF Routers Connected by an Unnumbered Serial Link

OSPF Routing Loop/Sub-Optimal Routing between Cisco IOS and NXOS for External Routes Configuration Example

OSPF Virtual Link

OSPFv3 Virtual Link Configuration Example

Redistribute Connected Networks into OSPF with Subnet Keyword

Redistribute OSPFv3 Routes in BGP Configuration Example

Redistributing Between Classful and Classless Protocols: EIGRP or OSPF into RIP or IGRP

Redistributing Routing Protocols

Route-Maps for IP Routing Protocol Redistribution Configuration

Sample Configuration for Authentication in OSPF

Sample Configuration for OSPFv3

Understanding Policy Routing

Troubleshoot and Alerts

Troubleshooting TechNotes

(All IP Routing Troubleshooting TechNotes)

Common Routing Problem with OSPF Forwarding Address

Configuring a Gateway of Last Resort Using IP Commands

Down-bit Ignore Feature in OSPFV2 PE-CE Scenario on Cisco NX-OS

External LSA with Overlapping Subnets in OSPF

Host and Subnet Quantities

How Does Load Balancing Work?

How Does OSPF Generate Default Routes?

IP Addressing and Subnetting for New Users

Initial Configurations for OSPF over Non-Broadcast Links

OSPF Demand Circuit Feature

OSPF Neighbor Problems Explained

OSPF Neighbor States

OSPF Not-So-Stubby Area (NSSA)

OSPF and EIGRP Neighbor Loss, RIP and IGRP Update Loss after Upgrading to Cisco IOS 11.2 or Later

OSPF show Commands Respond Slowly

OSPF, MTU and LSA Packing Tech Note

Problems with Running OSPF in NBMA and Broadcast Mode over Frame Relay

Redistributing Between Classful and Classless Protocols: EIGRP or OSPF into RIP or IGRP

Redistributing Connected Networks into OSPF

Redistributing Routing Protocols

Route Selection in Cisco Routers

Route-Maps for IP Routing Protocol Redistribution Configuration

Scalable ISDN Backup Strategy for Large OSPF Networks

Specifying a Next Hop IP Address for Static Routes

Suboptimal Routing When Redistributing Between OSPF Processes

The "%TUN-5-RECURDOWN" Error Message and Flapping EIGRP/OSPF/BGP Neighbors Over a GRE Tunnel

The Effects of the Forwarding Address on Type 5 LSA Path Selection

Troubleshooting Duplicate Router IDs with OSPF

Troubleshooting OSPF

Understanding Policy Routing

Using the Extended ping and Extended traceroute Commands

What Are OSPF Areas and Virtual Links?

What Do %OSPF-4-ERRRCV Error Messages Mean?

What Does the show ip ospf interface Command Reveal?

What Does the show ip ospf neighbor Command Reveal?

What Is Administrative Distance?

When Are ICMP Redirects Sent?

Why Are OSPF Neighbors Stuck in Exstart/Exchange State?

Why Are Some OSPF Routes in the Database but Not in the Routing Table?

Why Does the show ip ospf neighbor Command Reveal Neighbors Stuck in Two-Way State?

Why Does the show ip ospf neighbor Command Reveal Neighbors in the Init State?

Why Doesn't OSPF Form Adjacency on a PRI, BRI, or Dialer Interface?

Why OSPF Demand Circuit Keeps Bringing Up the Link