New Training: Configure and Verify an OSPF NSSA

In this 7-video skill, CBT Nuggets trainer Keith Barker teaches you about the purpose and configuration of Not-So-Stubby Areas (NSSA) in an OSPF network. Watch this new Cisco training.

Learn Cisco with one of these courses:

• Cisco CCNP Enterprise Core

• Cisco OSPF Configuration

This training includes:

• 7 videos

• 35 minutes of training

You’ll learn these topics in this skill:

• Intro to OSPF NSSA

• LSA Review

• NSSA Overview

• Configure and Verify an OSPF NSSA

• ABR LSA Type 7 Conversions for NSSA

• Default routes and the Totally NSSA

• Review and Quiz

What is OSPF NSSA?

OSPF NSSA stands for "Open Shortest Path First, Not-So-Stubby-Area," and is a non-proprietary extension of an existing stub area. A stub area does not follow external route advertisements, reducing the size of the database needed to execute a connection. External routes are those routes which have been redistributed into OSPF from any other protocol. These make up a substantial percentage of link states in each router's database.

NSSAs are similar to stub areas, preventing the flooding of AS-external link-state advertisements (LSAs) and use default routing paths to external destinations. Because of their external focus, they must be placed at the edge of the OSPF routing domain. The primary advantage NSSAs have over traditional stub areas is that they are more flexible and can import external routes into the OSPF routing domain. This trait facilitates transit service to smaller routing domains that are not already part of the OSPF routing domain.