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Building Scalable Cisco Internetworks (BSCI) Version 2.0

Instructor Name

Advanced IP Addressing

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Route Summarization and Classless Interdomain Routing

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Objectives

Upon completing this lesson, you will be able to: • Describe route summarization implementation

• Calculate route summarization

• Explain classless interdomain routing (CIDR) implementation

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What Is Route Summarization?

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Summarizing Within an Octet

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Summarizing Addresses in a VLSM-Designed Network

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Classless Interdomain Routing

• CIDR is a mechanism developed to alleviate exhaustion of addresses and reduce routing table size.

• Block addresses can be summarized into single entries without regard to the classful boundary of the network number.

• Summarized blocks are installed in routing tables.

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What Is CIDR?

• Addresses are the same as in the route summarization figure, except that Class B network 172 has been replaced by Class C network 192.

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CIDR Example

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Summary

This lesson presented these key points: • The role 4 route summarization in an internetwork

• The differences and similarities between route summarization and CIDR

• How to calculate route summarization

Written Exercise

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