route summarization and classless inter -domain routing

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Building Scalable Cisco
Internetworks (BSCI) Version 2.0
Instructor Name

3. Advanced IP Addressing
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4. Route Summarization and
Classless Interdomain Routing
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5. © 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—1-5
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Class B network 172 has been replaced by Class C network 192.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

13. Written Exercise
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