© 2007 cisco systems, inc. all rights reserved.cisco public 1 planning the addressing structure...

© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 1

Planning the Addressing Structure

Working at a Small-to-Medium Business or ISP – Chapter 4

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Objectives Describe how IP Addressing is implemented in the

LAN

Subnet a given network to allow for efficient use of IP address space

Explain how Network Address Translation (NAT) and Port Address Translation (PAT) are used in a network

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Running out of Space?

As we learned in the first course IP addresses are in short supply due to an initial design that just did not anticipate the number of Internet users we have today.

Subnetting, the dividing of a network into smaller networks, provides us with a short-term solution to the long-term problem of not enough IP addresses.

How serious is the problem of not enough addresses?

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Running out of Space?

China, for example, has fewer addresses than Stanford University. Why?

When addresses were first being distributed, Stanford (one of the original universities) kept large numbers for themselves.

What will be the long-term solution?

IPv6 - an addressing scheme with 128 bits versus the current 32-bit addresses we have today. Asia may be the first continent to adopt IPv6 on a large scale. Asia has the most severe shortage, a growing population, and no way to get additional IPv4 addresses.

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And Now for Something Completely Different!

Convert these numbers to Decimal1. 000110112. 101010103. 011011114. 110000005. 010101016. 001000007. 11101101

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IP Addressing Structure Practice converting 8-bit binary to decimal

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IP Addressing Structure Convert decimal to 8-bit binary

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IP Addressing Structure Practice converting decimal to 8-bit binary

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Section 4.1 Implementation of IP Addressing in the LAN Review the purpose of an IP address

Review IP address hierarchical structure

Review the classes of IP addresses

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IP Addressing Structure Describe the dotted decimal structure of a binary IP

address and label its parts

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IP Addressing Structure Describe the general role of 8-bit binary in network

addressing and convert 8-bit binary to decimal

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Classify and Define IPv4 Addresses Name the three types of addresses in the network and

describe the purpose of each type

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Classify and Define IPv4 Addresses Determine the network, broadcast and host addresses

for a given address and prefix combination

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Classify and Define IPv4 Addresses Determine the network, broadcast and host addresses

for a given address and prefix combination

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Classify and Define IPv4 Addresses Name the three types of communication in the Network

Layer and describe the characteristics of each type

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Classify and Define IPv4 Addresses Define public address and private address

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Classify and Define IPv4 Addresses Name the three types of communication in the Network

Layer and describe the characteristics of each type

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Classify and Define IPv4 Addresses Identify the historic method for assigning addresses and

the issues associated with the method

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Determine the network portion of the host address and the role of the subnet mask Describe how the subnet mask is used to create and

specify the network and host portions of an IP address

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Determine the network portion of the host address and the role of the subnet mask Use the subnet mask and ANDing process to extract

the network address from the IP address

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Determine the network portion of the host address and the role of the subnet mask Use ANDing logic to determine an outcome

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Determine the network portion of the host address and the role of the subnet mask Observe the steps in the ANDing of an IPv4 host

address and subnet mask

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Calculating Addresses Use the subnet mask to divide a network into smaller

networks and describe the implications of dividing networks for network planners

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Calculating Addresses Use the subnet mask to divide a network into smaller

networks and describe the implications of dividing networks for network planners

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A Subnetting Example

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Implementation of IP Addressing in the LAN Describe classful subnetting including how subnet

masks are used in calculations for addressing and routing, and IP address notation for subnet masks

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Implementation of IP Addressing in the LAN Identify the number of subnet bits required for a given

network implementation

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Classless Subnetting CIDR

VLSM

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Creating Custom Subnet Masks Communicating between subnets

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Calculating Addresses Extract network addresses from host addresses using

the subnet mask

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Assigning Addresses Assigning Addresses can help separate functions

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Calculating Addresses Calculate the number of hosts in a network range given

an address and subnet mask

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Using Network Address Translation in a Network Describe the purpose and function of network address

translation (NAT) and how it is implemented

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Using Network Address Translation in a Network Define the terms used to describe how packets are

transported across a NAT configuration

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Using Network Address Translation in a Network Compare static and dynamic IP NAT and describe

when each should be used

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Using Network Address Translation in a Network Describe the purpose and function of Port-based

Address Translation (PAT) within a NAT configuration

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Using Network Address Translation in a Network Identify possible issues within a network due to NAT

configuration implementation

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Implementation of IP Addressing in the LAN Describe the origin, purpose, and function of IPv6

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Assigning Addresses Identify several changes made to the IP protocol in

IPv6 and describe the motivation for migrating from IPv4 to IPv6

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Summary

IP addressing can be tailored to the needs of the network design through the use of custom subnet masks.

Classless subnetting gives classful IP addressing schemes more flexibility through the use of variable length subnet masks.

Network Address Translation (NAT) is a way to shield private addresses from outside users.

Port Address Translation (PAT) translates multiple local addresses to a single global IP address, maximizing the use of both private and public IP addresses.

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