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Using IP Addressing in the Network Design

Designing and Supporting Computer Networks – Chapter 6

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Objectives Describe the use of a hierarchical routing and

addressing scheme

Create the IP address and naming scheme to support growth and efficient routing protocol operation

Describe IPv6 implementations and IPv6 to IPv4 interactions

Implement IPv6 on a Cisco device

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Describe the Use of a Hierarchical Routing and Addressing Scheme

Functions of a hierarchical addressing scheme:

Prevent duplication of addresses

Control access, monitor security and performance

Support modular design and scalability

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Describe the Use of a Hierarchical Routing and Addressing Scheme

Poorly-planned IP addressing can result in discontiguous subnets

Routing protocols may display more than one summary route to discontiguous subnets

Manual configuration of routing protocols may be required

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Describe the Use of a Hierarchical Routing and Addressing Scheme

VLSM provides more efficient use of IP address space

VLSM enables routers to summarize routes on classless boundaries

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Describe the Use of a Hierarchical Routing and Addressing Scheme

CIDR ignores classful boundaries

CIDR enables supernets: VLSMs with shorter prefix lengths than the defaults

• Summarization produces leaner routing tables

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Create the IP Address and Naming Scheme

Plan the entire addressing scheme in advance

Allow for significant growth

Support the physical layout, routing, and security

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Create the IP Address and Naming Scheme

Define the addressing blocks scheme to support summarization

Document locations, VLAN or network type, and number of hosts and networks

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Create the IP Address and Naming Scheme

Select the appropriate routing protocol to use in the network

Support classless routing and VLSM

Small and infrequent updates to reduce traffic

Fast convergence

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Factors in designing the routing strategy: Load balancing Authentication

Create the IP Address and Naming Scheme

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Create the IP Address and Naming Scheme

Determine when and how to summarize address space for efficient routing

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Create the IP Address and Naming Scheme

Design an address scheme for an internetwork and assign ranges for hosts, network devices, and the router interface

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Create the IP Address and Naming Scheme

Determine an appropriate naming scheme Use codes and avoid names that easily identify

protected resources Maintain consistency Document the names

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Describe IPv6 Implementations and IPv6 to IPv4 Interactions

Enhancements available with IPv6:

Mobility and security

Simpler header

Address formatting

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Describe IPv6 Implementations and IPv6 to IPv4 Interactions

Common transition methods from IPv4 to IPv6:

Dual stack

Tunneling

Proxying and translation

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Describe IPv6 Implementations and IPv6 to IPv4 Interactions

How to configure IPv6 on a Cisco device: Activate IPv6 forwarding Configure interfaces Configure name resolution

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RIPng for IPv6:

The tag parameter in interface configuration mode

The ipv6 rip name enable command on directly-connected routers

Describe IPv6 Implementations and IPv6 to IPv4 Interactions

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Summary Allocation of IP addresses must be planned and

documented. A properly-designed hierarchical IP addressing scheme

makes it easier to perform route summarization. A complex hierarchy of variable-sized networks can be

summarized at various points using a prefix address. The choice of routing protocol must support the VLSM

and summarization strategy. A good network naming scheme makes the network

easier to manage and easier to navigate. IPv6 addresses are written as a series of eight 16-bit

hexadecimal digits separated by colons.

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