© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1 Version 4.0 Addressing the Network – IPv4 Network Fundamentals – Chapter 6

2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addressing  Method for assigning addresses

3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addressing  Class A The class A address block was designed to support extremely large networks with more than 16 million host addresses. Limited to 128 networks, they could only be allocated to approximately 120 companies or organizations.  Class B designed to support the needs of moderate- to large-size networks with more than 65,000 hosts  Class C provide addresses for small networks with a maximum of 254 hosts. Used a /24 prefix.

4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  The importance of using a structured process to assign IP addresses to hosts. Preventing duplication of addresses Each host in an internetwork must have a unique address Providing and controlling access Some hosts, such as servers, provide resources to the internal network as well as to the external network Monitoring security and performance identify the device on the network that has a problematic address.

5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  End user devices can obtain addresses either statically through an administrator or dynamically through DHCP  Static With a static assignment, the network administrator must manually configure the network information for a host. At a minimum, this includes entering the host IP address, subnet mask, and default gateway.  Dynamic DHCP enables the automatic assignment of addressing information such as IP address, subnet mask, default gateway, and other configuration information. The configuration of the DHCP server requires that a block of addresses, called an address pool, be defined to be assigned to the DHCP clients on a network.

6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses

7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  Internet Assigned Numbers Authority (IANA)  IANA ( is the master holder of the IP addresses. The IP multicast addresses and the IPv6 addresses are obtained directly from IANA  IANA allocated IPv4 address space to various other registries to manage for particular purposes or for regional areas. These registration companies are called Regional Internet Registries (RIR).  The following are the major registries:

8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv6  IPv6 creating expanded addressing capabilities was the initial motivation for developing this new protocol. Other issues were also considered during the development of IPv6, such as these: Improved packet handling Increased scalability and longevity Quality of service (QoS) mechanisms Integrated security  To provide these features, IPv6 offers the following:  128-bit hierarchical addressing to expand addressing capabilities  Header format simplification to improve packet handling  Improved support for extensions and options for increased scalability/longevity and improved packet handling  Flow-labeling capabilities as QoS mechanisms  Authentication and privacy capabilities to integrate security

9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  IPv6

10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Subnet mask  Subnetting allows creating multiple logical networks from a single address block.

11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Subnet mask

12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Subnet mask

13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Subnet mask

14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Ping command can be used to determine if the IP protocol is operational on a local host

15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Ping can be used to verify that a local host can communicate with a gateway across a local area network

16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Ping can be used to verify that a local host can communicate via a gateway to a device in remote network

17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Ping can be used to verify that a local host can communicate via a gateway to a device in remote network

18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Tracert/traceroute can be used to observe the path between two devices as they communicate and trace the steps of tracert/traceroute's operation

19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Tracert/traceroute can be used to observe the path between two devices as they communicate and trace the steps of tracert/traceroute's operation

20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Summary

21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public