© 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

2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 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

3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 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?

4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 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.

5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public And Now for Something Completely Different!  Convert these numbers to Decimal

6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Practice converting 8-bit binary to decimal

7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Convert decimal to 8-bit binary

8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Practice converting decimal to 8-bit binary

9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 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

10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Describe the dotted decimal structure of a binary IP address and label its parts

11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Describe the general role of 8-bit binary in network addressing and convert 8-bit binary to decimal

12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Name the three types of addresses in the network and describe the purpose of each type

13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Determine the network, broadcast and host addresses for a given address and prefix combination

14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Determine the network, broadcast and host addresses for a given address and prefix combination

15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Name the three types of communication in the Network Layer and describe the characteristics of each type

16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Define public address and private address

17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Name the three types of communication in the Network Layer and describe the characteristics of each type

18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Identify the historic method for assigning addresses and the issues associated with the method

19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 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

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

21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Determine the network portion of the host address and the role of the subnet mask  Use ANDing logic to determine an outcome

22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 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

23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Use the subnet mask to divide a network into smaller networks and describe the implications of dividing networks for network planners

24 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Use the subnet mask to divide a network into smaller networks and describe the implications of dividing networks for network planners

25 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public A Subnetting Example

26 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 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

27 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Implementation of IP Addressing in the LAN  Identify the number of subnet bits required for a given network implementation

28 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public

29 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classless Subnetting  CIDR  VLSM

30 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Creating Custom Subnet Masks  Communicating between subnets

31 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Extract network addresses from host addresses using the subnet mask

32 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  Assigning Addresses can help separate functions

33 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Calculate the number of hosts in a network range given an address and subnet mask

34 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Using Network Address Translation in a Network  Describe the purpose and function of network address translation (NAT) and how it is implemented

35 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Using Network Address Translation in a Network  Define the terms used to describe how packets are transported across a NAT configuration

36 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Using Network Address Translation in a Network  Compare static and dynamic IP NAT and describe when each should be used

37 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Using Network Address Translation in a Network  Describe the purpose and function of Port-based Address Translation (PAT) within a NAT configuration

38 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Using Network Address Translation in a Network  Identify possible issues within a network due to NAT configuration implementation

39 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Implementation of IP Addressing in the LAN  Describe the origin, purpose, and function of IPv6

40 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  Identify several changes made to the IP protocol in IPv6 and describe the motivation for migrating from IPv4 to IPv6

41 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 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.

42 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public