© 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 Objectives  Explain the structure IP addressing and demonstrate the ability to convert between 8-bit binary and decimal numbers.  Given an IPv4 address, classify by type and describe how it is used in the network.  Explain how addresses are assigned to networks by ISPs and within networks by administrators.  Determine the network portion of the host address and explain the role of the subnet mask in dividing networks.  Given IPv4 addressing information and design criteria, calculate the appropriate addressing components.  Use common testing utilities to verify and test network connectivity and operational status of the IP protocol stack on a host.

3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Inside the devices, digital logic is applied for interpretation of the address  Human – 32 bits is difficult to interpret + remember  Represented as dotted decimal

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

5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Converting 8-bit binary to decimal

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

7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Converting 32 bits IP Address

8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Converting 32 bits IP Address

9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Converting 32 bits IP Addresses

10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Converting 32 bits IP Address

11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Converting 32 bits IP Address  Exercise  ?

12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Decimal to 8-bit binary

13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Decimal to 8-bit binary

14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Decimal to 8-bit binary

15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Decimal to 8-bit binary

16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Converting decimal to 8-bit binary- practice

17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing Types of Communication  In IPv4 network, the hosts can communicate in one of three different ways

18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing Types of Communication  Unicast  Most common in CS and P2P

19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing Types of Communication  Broadcast  Using Broadcast Address  Two types: Directed Broadcast – Broadcast is sent to all hosts on a specific network/nonlocal Limited Broadcast - Broadcast is sent to all hosts on local network

20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing Types of Communication  Multicast  Only to selected set of hosts

21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing Types of Communication

22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addresses  Three types of addresses in the network: Network address: A special address that refers to the network Cannot be assign to a device, only reference to a network The lowest address in IPv4 address range Broadcast address: A special address used to send data to all hosts in the network The highest address in IPv4 address range Host addresses: The unicast addresses assigned to the end devices in the network

23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addresses

24 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addresses Network prefix  When an IPv4 network address is expressed, a prefix length added to the network address.  This prefix length is the number of bits in the address that gives the network portion.  Written in slash format. That is a forward slash (/) followed by the number of network bits.  Example, in /24, the /24 is the prefix length.  This tells you that the first 24 bits are the network address. The remaining 8 bits, the last octet, are the host portion.

25 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addresses Network prefix  Network not always assigned a /24 prefix  Depends on the number of hosts on the network 2 8 =256, 2 7 =128…

26 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addresses  Determine the network, broadcast and host addresses for a given address and prefix combination /24 Type of AddressLast octet in binary Last octet in decimal Full address in decimal Network Broadcast First Useable Host Address Last Useable Host Address

27 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addresses  Exercise  Determine the network, broadcast and host addresses for a given address and prefix combination /25 Type of AddressLast octet in binary Last octet in decimal Full address in decimal Network Broadcast First Useable Host Address Last Useable Host Address

28 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Public address and Private address  Although most IPv4 host addresses are public addresses designated for use in networks that are accessible on the Internet, there are blocks of addresses used in networks that require limited or no Internet access.  These addresses are called private addresses.  The private address blocks are ■ /8 ( to ) ■ /12 ( to ) ■ /16 ( to )  Private space address blocks are set aside for use in private networks.

29 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Public address and Private address  Private space address blocks are set aside for use in private networks.  Packets using these addresses as the source or destination should not appear on the public Internet  The router or firewall device at the perimeter of these private networks must block or translate these addresses  These services, called Network Address Translation (NAT), can be implemented on a device at the edge of the private network. NAT changes the private space addresses in the IPv4 packet header to a public space address

30 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Public address and Private address

31 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Purpose of several special addresses  Default route The IPv4 default route is This default route is a “catch all” route to route packets when a more specific route is not available /8 address block ( – ).  Loopback address The loopback address use to direct traffic to themselves. Shortcut method for TCP/IP applications and services that run on the same device to communicate with one another. Two services on the same host can bypass the lower layers of the TCP/IP stack address is used, address block /8 ( to ) is reserved.

32 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Purpose of several special addresses ■ Link-local address /16 address blocks ( to ) can be automatically assigned to the local host by the operating system in environments where no IP configuration is available. only suitable for communication with other devices connected to the same network  ■ Test-net addresses set aside for teaching and learning purposes. block /24 ( to ) used in documentation and network examples.

33 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public  TBC