© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ITE PC v4.0 Chapter 1 1 Addressing the Network – IPv4 Network Fundamentals – Chapter 6

ITE PC v4.0 Chapter 1 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.

ITE PC v4.0 Chapter 1 3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Each device on a network must be uniquely defined. At the Network layer, the packets of the communication need to be identified with the source and destination addresses of the two end systems.  With IPv4, this means that each packet has a 32-bit source address and a 32-bit destination address in the Layer 3 header.

ITE PC v4.0 Chapter 1 4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv4 Addressing Structure  Dotted Decimal Binary patterns representing IPv4 addresses are expressed as dotted decimals by separating each byte of the binary pattern, called an octet, with a dot. It is called an octet because each decimal number represents one byte or 8 bits.   is expressed in dotted decimal as: 

ITE PC v4.0 Chapter 1 5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Types of Address in IPv4  Network address - The address by which we refer to the network  Broadcast address - A special address used to send data to all hosts in the network  Host addresses - The addresses assigned to the end devices in the network  Network Prefixes An important question is: How do we know how many bits represent the network portion and how many bits represent the host portion? When we express an IPv4 network address, we add a prefix length to the network address. The prefix length is the number of bits in the address that gives us the network portion. For example, in /24, the /24 is the prefix length - it tells us that the first 24 bits are the network address. This leaves the remaining 8 bits, the last octet, as the host portion.

ITE PC v4.0 Chapter 1 6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Conti…

ITE PC v4.0 Chapter 1 7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Conversion Binary to Decimal Decimal to Binary

ITE PC v4.0 Chapter 1 8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  binary to decimal

ITE PC v4.0 Chapter 1 9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Convert decimal to 8-bit binary

ITE PC v4.0 Chapter 1 10 © 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

ITE PC v4.0 Chapter 1 11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Three types of communication in the Network  Unicast - the process of sending a packet from one host to an individual host  Broadcast - the process of sending a packet from one host to all hosts in the network  Multicast - the process of sending a packet from one host to a selected group of hosts

ITE PC v4.0 Chapter 1 12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Broadcast Transmission  When a host receives a packet with the broadcast address as the destination, it processes the packet as it would a packet to its unicast address. Broadcast transmission is used for the location of special services/devices for which the address is not known or when a host needs to provide information to all the hosts on the network. Some examples for using broadcast transmission are: Mapping upper layer addresses to lower layer addresses Requesting an address Exchanging routing information by routing protocols

ITE PC v4.0 Chapter 1 13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Multicast Transmission  Multicast transmission is designed to conserve the bandwidth of the IPv4 network. It reduces traffic by allowing a host to send a single packet to a selected set of hosts. To reach multiple destination hosts using unicast communication, a source host would need to send an individual packet addressed to each host. With multicast, the source host can send a single packet that can reach thousands of destination hosts.  Some examples of multicast transmission are: Video and audio distribution Routing information exchange by routing protocols Distribution of software News feeds  Multicast Clients Hosts that wish to receive particular multicast data are called multicast clients. The multicast clients use services initiated by a client program to subscribe to the multicast group.

ITE PC v4.0 Chapter 1 14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Different type of Addresses  Public and Private  Default Route  Loopback  Link-Local Addresses: IPv4 addresses in the address block to ( /16) are designated as link-local addresses. These addresses can be automatically assigned to the local host by the operating system in environments where no IP configuration is available.  TEST-NET Addresses: The address block to ( /24) is set aside for teaching and learning purposes.

ITE PC v4.0 Chapter 1 15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Public and Private Address

ITE PC v4.0 Chapter 1 16 © 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

ITE PC v4.0 Chapter 1 17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Legacy IPv4 Addressing  Classfull A (0-127) B( ) C( ) D( ) E( )  Classless  The system that we currently use is referred to as classless addressing. With the classless system, address blocks appropriate to the number of hosts are assigned to companies or organizations without regard to the unicast class.

ITE PC v4.0 Chapter 1 18 © 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

ITE PC v4.0 Chapter 1 19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Planning to Address the Network  Preventing Duplication of Addresses  Providing and Controlling Access  Monitoring Security and Performance  Assigning Addresses within a Network

ITE PC v4.0 Chapter 1 20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  Identify different types of ISPs and their roles in providing Internet connectivity

ITE PC v4.0 Chapter 1 21 © 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.

ITE PC v4.0 Chapter 1 22 © 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

ITE PC v4.0 Chapter 1 23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Extract network addresses from host addresses using the subnet mask

ITE PC v4.0 Chapter 1 24 © 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

ITE PC v4.0 Chapter 1 25 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Given a subnet address and subnet mask, calculate the network address, host addresses and broadcast address

ITE PC v4.0 Chapter 1 26 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Given a pool of addresses and masks, assign a host parameter with address, mask and gateway

ITE PC v4.0 Chapter 1 27 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Given a diagram of a multi-layered network, address range, number of hosts in each network and the ranges for each network, create a network scheme that assigns addressing ranges to each network

ITE PC v4.0 Chapter 1 28 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Use the ping command to determine if the IP protocol is operational on a local host

ITE PC v4.0 Chapter 1 29 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Use ping to verify that a local host can communicate with a gateway across a local area network

ITE PC v4.0 Chapter 1 30 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Use ping to verify that a local host can communicate via a gateway to a device in remote network

ITE PC v4.0 Chapter 1 31 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  Use tracert/traceroute to observe the path between two devices as they communicate and trace the steps of tracert/traceroute's operation

ITE PC v4.0 Chapter 1 32 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ICMP  ICMP is the messaging protocol for the TCP/IP suite. ICMP provides control and error messages and is used by the ping and traceroute utilities.  The types of ICMP messages - and the reasons why they are sent - are extensive. We will discuss some of the more common messages.  ICMP messages that may be sent include:  Host confirmation  Unreachable Destination or Service(0 = net unreachable, 1 = host unreachable, 2 = protocol unreachable, 3 = port unreachable )  Time exceeded  Route redirection

ITE PC v4.0 Chapter 1 33 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Conti…  Source Quench  The ICMP Source Quench message can be used to tell the source to temporarily stop sending packets. If a router does not have enough buffer space to receive incoming packets, a router will discard the packets. If the router has to do so, it may also send an ICMP Source Quench message to source hosts for every message that it discards.

ITE PC v4.0 Chapter 1 34 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Summary

ITE PC v4.0 Chapter 1 35 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public