Addressing the Network – IPv4

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Addressing the Network – IPv4

Network Fundamentals – Chapter 6

http://www.catc.edu.cn/

2思科网络技术学院理事会 . http://www.catc.edu.cn

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.



Course Index

6.1 IPv4 Addresses 6.2 Addresses for Different Purpose 6.3 Assigning Addresses 6.4 Is It On My Network? 6.5 Calculating Addresses 6.6 Testing the Network Layer 6.7 Lab and Activities



6.1 IPv4 Addresses



6.1.1 The Anatomy of an IPv4 Address 32bit Dotted Decimal Network and Host Portions



6.1.2 Knowing the Number – Binary to Decimal Conversion



6.1.4 Knowing the Number – Decimal to Binary Conversion



6.2 Addresses for Different Purpose



6.2.1 Types of Addresses in an IPv4 network Network address - The address by which we refer to the network. It is

the lowest address is reserved for the network address. (All host bits is 0)

Broadcast address - A special address used to send data to all hosts in the network. It is the highest address in the network range. (All host bits is 1)

Host addresses - The addresses assigned to the end devices in the network.



6.2.2 Calculating Network, Hosts and Broadcast Addresses Network Prefixes

Indicated by the Prefix LengthThe number of bits in the address that gives us the network portion.



6.2.2 Calculating Network, Hosts, and Broadcast Addresses



6.2.3 Unicast, Broadcast, Multicast – Types of Communication



Limited Local broadcast address

STOP

255.255.255.255



Directed broadcast address

192.168.20.255

192.168.20.0192.168.1.0



6.2.4 Reserved IPv4 Address Range



6.2.5 Public address and private address Public Addresses Private address

10.0.0.0 to 10.255.255.255 (10.0.0.0 /8)172.16.0.0 to 172.31.255.255 (172.16.0.0 /12)192.168.0.0 to 192.168.255.255 (192.168.0.0 /16)

NAT

Practice 6.2.5



6.2.6 Special IPv4 addresses Network and Broadcast Addresses Default Route:0.0.0.0 Loopback:127.0.0.0/8 Link-Local Addresses:169.254.0.0 /16 TEST-NET Addresses:192.0.2.0 /24



6.2.7 Legacy IPv4 addressing



6.3 Assigning Addresses



6.3.1 Planning to Addresses the Network It’s a structure process, should be planned and documented.

Preventing duplication of addressesProviding and controlling accessMonitoring security and performance

The different types of hosts within a networkhosts are associated with an IPv4 network by a common network portion of the addressEnd devices for usersServers and peripherals Hosts that are accessible from the InternetIntermediary devices



6.3.1 Planning to Addresses the Network Planning to Addresses the Network Considerations

include:Will there be more devices connected to the network than public addresses allocated by the network's ISP?Will the devices need to be accessed from outside the local network?If devices that may be assigned private addresses require access to the Internet, is the network capable of providing a Network Address Translation (NAT) service?



6.3.2 Static or Dynamic Addressing for End User Devices

Addresses for User DevicesStatic Assignment of AddressesDynamic Assignment of Addresses

DHCP



6.3.3 Assigning Addresses to Other devices Addresses for Servers and Peripherals Addresses for Hosts that are Accessible from Internet Addresses for Intermediary Devices Routers and Firewalls



6.3.4 & 6.3.5 Who Assigns the Different Addresses? The organization of address management



6.3.6 Overview of IPv6 IPv6 Features and Advantages

128-bit hierarchical addressing - to expand addressing capabilitiesHeader format simplification - to improve packet handlingImproved support for extensions and options - for increased scalability/longevity and improved packet handlingFlow labeling capability - as QoS mechanismsAuthentication and privacy capabilities - to integrate security



6.4 Is It On My Network?



6.4.1 The subnet mask - Defining the network and host portions



6.4.2 ANDing – What is in our network? When ANDing between the address and the subnet mask is performed, the

result yields the network address. Routers use ANDing to determine an acceptable route for an incoming packet. An originating host use ANDing to determine if a packet should be sent directly

to a host in the local network or be directed to the gateway.



6.4.3 The ANDing Process An Exercise of ANDing



6.5 Calculating Addresses



6.5.1 Basic Subnetting Each interface on a router must have a unique network ID Create the subnets by using (borrow) one or more of the host bits

as network bits. Subnets number=2^n (n = the number of bits borrowed) Host number= 2^n - 2 (n=the number of bits left for hosts)



6.5.1 Basic Subnetting Subnetting Example (4 networks)



6.5.1 Basic Subnetting Subnetting Example (8 networks)



6.5.2 Subnetting – Dividing Networks into Right Sizes

Step 1 Determine the Total Number of HostsThis includes end user devices, servers, intermediate devices, and router interfaces.



6.5.2 Subnetting – Dividing Networks into Right Sizes Step 2 Determine the Number and Size of the Networks

Consider the number of networks and the size of each required based on common groupings of hosts.




Step 3 Allocating Addresses




Subnetting – Spreadsheet, a helpful tool



6.5.3 Subnetting – Subnetting a Subnet Subnetting a subnet, or using Variable Length Subnet

Mask (VLSM) was designed to maximize addressing efficiency



6.5.3 Subnetting – Subnetting a Subnet VLSM Example

In the example, using a standard subnetting (/26 prefix length) scheme would be wasteful.




Using VLSM



6.5.4 Determining the Network Address



6.5.5 Determining the Number of hosts



6.5.6 Determining Valid Addresses for Hosts



6.6 Testing the Network Layer



6.6.1 Ping 127.0.0.1 – Testing the Local Stack Ping

It is a utility for testing IP connectivity between hosts. Pinging the Local Loopback (127.0.0.1)

A response from 127.0.0.1 indicates that IP is properly installed on the host.



6.6.2 Ping gateway Testing connectivity to the local LAN



6.6.3 Ping remote host Testing connectivity to remote LAN



6.6.4 Traceroute (tracert) – Tesing the Path It takes advantage of Time to Live (TTL)



6.6.5 ICMPv4 – The Protocol Supporting Testing and Messaging Internet Control Messaging Protocol (ICMPv4)

ICMP is the messaging protocol for the TCP/IP suiteICMP provides control and error messagesIt is actually a separate Layer 3 protocol of the TCP/IP suite ICMP messages that may be sent include:

Host conformationUnreachable Destination or ServiceTime exceededRoute redirectionSource quench



Summary


Addressing the Network – IPv4

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