Addressing the Network – IPv4

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Addressing the Network – IPv4

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Addressing the Network – IPv4

  1. 1. Addressing the Network – IPv4 Network Fundamentals – Chapter 6 ITE I Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 1
  2. 2. Objectives  Identify the structure IP addressing and demonstrate the ability to convert between 8-bit binary and decimal numbers.  Identify an IPv4 address, classify by type and describe how it is used in the network  Identify how addresses are assigned to networks by ISPs and within networks by administrators  Identify 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.  Identify common testing utilities to verify and test network connectivity and operational status of the IP protocol stack on a host. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 2
  3. 3. IP Addressing Dotted decimal Structure  An IP address structure in dotted decimal form can be seen by inspecting the TCP/IP properties of a PC as below: ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 3
  4. 4. IP Addressing Dotted Binary Structure  Dotted decimal IP addresses can be expressed in dotted binary form. Each octet is simply converted to its binary equivalent ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 4
  5. 5. 8 bit Binary to decimal conversion  1 Write down the 8 bit binary number  2 Write down the decimal value above each bit  3 Add only decimal values above a 1 bit (Ignore values above 0 bits)  4 The total for all 8 bits is decimal number ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 5
  6. 6. Decimal to Binary (using short division) ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 6
  7. 7. Decimal to Binary (using short division) ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 7
  8. 8. Decimal to 8- bit binary ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 8
  9. 9. Network, Broadcast and host Addresses An address can represent:  The Network only (Network Address, Wire Address)  All hosts i.e. PC’s, Servers, Printers, Router interfaces on the network (Broadcast Address) e.g DHCP request, ARP request or Routing update (RIP)  A single host on the network (Host Address) ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 9
  10. 10. Example  Determine the network, broadcast and host addresses for a given address and prefix combination ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 10
  11. 11. Example  172.16.4.32/28 (28 Network bits 4 Host bits)  Network address is 172.16.4.32  Subnet mask is 255.255.255.240  First Useable host address is 172.16.4.33  Last Useable host address is 172.16.4.46  Broadcast address is 172.16.4.47 i.e. all host bits are set to 1 ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 11
  12. 12. Calculations (Convert both numbers to Binary) ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 12
  13. 13. Calculations (Work out the range of numbers in the host portion) ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 13
  14. 14. Calculation (Add the host values to the complete address) Useable addresses = Total addresses – 2 = 24- 2 (where 4 is the number of bits in host portion) = 16 - 2 = 14 ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 14
  15. 15. Address communication types  Unicast – 1 to 1 communication  Broadcast 1 to all network host communication (Directed or Limited)  Multicast 1 to a group of hosts on the network communication ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 15
  16. 16. IPv4 Addresses usage  Address ranges reserved for special purposes in the IPv4 protocol Legacy Class A,B and C Used for hosts Multicast address used for Routing Protocols Exchange, Software distribution, Audio and Video Broadcasts ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 16
  17. 17. Public and Private addresses  Public addresses can move across the internet in packets  Private address must remain within a network ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 17
  18. 18. Classes of IPv4 Addresses  Packets with Private address (Link-Local and Test – Net) are not routed on the internet ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 18
  19. 19. Classify and Define IPv4 Addresses  In the early 1980s IPv4 addresses were divided into classes ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 19
  20. 20. Assigning Addresses  Addresses can be public or private and assigned manually, automatically by server or automatically by hosts operating systems in a peer to peer network ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 20
  21. 21. Configuring Addresses  TCP/IP setting allows to setting of IP addresses ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 21
  22. 22. Assigning Addresses  Network hardware can have IPv4 addresses also ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 22
  23. 23. IANA, Regional agencies and ISPs  Internet Assigned Number Authority (IANA), Internet regional agencies and ISPs manage the allocation of IP addresses to organisations IANA manage addresses overall and the registries manage the addresses for particular geographic regions ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 23
  24. 24. ISPs and the Internet Backbone  All ISPs are connected to the internet back. Tier1 directly, Tier 2 through Tier 1 and Tier 3 through Tier 2  The bigger the company the closer it is to the back bone ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 24
  25. 25. The subnet mask can be used to find the network for an IP address To calculate the network address of a given IP address the logic ANDing of any 2 bit values must be understood AND Truth table for two bit values ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 25
  26. 26. Logically AND each bit in the IP address with its subnet mask bit, the result is the network bit ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 26
  27. 27. Another Example ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 27
  28. 28. Subnetting a Network address  Subnetting is the process of borrowing bits from the left hand side of the host portion of the address and subnet mask and reassigning them as network bits, in order to create smaller subnets within a network address. Networks can be subnetted on the basis of subnets required or hosts per subnet ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 28
  29. 29. Subnetting use a table ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 29
  30. 30. Subnetting a Network address  Extend the subnet mask to divide a network into smaller networks ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 30
  31. 31. Subnetting Starting point To begin we have the address 192.168.1.0/24.This gives us 1 network of 28 = (256 – 2) = 254 useable hosts ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 31
  32. 32. Subnetting – decide the network needs  The network requires 2 separate networks for each router interface  We therefore borrow 1 bit from the host portion of the subnet mask changing it from /24 to /25  Borrowing 1 bit gives 21 = 2 networks ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 32
  33. 33. Subnetting- look at the host portion  The new host portion is now 7 bits wide. This give us 2 1 = 2 networks each of  27=128 – 2= 126 useable hosts  The addresses for each subnet can be determined by the decimal weighted value of the last subnet mask network bit This bit has been borrowed from the host portion and converted to a network bit ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 33
  34. 34. Subnetting – examine the octet  Each octet in an IP address and subnet mask have bits worth: 128 64 32 16 8 4 2 1 1 Octet of subnet mask) 0 0 0 0 0 0 0 (4th  In the example we can see that the decimal weighted value is 128.  This means that our subnet addresses will increase in steps of 128 hosts  This gives the 2 subnet addresses of: (Note 2 subnets because 1 bit was borrowed i.e. 21 =2 subnets 192.168.1.0/25 192.168.1.128/25 ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 34
  35. 35. Subnetting work out the host portion ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 35
  36. 36. Subnetting- calculate the addresses in each subnet  The host addresses on each subnet are calculated as before:  For 1st subnet 192.168.1.0 =(Network + all host bits are zeroes)  192.168.1.1=(Network + First useable value in host portion)  192.168.1.126 =(Network + Last useable value in host portion)  192.168.1.127 (BC) =(Network + all host bits are ones) ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 36
  37. 37. Subnetting- calculate the addresses in each subnet  For 2nd subnet 192.168.1.128 =(Network + all host bits are zeroes)  192.168.1.129=(Network + First useable value in host portion)  192.168.1.254 =(Network + Last useable value in host portion)  192.168.1.255 (BC) =(Network + all host bits are ones) ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 37
  38. 38. IPv6 protocol  Improve packet handling via simplified header, scalability via 128 bit addressing scheme, QOS via Flow labeling and integrated security ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 38
  39. 39. Summary  IP addresses are hierarchical (have structure) with a network, host and sometimes a subnet portion.  All IPv4 addresses can represent a complete network, a specific host, a group of hosts or broadcast address of the network  Addressing authorities and ISPs allocate address ranges to companies. Companies can then divide the address ranges into subnets by extending the subnet mask and reassigning host bits to network bits  Networks can be subnetted on the basis of subnets required or hosts per subnet or both  If networks are being subnetted based on hosts required. Always start with the largest host requirement  Planning makes the best use of the addressing scheme  IP network addresses can be tested by using Ping and Tracert  IPv6 is a new layer 3 protocol with new protocols at various layers to support it ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 39
  40. 40. Labs  IPv4 Address Subnetting Part 1 Network address Network broadcast address Total number of host Number of hosts  IPv4 Address Subnetting Part 2 The subnet address of a subnet The broadcast address of a subnet The range of host addresses for a subnet The maximum number of subnets for a subnet mask The number of hosts for each subnet The number of subnet bits The number of a subnet ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 40

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