html5-img
1 / 50

Chabot College

Chabot College. ELEC 99.05 IP Addressing. Logical Address Composition. Though the exact length and format of a logical (layer 3) address differs depending on the protocol, all logical addresses share this basic formula:. NETWORK NUMBER. HOST NUMBER. IP Addresses.

galya
Télécharger la présentation

Chabot College

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chabot College ELEC 99.05 IP Addressing

  2. Logical Address Composition Though the exact length and format of a logical (layer 3) address differs depending on the protocol, all logical addresses share this basic formula: NETWORK NUMBER HOST NUMBER

  3. IP Addresses • IP addresses are the most common logical addresses. (Everyone on the Internet has one.) • 32 - bit numbers (IP version 4)

  4. 32 bits not enough • 32 - bits yields 232 unique numbers • 232 =4,294,967,296 • there are over 4 billion possible IPv4 addresses • but many are “wasted” due to the allocation scheme

  5. IPv6: The Next Generation The newest version of IP (version 6, or IPng) uses 128 bits, yielding 2128 unique combinations That’s over 340,000,000,000,000,000,000,000,000,000,000,000,000 possible addresses!

  6. IPv4 vs. IPv6 • IPv6 is slowly be integrated in the existing Internet. • IPv4’s 32 bits continues to be the dominant form of IP addressing.

  7. IP Addresses We use dotted notation to represent the value of each byte (octet) of the IPv4 address in decimal. 10101100 00011100 1110110 00001010 172 . 28 . 118 . 10

  8. Dotted Decimal Notation Which addresses are legal? 201.165.321.1 12.1.2.2 198.261.34.2 645.250.2.4 209.254.130.4

  9. Dotted Decimal Notation The highest decimal number for any octet is 255, or 11111111 in binary. 201.165.321.1 12.1.2.2 198.261.34.2 645.250.2.4 209.254.130.4

  10. IP Address Classes • IPv4 uses a “class” system. • There are 5 classes of IP addresses: • Class A • Class B • Class C • Class D • Class E

  11. Address Classes Class A Used for Internet hosts Class B Used for Internet hosts Class C Used for Internet hosts Class D Used for Internet multicasts Class E Unused (used “experimentally”) Computers on the Internet can only be addressed using Class A, Class B, or Class C addresses.

  12. Determining Address Class Class A First octet is between 0 - 127 Class B First octet is between 128 - 191 Class C First octet is between 192 - 223 Class D First octet is between 224 - 239 Class E First octet is between 240 - 255 What is special about these numbers?

  13. What class is 180.129.41.9? Class A First octet is between 0 - 127 Class B First octet is between 128 - 191 Class C First octet is between 192 - 223 Class D First octet is between 224 - 239 Class E First octet is between 240 - 255 Class B

  14. What class is 224.0.0.9? Class A First octet is between 0 - 127 Class B First octet is between 128 - 191 Class C First octet is between 192 - 223 Class D First octet is between 224 - 239 Class E First octet is between 240 - 255 Class D

  15. What class is 207.21.54.25? Class A First octet is between 0 - 127 Class B First octet is between 128 - 191 Class C First octet is between 192 - 223 Class D First octet is between 224 - 239 Class E First octet is between 240 - 255 Class C

  16. Class-what’s the difference? • The address class can be used to determine: • network number • host address NETWORK NUMBER HOST NUMBER

  17. Address Classes 1st octet 2nd octet 3rd octet 4th octet Class A Network Host Host Host Class B Network Network Host Host Class C Network Network Network Host

  18. Address Classes Class A 85 45 31 158 Class B 168 65 114 201 Class C 210 144 235 56 Network Host

  19. Which part is network? 199.46.36.5 199.46.36.5 111.211.11.1 111.211.11.1 7.141.30.89 7.141.30.89

  20. Which part is network? 222.8.56.107 222.8.56.107 192.168.16.2 192.168.16.2 163.100.5.1 163.100.5.1

  21. Network Numbers • A network number is the address of the network itself. • It is not the address of any host on the network. • Network numbers are reserved and cannot be assigned to any host.

  22. Network Numbers by Class Following are examples of network numbers. Notice that the entire host portion is 0. 1st octet 2nd octet 3rd octet 4th octet Class A 63 0 0 0 Class B 142 56 0 0 Class C 209 126 155 0 Network numbers are reserved, and cannot beassigned to any workstation.

  23. Network Numbers How do you write a network number? Set the entire host portion to all zeros. 84.124.51.1 (host address) 84.0.0.0 (network number) 170.98.34.2 (host address) 170.98.0.0 (network number)

  24. Broadcast Address • Packets sent to a broadcast address will be sent to all hosts on the network. • A broadcast address is not the address of any host on the network. • Broadcast addresses are reserved and cannot be assigned to any host.

  25. Broadcast Addresses by Class Following are examples of broadcast addresses. Notice that the entire host portion is 255. 1st octet 2nd octet 3rd octet 4th octet Class A 63 255 255 255 Class B 142 56 255 255 Class C 209 126 155 255 Broadcast addresses are reserved, and cannot beassigned to any workstation.

  26. Broadcast Addresses How do you write a broadcast address? Set the entire host portion to all ones. 84.124.51.1 (host address) 84.255.255.255 (broadcast address) 170.98.34.2 (host address) 170.98.255.255 (broadcast address)

  27. The Network Number • Because the network number provides logical order, it can not be randomly assigned. • One organization administrates IP addressing.

  28. InterNIC • The management of IP addresses has been the responsibility of an organization known as InterNIC. • Currently, Network Solutions (Verisign) controls InterNIC.

  29. Network Host Host Host 8 bits 8 bits 8 bits Class A addresses First octet is between 0 - 127 Number between 0 - 127 With 24 bits available for hosts, there are 224 possible addresses. That’s 16,777,216 nodes!

  30. Class A addresses • There are 126 class A addresses. • 0 and 127 have special meaning and are not used. • Only large organizations such as the military, government agencies, universities, and large corporations have class A addresses. • Cable Modem ISPs have 24.0.0.0 • Pacbell DSL users have 63.0.0.0

  31. Class A addresses • Class A addresses account for 2,147,483,648 of the possible IPv4 addresses. • That’s 50 % of the total unicast address space!

  32. 8 bits 8 bits Class B addresses First octet is between 128 - 191 Network Network Host Host Number between 128 - 191 With 16 bits available for hosts, there are 216 possible addresses. That’s 65,536 nodes!

  33. Class B addresses • There are 16,384 (214) class B networks. • Class B addresses represent 25% of the total IPv4 unicast address space. • Class B addresses are assigned to large organizations including corporations (such as Cisco, government agencies, and school districts).

  34. 8 bits Class C addresses First octet is between 192 - 223 Network Network Network Host Number between 192 - 223 With 8 bits available for hosts, there are 28 possible addresses. That’s 256 nodes!

  35. Class C addresses • There are 2,097,152 possible class C networks. • Class C addresses represent 12.5% of the total IPv4 unicast address space.

  36. IP address shortage • In the early days of the Internet, IP addresses were allocated to organizations based on request rather than actual need.

  37. No Medium Size • 16 million • 65,536 • 256 For most organizations, 256 is too small a limit on hosts, yet 65,536 is far too many.

  38. The Subnet Mask • The solution to the IP address shortage was thought to be the subnet mask. • Formalized in 1985, the subnet mask breaks a single class A, B or C network in to smaller pieces.

  39. 8 bits 8 bits Class B Subnet Example Network Network Network Network Host Host 172 28 69 137 Address Mask 255 255 0 0 What if 216, or 65,536, hosts is too many (it is)? This network could be broken up in to smaller pieces by creating subnets.

  40. 8 bits 8 bits Class B Subnet Example Network Network Network Network Subnet Host 172 28 69 137 Address Mask 255 255 255 0 Note that the subnet mask in the third octet is set to all “1”s. Those 8 “1”s mean that all 8 of those bits are used to determine subnetwork number.

  41. Class B Subnet Example Given the Class B address 172.28.0.0 172.28.1.2 172.28.2.2 172.28.3.2 Class B Network Network Host Host Routers “see” this network as 172.28.0.0 All of these addresses are on the same network

  42. Network Network Subnet Host Class B Subnet Example Using subnets... 172.28.1.2 172.28.2.2 172.28.3.2 Internet routers still “see” this net as 172.28.0.0 But internal routers think all these addresses are on different networks, called subnetworks

  43. Network Network Subnet Host Class B Subnet Example Using the 3rd octet, 172.28.0.0 was divided into: 172.28.1.0 172.28.2.0 172.28.3.0 172.28.4.0 172.28.5.0 172.28.6.0 172.28.7.0 172.28.8.0 172.28.9.0 172.28.10.0 172.28.11.0 172.28.12.0 172.28.13.0 172.28.14.0 172.28.15.0 172.28.16.0 172.28.17.0 172.28.18.0 172.28.19.0 and so on ...

  44. 8 bits 8 bits Class B Subnet Example What’s happened to the host fields? Network Network Subnet Host 8 bits are now used to represent subnets. Only 8 bits remain for possible hosts.

  45. 8 bits 8 bits Class B Subnet Example What’s happened to the host fields? Network Network Subnet Host 8-bit subnet field = 28 subnets = 256 subnets. 8-bit host field = 28 hosts = 256 hosts. Remember, we started with 65,536 hosts!

  46. Class B Subnet Example • Run winipcfg to examine your curriculum PC’s IP address configuration. • What is your IP address class? • B The first octet is 172 Class B ranges from 128 - 191.

  47. Class B Subnet Example • The default subnet mask for a class B network is 255.255.0.0 • What subnet mask is assigned to your PC? Network Network Host Host 255 255 0 0

  48. 255 Network 255 Network Subnet 255 0 Host Class B Subnet Example • The default subnet mask for a class B network is 255.255.0.0 • What subnet mask is assigned to your PC? Network Network Host Host 255 255 0 0

  49. Class B Subnet Example • 172.28.0.0 has been divided into 256 subnets, each with 256 hosts: • 172.28.1.0 • 172.28.2.0 • 172.28.3.0 • 172.28.4.0 • 172.28.5.0 • and so on... (Actually, 256 minus 2. We’ll see why shortly...)

  50. Chabot Network 172.28.0.0 Class B Subnetted 255.255.255.0

More Related