Chapter 6 IPv4 Addresses – Part 1 CIS 81 Networking Fundamentals Rick Graziani Cabrillo College Spring 2010

2 This Presentation For a copy of this presentation and access to my web site for other CCNA, CCNP, and Wireless resources please me for a username and password.   Web Site:

3 Note This presentation is not in the order of the book or online curriculum. This presentation also contains information beyond the curriculum.

Number Systems CIS 81 and CST 311 Rick Graziani Cabrillo College

5 Network Math

6 Base 10 (Decimal) Number System Digits (10): 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 Number of: ,000’s 1,000’s 100’s 10’s 1’s 1,

7 1. All digits start with 0 2. A Base-n number system has n number of digits:  Decimal: Base-10 has 10 digits  Binary: Base-2 has 2 digits  Hexadecimal: Base-16 has 16 digits 3. The first column is always the number of 1’s Each of the following columns is n times the previous column (n = Base-n)  Base 10: 10,000 1,  Base 2:  Base 16: 65,536 4, Number System Rules

8 Digits (2): 0, 1 Number of: 2 7 ___ ___ ___ ’s 8’s 4’s 2’s 1’s Dec

9 Digits (2): 0, 1 Number of: ’s 64’s 32’s 16’s 8’s 4’s 2’s 1’s Dec

10 Digits (2): 0, 1 Number of: ’s 64’s 32’s 16’s 8’s 4’s 2’s 1’s Dec

11 Digits (2): 0, 1 Number of: ’s 64’s 32’s 16’s 8’s 4’s 2’s 1’s Dec

12 Rick’s Program

13 Rick’s Program

14 Rick’s Program

15 Binary to/from Decimal Chapter 6 (Book and Curriculum) provides several methods and examples for doing the conversion between binary and decimal.

IPv4 Addresses

17 IPv4 Addresses IPv4 addresses are 32 bit addresses

18 IPv4 Addresses IPv4 Addresses are 32 bit addresses: We use dotted notation (or dotted decimal notation) to represent the value of each byte (octet) of the IP address in decimal

19 IPv4 Addresses An IP address has two parts:  network number  host number Which bits refer to the network number? Which bits refer to the host number?

20 IPv4 Addresses Answer: Newer technology - Classless IP Addressing  The subnet mask determines the network portion and the host portion.  Value of first octet does NOT matter (older classful IP addressing)  Hosts and Classless Inter-Domain Routing (CIDR).  Classless IP Addressing is what is used within the Internet and in most internal networks. Older technology - Classful IP Addressing (later)  Value of first octet determines the network portion and the host portion.  Used with classful routing protocols like RIPv1.  The Cisco IP Routing Table is structured in a classful manner (CIS 82)

21 Types of Addresses 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 Addresses have all 0’s in the host portion. Subnet Mask:

22 Types of Addresses 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 Broadcast Addresses have all 1’s in the host portion. Subnet Mask:

23 Types of Addresses 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 Host Addresses can not have all 0’s or all 1’s in the host portion. Subnet Mask:

24 Dividing the Network and Host Portions Subnet Mask  Used to define the:  Network portion  Host portion  32 bits  Contiguous set of 1’s followed by a contiguous set of 0’s  1’s: Network portion  0’s: Host portion

25 Dividing the Network and Host Portions Expressed as:  Dotted decimal  Ex:  Slash notation or prefix length  /16 (the number of one bits) Dotted decimal: Slash notation: /16

26 Network Addresses Network address - The address by which we refer to the network  All binary 0’s in the host portion of the address (more later) Subnet Mask:

27 Example 1 Network Address: Subnet Mask: Network Host Network Address in binary: network host Subnet Mask in binary: Prefix Length: /24

28 Example 2 Network Address: Subnet Mask: Network Host Network Address in binary: network host Subnet Mask in binary: Prefix Length : /8

29 Example 3 Network Address: Subnet Mask: Network Host Network Address in binary: network host Subnet Mask in binary: Prefix Length: /16

30 Subnet Masks – Your Turn! Underline the network portion of each address: Network Address Subnet Mask / / /16 What is the other portion of the address?

31 Subnet Masks – Your Turn! Underline the network portion of each address: Network Address Subnet Mask / / /16 What is the other portion of the address?  Host portion for host addresses

32 Why the mask matters: Number of hosts! NetworkHost Network Host Network Host 1st octet2nd octet3rd octet4th octet Subnet Mask: or / or / or /24 The more host bits in the subnet mask means the more hosts in the network. Subnet masks do not have to end on “natural octet boundaries”

33 Subnet: (/8) NetworkHost 8 bits With 24 bits available for hosts, there a 2 24 possible addresses. That’s 16,777,216 nodes! Only large organizations such as the military, government agencies, universities, and large corporations have networks with these many addresses. Example: A certain cable modem ISP has and a DSL ISP has

34 Subnet: (/16) Network Host 8 bits With 16 bits available for hosts, there a 2 16 possible addresses. That’s 65,536 nodes! 65,534 host addresses, one for network address and one for broadcast address.

35 Subnet: (/24) Network Host 8 bits With 8 bits available for hosts, there a 2 8 possible addresses. That’s 256 nodes! 254 host addresses, one for network address and one for broadcast address.

36 IP Addresses There is a tradeoff between: The number of network bits and the number of networks (subnets) you can have… AND The number of HOST bits and the number of hosts for each network you can have. This will be examined more closely, later.

37 Broadcast Addresses Broadcast address - A special address used to send data to all hosts in the network  All binary 1’s in the host portion of the address (more later)

38 Subnet Masks – Your Turn! What is the broadcast address of each network: Network Address Subnet MaskBroadcast Address / / /16

39 Subnet Masks – Your Turn! What is the broadcast address of each network: Network Address Subnet MaskBroadcast Address / / /

40 Bringing it all together Subnet Mask divides Network portion and Host portion:  1’s: Network portion  0’s: Host portion Network address:  All 0’s in the host portion of the address Broadcast address:  All 1’s in the host portion of the address

41 Bringing it all together Convert these addresses and masks to Binary (to be used later) Network: Mask: Broadcast Address Network: Mask: Broadcast Address

42 Bringing it all together Convert these addresses and masks to Binary (to be used later) Network: Mask: Bcst: Network: Mask: Bcst: Network: Mask: Bcst:

43 Bringing it all together Convert these addresses and masks to Binary (to be used later) Network: Mask: / Bcast: Network: Mask: / Bst: Network Mask: / Bcast

44 Host IP Addresses Host IP Addresses contain:  Network portion of the address  Unique combination of 0’s and 1’s in the host portion of the address  Cannot be all 0’s (network address)  Cannot be all 1’s (broadcast address) Hosts have subnet masks to determine network portion (later) /24

45 Range of hosts – Your Turn! Host addresses are all addresses between the network address and the broadcast address. What is the range of host addresses for each network? Network Address Subnet MaskBroadcast Address / / /

46 Range of hosts – Your Turn! Network Address Subnet MaskBroadcast Address through through through through through

47 Range of hosts – Your Turn! Network Address Subnet MaskBroadcast Address / through / through / through

48 Range of hosts – Your Turn! Host Addresses in binary (net) (SM) (broadcast) (net) (SM) (broadcast)

49 Range of hosts – Your Turn! Host Addresses in binary (net) (SM) (broadcast) (net) (SM) (broadcast)

50 Range of hosts – Your Turn! Host Addresses in binary (net) (SM) (broadcast)

51 Range of hosts – The rest… Host Addresses in binary (net) /24(SM) (broadcast) (net) /16 (SM) (broadcast)

52 Range of hosts – The rest… Host Addresses in binary (net) /16 (SM) (broadcast)

53 Subnet Masks: Non-Natural Boundaries Subnet masks do not have to end on natural octet boundaries Convert these to binary: Network Address Subnet Mask

54 Subnet Masks: Non-Natural Boundaries Subnet masks do not have to end on natural octet boundaries What is the range of host addresses in dotted-decimal and binary? What is the broadcast address? How many host addresses?

55 Subnet Masks: Non-Natural Boundaries Subnet masks do not have to end on natural octet boundaries … …

56 Subnet Masks: Non-Natural Boundaries Subnet masks do not have to end on natural octet boundaries … (broadcast) Number of hosts: 2 12 – 2 = 4,096 – 2 = 4,094 hosts

57 Subnet Masks: Non-Natural Boundaries Subnet masks do not have to end on natural octet boundaries … (broadcast)

58 Subnet Masks: Non-Natural Boundaries Subnet masks do not have to end on natural octet boundaries … (broadcast) Number of hosts: 2 5 – 2 = 32 – 2 = 30 hosts

Chapter 6 IPv4 Addresses – Part 1 CIS 81 Networking Fundamentals Rick Graziani Cabrillo College