1. © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1 Version 4.0 Addressing the Network – IPv4 Network Fundamentals – Chapter 6 Sandra Coleman, CCNA, CCAI

2. 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.

3. 3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Describe an octet, network portion, host portion

4. 4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Describe these parts of an IPv4 address. Total of 32 bits long!

5. 5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Practice converting 8-bit binary to decimal – See online curriculum section 6.1.3 for an online practice tool.

6. 6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Convert decimal to 8-bit binary

7. 7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  Practice converting decimal to 8-bit binary – Online curriculum 6.1.5 for online practice tool

8. 8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Name the three types of addresses in the network and describe the purpose of each type

9. 9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Types of addresses  Network The network address is a standard way to refer to a network. For example, we could refer to the network shown in the figure as "the 10.0.0.0 network.“ All hosts in the 10.0.0.0 network will have the same network bits (high-order bits). The lowest address is reserved for the network address. This address has a 0 for each host bit in the host portion of the address. This is the part routers use to forward packets!  Broadcast Special address for each network that allows communication to all the hosts in that network. To send data to all hosts in a network, a host can send a single packet that is addressed to the broadcast address of the network. The broadcast address uses the highest address in the network range. This is the address in which the bits in the host portion are all 1s.  Host Every end device requires a unique address to deliver a packet to that host. In IPv4 addresses, we assign the values between the network address and the broadcast address to the devices in that network.

10. 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 – practice this…online curriculum section 6.2.2

11. 11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Types of networks  Unicast - the process of sending a packet from one host to an individual host. This is used for all normal traffic.  Broadcast - the process of sending a packet from one host to all hosts in the network. 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. 2 types of broadcast – ROUTERS DO NOT FORWARD BROADCASTS! Limited - is used for communication that is limited to the hosts on the local network. Directed - directed broadcast is sent to all hosts on a specific network.  Multicast - the process of sending a packet from one host to a selected group of hosts. Some examples include: Video and audio distribution, Routing information exchange by routing protocols, Distribution of software, News feeds

12. 12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Name the three types of communication in the Network Layer and describe the characteristics of each type

13. 13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  Identify the address ranges reserved for these special purposes in the IPv4 protocol

14. 14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Private addressing  Must be unique in the LAN in which they are located  CAN NOT be routed on the internet. If hosts with a private address need access to the internet, must use some form of NAT or PAT (discussed in a later course) to translate the address to a public address  The private address blocks are: (KNOW THESE!) Class A - 10.0.0.0 to 10.255.255.255 (10.0.0.0 /8) Class B - 172.16.0.0 to 172.31.255.255 (172.16.0.0 /12) Class C - 192.168.0.0 to 192.168.255.255 (192.168.0.0 /16)

15. 15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Public addressing  The remaining addresses (not in the private address block range) are designed to access the internet and carry the user wherever he/she wants to go.  Some of these addresses are designated for special purposes.

16. 16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Special IP Addresses – can’t be assigned!  None of these addresses will be forwarded by a router and most can’t be assigned to a device (Link-local & Test-Net are the exception to that rule) 1.Network Address – FIRST address of any network 2.Broadcast Address – LAST address of any network 3.Default Route – 0.0.0.0 – 0.255.255.255 – ‘catch-all’ route when a specific route is NOT available 4.Loopback Addresses – 127.0.0.1 – 127.255.255.255 – used to test the configuration of TCP/IP on the local host (your NIC) – bypasses some of the lower layers of TCP/IP stack 5.Link-Local Addresses - 169.254.0.0 to 169.254.255.255 These addresses can be automatically assigned to the local host by the OS in environments where no IP configuration is available. I.E. can’t get DHCP configurations. 6.Test-Net Addresses - 192.0.2.0 to 192.0.2.255 - is set aside for teaching and learning purposes

17. 17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses  See online curriculum 6.2.5 for an online tool

18. 18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses

19. 19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classify and Define IPv4 Addresses

20. 20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Classful Addressing  Class A – designed to support extremely large networks with more than 16 million host addresses.  Class B – designed to support the needs of moderate to large size networks with more than 65,000 hosts  Class C – the most commonly available of the historic address classes. This address space was intended to provide addresses for small networks with a maximum of 254 hosts.  Class D – Multicasting  Class E – Experimental

21. 21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Limits of Classful routing  Abandoned in the 1990’s  Assumptions were made about the subnet mask based on the first octet. This is true of the OS and the routing protocols  Wasted address space If a company needed 260 addresses, they would have to be assigned a class B address of 65,000 addresses.

22. 22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Planning an addressing scheme..WHY?  Preventing duplication of addresses – keep up with IP addresses as they are assigned. Duplication is NOT allowed!  Providing and controlling access - if a server has a random address assigned (DHCP), blocking access to its address is difficult and clients may not be able to locate this resource. Some devices need not only internal, but external access (servers, for example)  Monitoring security and performance - examine network traffic looking for addresses that are generating or receiving excessive packets. If we have proper planning and documentation of the network addressing, we can identify the device on the network that has a problematic address.

23. 23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning addresses  Some examples of different types of hosts are: End devices for users Servers and peripherals (static addresses, please) Hosts that are accessible from the Internet Intermediary devices (static addresses please)  Each of these different device types should be allocated to a logical block of addresses within the address range of the network.

24. 24 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Address planning..  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?  If there are more devices than available public addresses (found a LOT with class C (254 hosts) assignments, only those devices that will directly access the Internet - such as web servers - require a public address. A NAT service would allow those devices with private addresses to effectively share the remaining public addresses.

25. 25 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses

26. 26 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Static addressing  The network administrator must manually configure the network information for a host. At a minimum, this includes entering the host IP address, subnet mask, and default gateway.  Static addresses have some advantages over dynamic addresses. For instance, they are useful for printers, servers, and other networking devices that need to be accessible to clients on the network.  When using static IP addressing, it is necessary to maintain an accurate list of the IP address assigned to each device. These are permanent addresses and are not normally reused. Typically assigned to servers, network printers, routers, switches, etc, but NOT to PC’s (laptop or desktop)

27. 27 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  Explain how end user devices can obtain addresses dynamically through DHCP.

28. 28 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  Explain which types of addresses should be assigned to devices other than end user devices

29. 29 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Public Addresses  IANA – Internet Assigned Numbers Authority  IANA gave these out directly until about mid-1990’s.  All remaining IPv4 were then assigned to RIR’s (Regional Internet Registries) to maintain and then to start with IPv6 addresses  ARIN is who your ISP gets its IP address blocks from.  ARIN (American Registry for Internet Numbers) - North America Region http://www.arin.nethttp://www.arin.net

30. 30 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Assigning Addresses  Identify different types of ISPs and their roles in providing Internet connectivity

31. 31 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ISP’s  The farther you get from the internet backbone, services are Cheaper Less reliable Slower

32. 32 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv6 features  Larger address space  Data types and class of service updated  Uses authentication and encryption  Why was it developed? To give us expanded addressing capabilities!

33. 33 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv6  128 bit addressing in hexadecimal #’s separated by colons  Simpler header to speed up Tx/Rx speed  Authentication and Privacy capabilities  Designed for scalability (ability to grow)

34. 34 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IPv6 continued…  IPv6 is not merely a new Layer 3 protocol - it is a new protocol suite.  New protocols at various layers of the stack have been developed to support this new protocol.  There is a new messaging protocol (ICMPv6) and new routing protocols.

35. 35 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Determine the network portion of the host address and the role of the subnet mask Network Portion – blue SN Mask bits ALL 1’s Host Portion – red SN Mask bits ALL 0’s CIDR Notation(Classless Inter Domain Routing – Prefix /24)

36. 36 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public  ANDing is like multiplying…convert IP and subnet mask down to binary, multiply them together..get a binary result…convert back to decimal.  This is what routers DO!!!

37. 37 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public  Use ANDing logic to determine an outcome

38. 38 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public  Observe the steps in the ANDing of an IPv4 host address and subnet mask..online curriculum 6.4.3

39. 39 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses  Use the subnet mask to divide a network into smaller networks

40. 40 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Powers of 2

41. 41 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating a Subnet  We will subnet the IP address: 223.14.17.0  What class IP address is this? Class C

42. 42 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step #1  Determine the default subnet mask  Class C default subnet mask: 255.255.255.0

43. 43 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step #2  Determine the number of subnets needed and hosts needed on each to determine how many bits to borrow from the host ID.  Need: 13 subnets 10 hosts on each subnet

44. 44 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step #3  Figure the actual number of subnets and hosts by borrowing bits from host ID.  Let’s see how many subnets and hosts we will have by borrowing 4 bits from the host.  2 bb = possible subnets  2 br = possible hosts  2 br – 2 = usable hosts

45. 45 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step #3 continued… 223.14.17.0 X X H H 2 bb =16 possible subnets 2 br =16 possible hosts for each subnet

46. 46 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step #3 continued…  We get 16 possible subnets and 16 possible hosts for each subnet because: For the 4 bits borrowed each bit can be a 1 or a 0 leaving you with 2 4 or 16 possible combinations. The same goes for the 4 leftover host bits.  Important: There are only 14 available hosts on each subnet. Why?  Because you cannot use the first and last address within each subnet. (No exceptions!)  For each, one is the broadcast address and one is the network address.

47. 47 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step #4  Determine the subnet mask. 223.14.17.0 X X H H Where X represents the borrowed bits for subnetting.

48. 48 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step #4 continued…  Add the place values of X together to get the last octet decimal value of the subnet mask. 128 + 64 + 32 + 16 = 240 The subnet mask is: 255.255.255.240 The subnet mask is used to reveal the subnet and host address fields in IP addresses.

49. 49 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step 5  Determine the ranges of host addresses for each subnet.

50. 50 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step 5 continued… Subnet #Subnet BitsHost BitsIn Decimal 100000000-1111.0 -.15 200010000-1111.16 -.31 300100000-1111.32 -.47 400110000-1111.48 -.63 501000000-1111.64 -.79 601010000-1111.80 -.95 701100000-1111.96 -.111 801110000-1111.112 -.127

51. 51 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step 5 continued… Subnet #Subnet BitsHost BitsIn Decimal 910000000-1111.128 -.143 1010010000-1111.144 -.159 1110100000-1111.160 -.175 1210110000-1111.176 -.191 1311000000-1111.192 -.207 1411010000-1111.208 -.223 1511100000-1111.224 -.239 1611110000-1111.240 -.255

52. 52 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public VLSM…not wasting IP addresses..  Extract network addresses from host addresses using the subnet mask. MUST know how to do this!  Always start with the largest block and work down!

53. 53 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public VLSM– Know THIS!  Calculate the number of hosts in a network range given an address and subnet mask

54. 54 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public  Given a subnet address and subnet mask, calculate the network address, host addresses and broadcast address (6.5.4) MUST DO THIS!

55. 55 © 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 (6.5.5)

56. 56 © 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 (6.5.6)

57. 57 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Which one of the following are valid HOST addresses?  192.168.12.127/26  172.31.5.155/26  172.31.5.193/26  192.168.6.95/27  192.168.5.159/27  192.168.5.207/27  Be able to do this on your test!

58. 58 © 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 (127.0.0.1). If this fails, TCP/IP is not properly installed on the host!

59. 59 © 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

60. 60 © 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 Remember, many network administrators limit or prohibit the entry of ICMP datagrams into the corporate network. Therefore, the lack of a ping response could be due to security restrictions and not because of non-operational elements of the networks.

61. 61 © 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

62. 62 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Testing the Network Layer  ICMP – provides control and error messages to the TCP/IP protocol suite.

63. 63 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ICMP messages  If the TTL mechanism expires before a packet reaches its destination, what happens? The router DROPS the packet Sends an ICMP ‘Time Exceeded’ message back to the source!

64. 64 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1.You MUST learn how to do this. 2.It will be part of your hands-on finals 3.NO CALCULATORS ALLOWED on this test or the CCNA! 4.Practice….Practice…… Practice….That’s the only way to get this to stick with you. 5.Test – TBD 6.Online Test - TBD 7.Study Guide: 1.Pg. 152 – ALL of it 2.Pg. 155 – Binary Matching exercise 3.Pg. 156 – Concept Questions 4.Pg. 157-158 – Concept Questions 8.Activities – 6-1, 6-2 – pg. 178, pg. 183 9.We have several handouts, I’ve posted some of them on the WEB so that if you lose yours, you can print yourself another one. WOW…are you okay? Still with me?