Network Addressing

1. Network Addressing Networking for Home and Small Businesses – Chapter 5

2. Purpose of an IP Address • A logical network address that identifies a host • A host (end-user) must have a NIC card • workstations • servers • printers • router interface • Each packet will contain a source and destination IP address Packet Tracer Activity 5.1.1 – Section 2

3. IP addresses • 32 binary digits • 4 octets • Dotted decimal notation • IP Version 4 • most common form of IP addresses • Over 4 billion possible IP addresses

4. Binary Numbers • The IP address is made up of binary numbers (1 or 0) • Humans must be able to talk computer language to send data • We do this by converting our numbering system (Base 10 to binary) • Let’s try some . . . • Convert 140 to binary • Convert 10 to binary • Convert 11010111 to Base 10 • Convert 11111110 to Base 10 • Time to play a game -- Online Activity 5.1.2 – Section 3

5. Parts of an IP Address • Hierarchial • made up of 2 parts • network • host • determined by IP class • Similar to your phone number • Area code = network • phone number = host

6. Purpose of the Subnet Mask • Helps identify network bits (all 1s) and host bits • Boolean math or “ANDING” • What happens if both source and destination IP are on the same network??

7. Types of IP Addresses • Class A • Range 1-127 • N.H.H.H • First bit in octet will be a 0 • Default subnet mask • 255.0.0.0 • can create over 16 million host addresses • 224 – 2 = 16,777,214 to be exact • why do you subtract 2??? • Used in large organizations

8. Types of IP Addresses • Class B • Range 128-191 • N.N.H.H • First bit in octet will be a 1 • Default subnet mask • 255.255.0.0 • can create over 65,000 host addresses • 216 – 2 = 65,534 to be exact • Used in medium-sized organizations

9. Types of IP Addresses • Class C • Range 192 -223 • N.N.N.H • First two bits in octet will be a 11 • Default subnet mask • 255.255.255.0 • can create 254 hosts • 28 – 2 = 254 to be exact • Used in small organizations

10. Types of IP Addresses • Class D • Range 224 - 239 • used for multicasting • not for commercial use • Class E • Range 240 - 255 • reserved for experimental use • not for commercial use

11. Private IP Addresses • Helps avoid the problem of limited IP addresses • Allows hosts to communicate locally without each device needing a public IP address • Not routed on the Internet; blocked by the ISP router • Private address ranges assigned by RFC 1918 • Request for comment • all classes can be used for any size network • most use Class A

12. Unicast Address • Most common type of address • Intended for a specific host • Must have both destination IP and MAC in the header

13. Broadcast Address • All ones in the host portion of the IP address • Class C address: 204.33.4.0 (N.N.N.H) • Broadcast address: 204.33.4.255 • MAC address all Fs • FF-FF-FF-FF-FF-FF

14. Multicast Address • Send packet to a group of devices • Must use multicast address range • Range 224.0.0.0 – 239.255.255.255 • Used for remote gaming • MAC address begins with: • 01-00-5E

15. Using Static IP Addressing • Manually configured by the network administrator • Advantages • useful for printers, servers, etc • increased control of resources (security) • Disadvantages • time consuming

16. Using Dynamic IP Addressing • Automatic assignment of IP addresses • Useful if frequent change in users (wireless hotspot) • Uses DHCP (Dynamic Host Configuration Protocol) server • IP addresses leased for a period of time • if host is removed from the network (turned off), the IP address goes back into the pool of IP address • Preferred method for large networks • reduces the burden of network support

17. Configuring DHCP • If host is configured as DHCP client, it will not have a • IP address • Subnet Mask • Default Gateway • Clients send a DHCP address • Broadcast IP and MAC • only DHCP server replies • Server responds with DHCP offer of an IP address • Host/client sends DHCP request asking server to use the IP address • Server responds with DHCP acknowledgment

18. Obtaining an IP address from DHCP server • Multifunction device (Linksys Router) provides services to clients (SOHO network) • Configuring the DHCP server • Enter router default IP address and subnet mask for internal interface • IP = 192.168.1.1 • Subnet Mask = 255.255.255.0 • On DHCP screen • check range • number of users • lease time (24 hours by default)

19. Purpose of a Gateway • Used by the router to provide the path through which hosts on one network can communicate with hosts on a different network • Default gateway address • IP address of the router interface • If DHCP is being used • the DHCP server will automatically send the correct IP interface to the host to use as the default gateway

20. Address Assignment • ISR (Integrated Services Router) • Default IP address • Class C Private Address • Configured on router interface • Internal hosts must be assigned addresses within the same network

21. Address Management • Direct Connection • direct connection from PC to ISP through modem • public address assigned to the host • Connection through Integrated Router • more than one host needs access to the Internet • modem connected to ISR • Connection through Gateway Device • ISR and modem in one unit • connect directly to ISP

22. Using NAT with a Home or Small Business Network • NAT (Network Address Translation) • Translates private IP addresses into unique public address for Internet communication • Only packets destined for different network use NAT