1. Part 1 IPv4 and Subnetting

2. Announcements and Outline Assessment 1 Results: Range: 66 – 112 Average: 85 9 students did extra credit Curve 3 MC Questions (6 pts) 3pts on Essay Questions IPv4 Review of packet formats and addressing Assigning Addresses Public vs. Private Dotted decimal notation 2

3. IP Packet Formats 5 - 3 IPv4 Header: 192 bits (24 bytes) IPv6 Header: 320 bits (40 bytes)

4. IPv6 Addressing IPv4 uses 4 byte addresses:  Total of 4 billion possible addresses  IP addresses often assigned in (large) groups Giving out many numbers at a time  IPv4 address space has been used up quickly IPv6 uses 16 byte addresses:  3.2 x 10 38 addresses, 320 undecillion  Little chance this address space will ever be used up 5 - 4

5. Types of Addresses 5 - 5 Application Layer Address Network Layer Address Data Link Layer Address Network Layer Data Link Layer Application Layer Transport Layer

6. Assigning Addresses 5 - 6

7. 7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  The dotted decimal structure of a binary IP address and label its parts

8. 8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Addressing Structure  The general role of 8-bit binary in network addressing and convert 8-bit binary to decimal 6.1.1.1

9. IPv4 Addresses 4 byte (32 bit) addresses  Strings of 32 binary bits Dotted decimal notation  Used to make IP addresses easier to understand for human readers  Breaks the address into four bytes and writes the digital equivalent for each byte Example: 128.192.56.1 5 - 9 1 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 1

10. IP Addresses (dotted decimal notation) Examples 10

11. Binary and Decimal Conversion 5 - 11

12. Converting from binary to decimal 128 (2 ^7 ) 64 (2 ^6 ) 32 (2 ^5 ) 16 (2 ^4 ) 8 (2 ^3 ) 4 (2 ^2 ) 2 (2 ^1 ) 1 (2 ^0 ) 12 In decimal, this number is: Use the same template as before Add the place values corresponding to the locations that have 1 in the number E.g.: 11100011

13. Converting from binary to decimal 1286432168421 13 You should be comfortable working with binary numbers with up to 8 bits  e.g.: 10011011 This number is equal to: Largest possible number with 8 digits?

14. Converting from binary to decimal Try converting the following numbers to decimal  10000110  11001000  11110000 14 1286432168421 1286432168421

15. IPv4 – Binary to Dotted Decimal Notation 5 - 15

16. Converting from decimal to binary 1286432168421 Used to compute subnet sizes, broadcast addresses etc. – You should be comfortable with binary numbers with up to 8 digits One technique is to fill-in-the-blanks – Start with template below – Place 1 in the leftmost-possible position – Subtract place-value and repeat until subtraction yields 0

17. Converting from decimal to binary 1286432168421 17 e.g.: 133 1286432168421

18. Converting from decimal to binary Try converting the following numbers to binary  134  200  240 18

19. IP addresses – structure IP addresses are not assigned at random like MAC addresses – Or even on first-come-first-serve basis The first few address bits define the organization to which the address belongs – Remaining bits are unique to the computer (host) within the organization 19

20. Assigning Addresses - Network Classes (IPv4) 5 - 20 https://www.arin.net/knowledge/address_filters.html

21. Class A networks 21

22. Class B and C networks Class B networks Class C networks 22

23. Public and Private IP Addresses The use of these addresses need not be unique among outside networks. Hosts that do not require access to the Internet at large may make unrestricted use of private addresses. The private address blocks are: 10.0.0.0 to 10.255.255.255 (10.0.0.0 /8) 172.16.0.0 to 172.31.255.255 (172.16.0.0 /12) 192.168.0.0 to 192.168.255.255 (192.168.0.0 /16) Does UNCW use the private address blocks within their network? 5 - 23

24. 24 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Introducing NAT and PAT  NAT is designed to conserve IP addresses and enable networks to use private IP addresses on internal networks.  These private, internal addresses are translated to routable, public addresses.  IPv4 addresses are almost depleted.  NAT/PAT has allowed IPv4 to be the predominant network protocol

25. When should you use public / private addresses? 5 - 25