1. IP ADDRESS An IP (Internet Protocol) address is a unique identifier for a node or host connection on an IP network. An IP address is a 32 bit binary number usually represented as 4 decimal values, each representing 8 bits, in the range 0 to 255 (known as octets) separated by decimal points. This is known as "dotted decimal" notation. Example: 140.179.220.200

2. It is sometimes useful to view the values in their binary form. 140. 179. 220. 200 10001100. 10110011. 11011100. 11001000

3. The network address uniquely identifies each network. every machine on the same network shares that network address as part of its IP address. In the IP address 130.57.30.56, for example, the 130.57. is the network address. The node address is assigned to, and uniquely identifies, each machine on a network. the part of the address must be unique because it identifies a particular machine—an individual, as opposed to a network, which is a group. This number can also be referred to as a host address. In the sample IP address 130.57.30.56, the.30.56 is the node address.

4. ADDRESS CLASSES The designers of the Internet decided to create classes of networks based on network size. For the small number of networks possessing a very large number of nodes, they created the rank Class A network. At the other extreme is the Class C network, reserved for the numerous networks with a small number of nodes. The class distinction for networks in between very large and very small is predictably called a Class B network. How one would subdivide an IP address into a network and host address is determined by the class designation of one's network.

5. 5 IP Address Classes

6. ClassRangeRemarks A1.0.0.0 to 126.0.0.0 127.0.0.1(loopback address) B128.0.0.0 to 191.255.0.0 C192.0.1.0 to 223.255.255.0 D224.0.0.0 to 239.255.255.255(Multi-Casting) E240.0.0.0 to 247.255.255.255(Reserved for future use)

7. In order to specify the network address for a given IP address, the node section is set to all "0"s. In our example, 140.179.0.0 specifies the network address for 140.179.220.200. When the node section is set to all "1"s, it specifies a broadcast that is sent to all hosts on the network. 140.179.255.255 specifies the example broadcast address. Note that this is true regardless of the length of the node section.

8. Class D Addresses  A Class D address begins with binary 1110 in the first octet.  First octet range 224 to 239.  Class D address can be used to represent a group of hosts called a host group, or multicast group. Class E Addresses  First octet of an IP address begins with 1111  First octet range 240 to 255.  Class E addresses are reserved for experimental purposes and should not be used for addressing hosts or multicast groups.

9. Subnetting To create sub-networks within a given IP address range Changes interpretation of IP Address slightly – Extend the network portion of IP address into the Host Part Dividing Local Part is flexible The 32 bit Subnet mask decides how many bits used for Physical Network ID and how many for host ID.

10. Subnet Masking Applying a subnet mask to an IP address allows you to identify the network and node parts of the address. The network bits are represented by the 1s in the mask, and the node bits are represented by the 0s. Performing a bitwise logical AND operation between the IP address and the subnet mask results in the Network Address or Number. For example, using our test IP address and the default Class B subnet mask, we get: Class B IP Address 10001100.10110011.11110000.11001000 140.179.240.200 11111111.11111111.00000000.00000000 255.255.000.000 -------------------------------------------------- -------------------- 10001100.10110011.00000000.00000000 140.179.000.000 Network Address = 140.179.000.000

11. Default subnet masks: Class A – 255.0.0.0 11111111.00000000.00000000.00000000 Class B – 255.255.0.0 11111111.11111111.00000000.00000000 Class C – 255.255.255.0 11111111.11111111.11111111.00000000

12. Private Networks The governing bodies that administer the Internet Protocol have identified certain networks as reserved for internal use. In general, intranets that use these networks can reduce the difficulty in administering their IP configuration and Internet access. These three networks, along with their default masks, are listed below. Network addressDefault mask 10.0.0.0255.0.0.0 172.16.0.0255.240.0.0 192.168.0.0255.255.0.0

13. CIDR Short for Classless Inter-Domain Routing, an IP addressing scheme that replaces the older system based on classes A, B, and C. With CIDR, a single IP address can be used to designate many unique IP addresses. A CIDR IP address looks like a normal IP address except that it ends with a slash followed by a number, called the IP network prefix.

14. For example: 172.200.0.0/16 The IP network prefix specifies how many addresses are covered by the CIDR address, with lower numbers covering more addresses. An IP network prefix of /12, for example, can be used to address 1,048,576 former Class C addresses. CIDR addresses reduce the size of routing tables and make more IP addresses available within organizations. CIDR is also called super netting.

15. Under CIDR, the subnet mask notation is reduced to a simplified shorthand. Instead of spelling out the bits of the subnet mask, it is simply listed as the number of 1s bits that start the mask. In the above example, instead of writing the address and subnet mask as 192.60.128.0, Subnet Mask 255.255.252.0 the network address would be written simply as: 192.60.128.0/22 which indicates starting address of the network, and number of 1s bits (22) in the network portion of the address. If you look at the subnet mask in binary (11111111.11111111.11111100.00000000), you can easily see how this notation works.

16. The use of a CIDR notated address is the same as for a Classful address. Classful addresses can easily be written in CIDR notation Class A = /8, Class B = /16, Class C = /24

17. 17 TCP/IP Protocol Suite

18. Introduction to TCP/IP The U.S. DoD created the TCP/IP reference model because it wanted a network that could survive any conditions. TCP/IP model has become the Internet standard.

19. 19 Application Layer Handles high-level protocols, issues of representation, encoding, and dialog control.

20. 20 Transport Layer Five basic services: Segmenting upper-layer application data Establishing end-to-end operations Sending segments from one end host to another end host Ensuring data reliability Providing flow control

21. Internet Layer Best path determination and packet switching

22. 22 TCP Header

23. 23 UDP Header

24. World Wide Web What constitutes World Wide Web? Web Browsers Web Content Web Site URL – Uniform Resource Locator HTTP – Hyper Text Transfer Protocol HTML – Hyper Text Markup Language

25. HTTP GET, POST and HEAD Methods GET method GET method – Parameters are encoded and passed along with the URL – URL encoding: TBD – In web usually, parameters are passed as name-value pairs Example: http://abcbooks.co.in/cgi-in/getinfo.exe?title=Web+Servershttp://abcbooks.co.in/cgi-in/getinfo.exe? POST method – The parameters from the browser are passed as part of the Message body – Typically the CGI program receives the message body through STDIN and decodes it – HTTP response for POST is usually a program output HEAD method – Gets just the header information from the server – Usually used to get only information about the content – Helps save on bandwidth