Networking & The Internet Data Flow

The OSI Model

Physical Please Data Do Network Not Transport Throw Session Sausage Presentation Pizza Application Away Application All Presentation People Session Seem Transport To Network Need Data Presentation Processing

IP Addresses What is an IP address? What does IP stand for? What is a MAC address? Why would you use a static IP address? What does refer to?

The OSI Model IP Addresses work at the Network Layer of the OSI model To make it easier for us humans to remember, IP addresses are normally expressed in decimal format as a "dotted decimal number“ like this:

The OSI Model IP Addresses are in fact saved in binary. So this address: Actually is read as this:

The OSI Model IP Addresses are 32 bit numbers. Why? Because they are made up of 4 x 8bit binary numbers = 32 Each digit = 1 ‘bit’ of memory This means that worldwide there are a possible 4,294,967,296 IP addresses

The OSI Model However, within IP addresses there are certain reserved numbers. The first number or ‘octet’ (eight bits) shows the type of network the IP belongs to: 001 – 126 are Class A Addresses Class A are large networks consisting of many Ips Class A IPs are stored as: Network Node Up To 16,777,214 Possible IPs

The OSI Model 128 – 191 are Class B Addresses Class B are medium networks consisting of a large number of IPs Class B IPs are stored as: Network Node Up To 65,534 Possible IPs

The OSI Model are Class C Addresses Class C are small networks consisting of several IPs Class C IPs are stored as: Network Node Up To 254 Possible IPs

The OSI Model Some IPs are ‘reserved’ Home, or Loopback: Broadcast Address:

The OSI Model Within Networks, IPs are Subnetted to allow IPs to be assigned within the network. In your Internet Browser go to: What information can you find about the network you are on?

Homework – Due in next Friday What is the Purpose of Subnetting? Discuss your findings in a short essay format (more than a page, less than five) Essay format: Intro, discussion, conclusion, SOURCES!