Functions 1

 How long is MAC address?  How is mac address used in data communication?  What is a frame?  What does an IP address look like? 2

3 TCP IP Virtual End-to-end Connection

4  Network layer is responsible for moving data through a set of networks.  Router (R) helps to forward data through different networks  IP protocol operates at Network Layer R R - Router RR R R R

5  Large networks are divided into many small networks  Networks identified by their network addresses ◦ Example: , subnet mask:

6  Network address helps to identify path (route) through network from start to destination.  Each network has an address, a number that is common to all PCs on the network  1.0 as 1 is the common number between 1.1, 1.2, 1.3 ◦ Each PC within the network has an address (blue ring), e.g., 1.3  What is the network address for Eagle Server? Router Figure 2

7  Also called Layer 3 or Protocol address or logical address ◦ Configurable - can be changed by changing TCP/IP settings ◦ Needs to change when device is moved to a network having different network address

8 Hierarchy in IP addressing IP addresses are hierarchical They have a defined structure Conceptually each IP address is a pair divided into a prefix and a suffix –Prefix, also called (net-id) identifies network to which computers are attached. –Suffix, aka, (host-id) identifies hosts within that network.

9 IP Addresses are 32 bits. Divide into four 8 bit sections (octets). Convert from binary to decimal.

10  Five different classes of IP addresses ◦ A, B, C, D, E  Class A, B and C are primary classes  Used for assigning IP addresses  Class D, E used for special purposes ◦ Class D for multicast addresses  E.g., Videoconferencing ◦ Class E addresses are reserved for experimentation

11 Network ID Host ID Network IDHost ID 8 16 Class A 32 Class B 10 Class C 110 Multicast Addresses Class D 1110 Reserved for experiments Class E  How to associate an address with a class  Look at the first group of numbers in the dotted decimal notation  ClassRange  A0-127  B  C  D  E Which Class has the largest Host ID and how many bits long?

12  Subnet mask identifies the boundary between netid and hostid  Default subnet masks are ◦ Class A : ◦ Class B : ◦ Class C :  Which class has more hosts?  Which class supports more networks? Network Host Network Host Network Host 1st octet2nd octet3rd octet4th octet Class A Class B Class C

13  Logical ‘AND’ IP address and subnet mask to get Net-ID. ◦ E.g. IP address is , Find Network ID using default subnet mask of for class C  Find the binary representation of IP address and subnet mask  Logical ‘AND’ with subnet mask  IP Address  Subnet mask Network ID  Convert binary to decimal value ◦ Network ID: AND

What is the class of IP address in the figure? Router

15  Underline the network portion of each address: Network Address Subnet Mask / / /16  What is the other portion of the address?

16  Underline the network portion of each address: Network Address Subnet Mask / / /16  What is the other portion of the address?