1. Supplemental for Ch.8 IS 620 Dr. Lee http://164.76.102.55/~hueilee

2. Flags in TCP Segment A: Acknowledgement S: Synchronization F: Final

3. IP Address Classes How large is the network part in an IP address? Originally, IP had address classes with fixed numbers of bits in the network part Class A: 8 bits (24 bits in local part) Large Organization, 1-126 Class B: 16 bits (16 bits in local part) Medium organization, 128-191 Class C: 24 bits (8 bits in local part) Small Organization, 192-223

4. Class A IP Address IP address begins with 0 7 remaining bits in network part Only 128 possible Class A networks 24 bits in local part Over 16 million hosts per Class A network! All Class A network parts are assigned or reserved

5. Class B IP Address IP address begins with 10 (1st zero in 2nd position) 14 remaining bits in network part Over 16,000 possible Class B networks 16 bits in local part Over 65,000 possible hosts A good trade-off between number of networks and hosts per network Most have been assigned

6. Class C IP Address IP address begins with 110 (1st zero in 3d position) 21 more bits in network part Over 2 million possible Class C networks! 8 bits in local part Only 256 possible hosts per Class C network! Unpopular, because large firms must have several

7. Local Host 127.0.0.1