1. 1 A Station A begins transmission at t=0 A Station A captures channel at t=t prop CSMA Random Access Scheme

2. 2 sensing P-Persistent CSMA

3. 3 Non-Persistent CSMA 0.81 0.51 0.14 S G 0.01 0.1 1 Performance of non-persistent CSMA

4. 4 1-Persistent CSMA 0.53 0.45 0.16 S G 0.01 0.1 1 Performance of 1-persistent CSMA

5. 5 A begins to transmit at t=0 A B B begins to transmit at t= t prop -  B detects collision at t= t prop A B A B A detects collision at t= 2 t prop -  It takes 2 t prop to find out if channel has been captured Reaction time in CSMA-CD

6. 6 Probability of 1 successful transmission: framecontentionframe P success is maximized at p=1/n: n P max Packet Transmission and Contention periods

7. 7 Aloh a Slotted Aloha 1-P CSMA Non-P CSMA CSMA/CD a  max Achievable Throughputs

8. 8 a = 0.01 a = 0.1 a = 0.2 Frame Transfer delay for Ethernet

9. 9 Preamble SD Destination Address Source Address Length Information Pad FCS 7 12 or 6 24 64 to 1518 bytes Synch Start frame 0 Single address 1 Group address Destination address is either single address or group address (broadcast = 111...111) Addresses are defined on local or universal basis 2 46 possible global addresses 0 Local address 1 Global address 802.3 MAC Frame IEEE 802.3 MAC Frame

10. 10 Preamble SD Destination Address Source Address Type Information Pad FCS 7 12 or 6 24 64 to 1518 bytes Synch Start frame Ethernet Frame Ethernet frame (DIX Standard)

11. 11 AA AA 03 Information MAC Header FCS 802.3 Frame LLC PDU SNAP Header Type ORG SNAP PDU 3 2 111 SNAP frame for encapsulating Ethernet frames

12. 12 (a) (b) transceivers Ethernet Cabling

13. 13 (a) (b) High-Speed Backplane or Interconnection fabric Single collision domain Ethernet hub-and-switch topologies

14. 14 Ethernet Switch Server 100 Mbps links 10 Mbps links Fast Ethernet

15. 15 IEEE 802.3 Medium Alternatives –10 Base5 10Base2 10BaseT10BaseF Medium Thick Coax Thin Coax Twisted Pair Optical Length 500m 200m 100m 2km Topology Bus Bus Star P2P Fast Ethernet 100Base T4 100BaseT 100BaseF Medium Twisted Pair Cat.4 Twisted Pair Cat.5 Opt. Multimode UTP 4 Pairs UTP two pairs two strands Length 100m 100m 2km Topology Star Star Star

16. 16 Gigabit Ethernet 1000 BaseSX 1000BaseLX 1000BaseCX 100BaseT Medium Optical Fiber Optical Fiber Shielded Copper Twist.Pair multimode single mode cable cat.5 UTP 2 strands 2 strands Length 550m 5km 25m 100m Topology Star Star Star Star