CHAPTER 4 Topologies and Transmission Media

1. CHAPTER 4 Topologies andTransmission Media

2. Chapter 4 Networking for Manufacturing 4-2 4.1 Topology Overview LAN/MAN technology - topology - transmission medium - medium access control technique topology - the way in which the end points or stations of the network are interconnected - layout of communication links and switching elements - determines the data path that may be used

3. Chapter 4 Networking for Manufacturing 4-3 common topologies for LAN and MAN - bus/tree - ring - star

4. Chapter 4 Networking for Manufacturing 4-4 Bus and Tree Topologies bus - a linear stretch of transmission medium - no switch, no repeater - stations directly attached to the bus via taps two problems frame - destination address + data tree

5. Chapter 4 Networking for Manufacturing 4-5 Ring Topology repeaters joined by point-to-point links in a closed loop repeater link data transmission - sending station removes the packet need for access control

6. Chapter 4 Networking for Manufacturing 4-6 Star Topology a common central switch to which all stations are attached - called star coupler two ways to operate - broadcast node - switching node

7. Chapter 4 Networking for Manufacturing 4-7 Choice of Topology selection factors - reliability - expandability - performance bus/tree: most flexible with wide range of - number of devices - data rates - data types

8. Chapter 4 Networking for Manufacturing 4-8 ring: best throughput - with use of optical fiber - reliability: vulnerable for a break star - easy layout - short distance - high data rate with a small number of devices

9. Chapter 4 Networking for Manufacturing 4-9 Choice of Transmission Medium influencing factors - capacity - reliability - data type - environment

10. Chapter 4 Networking for Manufacturing 4-10 Relationship between Medium & Topology Broadband coax not for ring bidirectional propagation of baseband bus, not for tree bus/tree < ring in data rate

11. Chapter 4 Networking for Manufacturing 4-11 4.2 Bus/tree Topology multipoint configuration - collision - signal balancing medium access control (MAC) - central polling - distributed approaches segmentation by amplifiers and repeaters - n x (n-1) permutations

12. Chapter 4 Networking for Manufacturing 4-12 Baseband Coaxial Cable Baseband - digital signaling - bidirectional propagation

13. Chapter 4 Networking for Manufacturing 4-13

14. Chapter 4 Networking for Manufacturing 4-14 trade-off - data rate - cable length - number of taps repeaters to extend network - different from ring�s repeaters - transparent to network stations

15. Chapter 4 Networking for Manufacturing 4-15 Broadband Coaxial Cable analog signaling unidirectional propagation split configuration with two frequencies dual configuration with two cables

16. Chapter 4 Networking for Manufacturing 4-16 Headend for split configuration - remodulator - frequency translator pros and cons of split configuration - less cable required - less use of taps - suitable for larger systems - limited capacity - expensive headend components carrierband

17. Chapter 4 Networking for Manufacturing 4-17 Optical Fiber Bus active taps and passive taps - expensive and causing delay with active taps - signal power loss resulting in limited devices

18. Chapter 4 Networking for Manufacturing 4-18 optical bus configurations - loop bus - dual bus

19. Chapter 4 Networking for Manufacturing 4-19 4.3 Ring Topology Description repeaters connected by unidirectional links repeater transmitting whatever received data insertion, reception, and removal data removal by the transmitting repeater - automatic acknowledgement - multicast and broadcast

20. Chapter 4 Networking for Manufacturing 4-20 repeater states - listen - transmit - bypass

21. Chapter 4 Networking for Manufacturing 4-21 Ring Benefits and Problems point-to-point communication links - greater distance than baseband bus - optical fiber directly applicable - simpler electronics and maintenance than multipoint simpler resolution for duplicate address - an altered bit of the received message as an ack by the first station - the second station immediately recognizes the problem

22. Chapter 4 Networking for Manufacturing 4-22 Potential Ring Problems cable vulnerability repeater failure perambulation: pocket full of keys installation headaches size limitations timing jitter

23. Chapter 4 Networking for Manufacturing 4-23 Star-Ring Architecture wiring concentrator - easy to isolate faults - easy addition of repeaters

24. Chapter 4 Networking for Manufacturing 4-24 4.4 STAR TOPOLOGY Twisted-Pair and Optical Fiber Star LANs prewired with twisted pair - no installation cost - every office with telephone wire hub acting as a repeater

25. Chapter 4 Networking for Manufacturing 4-25 StarLAN - started with 1 Mbps - now for 10 & 100 Mbps, even 1 Gbps

26. Chapter 4 Networking for Manufacturing 4-26 Hubs and Switches bus, hub, and switching hub - Fig. 4.14 on p. 110 - bus and hub with only one transmitting station at a time - multiple transmitting stations for switching hub or LAN switch switching hub - transmission only to the station addressed in the message - no change for s/w & h/w in attached devices - dedicated capacity for each station - easy expansion types of LAN switches - store-and-forward switch - cut-through switch

27. Chapter 4 Networking for Manufacturing 4-27 Optical Fiber Star passive-star coupler - biconic fused coupler - mixing rod coupler

28. Chapter 4 Networking for Manufacturing 4-28 optical power loss - connector - cable - coupler

29. Chapter 4 Networking for Manufacturing 4-29 4.5 STRUCTURED CABLING SYSTEMS wiring standard for commercial buildings - EIA/TIA 568 - ISO 11801