Non-Ethernet Networks

1. Non-Ethernet Networks Chapter 7

2. Contents • Define the characteristics, cabling, and connectors used in Token Ring • Describe the characteristics, cabling, and connectors used in ARCnet and LocalTalk • Explain the characteristics, cabling, and connectors used in FDDI and ATM

3. Introduction • Ethernet monopolizes today’s networks with an 80-90% share • Other technologies such as those introduced in this chapter are fading • Network+ expects you to understand them

4. Token Ring

5. Token Ring • Token Ring is also called IEEE 802.5 • Supports 16 Mbps compared to 10 Mbps for 10BaseT Ethernet • 100 and 1000 Mbps Token Ring standards exist • Uses a physical star topology • Uses a logical ring topology

6. Logical Ring Topology • Token Ring nodes communicate directly only with the upstream and downstreamneighbors

7. Token Passing • A token passing system controls access to the ring • Nodes may only transmit when they receive the token • Only one node may transmit at a time • All nodes check packets for their MAC address • The destination node acknowledges receipt of the packet by sending a packet back to the sender • Then the sender releases a new free token

8. Token Passing • After receiving a token, a Token Ring node with data to send creates a new packet and sends it to its downstream neighbor • A station must wait for the token before it can send data • Access to the wire is predictable rather than random – called deterministic

9. Token Ring Packet • Token Ring packets include the source MAC address, destination MAC address, the data to be transmitted, and a Frame Check Sequence (FCS) to check for errors

10. Token Ring Speed • Token Ring runs at 4 Mbps or 16 Mbps • Newer versions run faster but Network+ does not include them • Bandwidth is used more efficiently than with Ethernet since there are no collisions • The slowest device on the ring determines the speed of the ring

11. Priorities • Some systems may be configured for a higher priority • Access to the token is more often • Rarely used

12. Physical Star Topology • A physical ring topology cannot function if the ring breaks

13. Logical Ring Topology • Token Ring uses a physical star topology and logical ring topology • The ring is hidden inside the hub, called a Multistation Access Unit (MAU or MSAU) • Nodes connect to the hub with UTP or shielded twisted pair (STP)

14. Shielded Twisted Pair • Original Token Ring networks used shielded twisted pair (STP) • Two pairs of copper wires surrounded by a metal shield to prevent electrical interference • Up to 260 computers • Distance from hub to computer may not exceed 100 meters

15. Connectors • Token Ring uses a Type 1 connector for STP • These hermaphroditic (neither male nor female) are called IBM-type Data Connectors (IDC) or Universal Data Connectors (UDC) – plug into each other • Token Ring cards use a 9-pin female connector

16. Token Ring over UTP • Token Ring over UTP uses the same UTP cable and RJ-45 connectors as Ethernet • Uses two pairs: 3-6 and 4-5 • UTP is much cheaper than STP • Supports up to 72 nodes within 45 meters of the MAU

17. Connecting MAUs • Extending a Token Ring network requires extending the ring topology • MAUs have special ports call Ring In and Ring Out to extend the ring • Ring Out connects to Ring In

18. Connecting MAUs • When linked together properly, MAUs form a single logical ring • Up to 33 MAUs may be connected

19. Token Ring More efficient use of bandwidth Guarantees every node gets some bandwidth Appears to be a dying technology Ethernet Less expensive Simpler devices Much larger installed base leading to cheaper equipment Token Ring vs. Ethernet

20. ARCnet and LocalTalk

21. ARCnet • Attached Resource Computer Network (ARCnet) was invented by Datapoint Corporation • Both a physical and logical star topology • Uses token passing • Used RG-62 coaxial cable initially and later UTP • 2.5 Mbps (ARCnet Plus ran at 20 Mbps)

22. ARCnet Hubs • 8 or 16 port ARCnet hubs may be daisy-chained or strung together to support additional nodes • Segment lengths up to 600 meters • ARCnet now supports UTP and fiber optic cabling • Popular in robotics and industrial controls but not computer networks

23. LocalTalk • Created by Apple • Bus topology • Proprietary cabling using round DIN-style connectors

24. LAN to WAN – FDDI and ATM

25. FDDI • Fiber Distributed Data Interface (FDDI) was developed by the American National Standards Institute (ANSI) • High speed, highly redundant technology designed for high-speed backbones • Uses a dual token passing ring • Each ring runs at 100 Mbps with an aggregate speed of 200 Mbps

26. FDDI Topology • Uses a true physical ring or a physical star topology

27. FDDI Connectors • FDDI connectors are unique • Later versions use CAT 5 UTP (CDDI) and copper instead of fiber • FDDI segments can be two kilometers between stations with a maximum ring size of 100 kilometers

28. ATM • Asynchronous Transfer Mode (ATM) runs at 155 Mbps using fiber optic cabling or CAT 5 UTP • Physical star topology • Two fiber connectors per node • CAT 5 or better cabling with RJ-45 connectors • ATM uses fixed-length packets on a point-to-point connection and is popular for WAN connections