Specifications
iii
CONTENTS
CHAPTER 1 INTRODUCTION
USING THIS MANUAL.................................................................................................... 1-1
RECOMMENDED READING.......................................................................................... 1-1
CHAPTER 2 TOKEN RING OVERVIEW
INTRODUCTION............................................................................................................. 2-1
TOKEN RING TOPOLOGY............................................................................................. 2-2
LOCAL AREA NETWORK STANDARDS........................................................................ 2-3
Open Systems Interconnect (OSI) Model................................................................. 2-3
Access Method ......................................................................................................... 2-6
Advantages of Token Ring........................................................................................ 2-7
Disadvantages of Token Ring ................................................................................... 2-7
PHYSICAL LAYER.......................................................................................................... 2-8
Physical Layer Signaling Technique........................................................................ 2-10
Active Monitor......................................................................................................... 2-11
Latency ................................................................................................................... 2-12
Signal Timing.......................................................................................................... 2-12
Accumulated Jitter .................................................................................................. 2-12
Ring Latency........................................................................................................... 2-13
TOKEN RING PROTOCOL OPERATION ..................................................................... 2-13
Station Insertion...................................................................................................... 2-14
Lobe Test.......................................................................................................... 2-14
Physical Insertion............................................................................................. 2-14
Address Veriļ¬cation.......................................................................................... 2-14
Ring Poll Process............................................................................................. 2-15
Request Initialization........................................................................................ 2-15
The Active Monitor.................................................................................................. 2-15
The Standby Monitor .............................................................................................. 2-16
Monitor Contention Process ................................................................................... 2-16
Claim Token...................................................................................................... 2-16
Frame Transmission................................................................................................ 2-17
Access Priority ................................................................................................. 2-17
Stacking Station ............................................................................................... 2-18
Ring Management .................................................................................................. 2-18
Purging the Ring .............................................................................................. 2-18
Beaconing ........................................................................................................ 2-19
Beacon Receive (Auto Removal) ..................................................................... 2-19
SOURCE-ROUTE BRIDGING METHOD...................................................................... 2-20
Route Discovery ..................................................................................................... 2-20
Source Routing....................................................................................................... 2-21
Bridge and Ring Numbering ................................................................................... 2-21
Control Field..................................................................................................... 2-21