CHAPTER
Practical Token Ring
Implementation
Chapter Objectives
• Give an overview of the Token Ring LAN
• Describe the characteristics of the Token Ring
LAN
• Discuss the implementation of Token Ring
LANs with illustrations of the LAN
components and connections
• Provide notes on the actual implementation
of the LAN in buildings
Chapter Modules
• An Overview of Token Ring LANs
• Token Ring Basic Characteristics
• Implementation of Token Ring
• More notes on implementation
MODULE
An Overview of Token Ring
LANs
Module Objectives
• Define Token Ring networks
• Trace the origin of Token Ring
• Discuss the current status and usage
• Provide an illustration of a typical
Token Ring configuration
• Present actual Token Ring
implementations
Token Ring Defined
• Token Ring is a standardized and
efficient network
• Based on the token passing protocol
• Conforms to the IEEE 802.5 standard
Token Ring Origin
• Introduced by IBM in 1984 for
connecting the following:
– Personal computers
– Mid-range computers
– Mainframe computers
• Current position with IBM
– Part of the SNA specification for
interconnection related to IBM products
Current Status of Token Ring
Technology
• Standardized
– IEEE 802.5
• Becoming overshadowed by Ethernet
for LAN applications due the following
reasons
– Higher speeds of Ethernet
– Lower cost of Ethernet
• Ethernet cabling borrows from the
telecommunication industry, hence it is
cheaper
Current Usage
• In the 4-16 Mbps range, the token ring
remains an efficient LAN technology
• 100 Mbps Token Ring networks are now used
in the field
• Token ring technology is used for the
backbone in large networks where the
operating speed is in the range of 100 Mbps
– An example is FDDI
A Typical Token Ring LAN
Configuration
Special IBM
Connectors Muti-Station
Access Unit
IBM Type 1
Twisted Pair
9-Pin AUI Connectors
Client
Client
Server
An Actual 4 Mbps Token Ring
Implementation
Source:
Blackbox Corporation
An Actual 16 Mbps Token Ring
Implementation
Source:
Blackbox Corporation
END OF MODULE
MODULE
Token Ring Basic Characteristics
Module Objectives
• Logical an physical topologies and
implementation
• Cabling
• Access method, speed and transmission
• Frame format
Topology
• Logical
– Ring
• Physical
– Star
Logical and Physical
Implementation
Physical Implementation
Logical Functioning
Cabling
• Shielded or unshielded Twisted Pair
• IBM
– Types 1, 2, 3 etc.
• Others
Access Method, Speed and
Transmission
• Access method
– Token passing
• IEEE standard
– IEEE 802.5
• Speed
– 4M, 16M and 100M bps
• Transmission
– Baseband
Token Passing Access Method
Token
Acknowledgment
Origin
Destination
Data Delivery
Frame Format
Start
Frame
Control
Source Address
Frame Check
Sequence
Data
Access
Control
Destination
Address
End
Delimiter
Frame
Status
END OF MODULE
MODULE
Implementation of Token Ring
Module Objectives
• Token Ring hardware requirements
• Actual implementation hardware
• Implementation rules
Token Ring Implementation
Hardware
• Token ring NIC
• Cable
– IBM Type 1 or 2 or 3/ or UTP as needed by the
design
• Multistation Access Unit (MAU)
– Multistation Access Unit (MSAU)
– Smart Multistation Access Unit (SMAU)
– Incorporates bypass mechanism for fault tolerance
Actual Implementation
Hardware
Token Ring Implementation
Rules: For IBM Rings and Hubs
• Maximum number of hubs on a ring
– 33
• Maximum number of computers on
MSAU-based networks
– 72 with unshielded cable
– 260 with shielded cable
Multi-Hub Rings
Ring
Out
Ring
In
Ring
Out
Ring
In
Token Ring Implementation
Rules: Cable Length
• Maximum station distance from MSAU
– 330 feet for Type 1
– 328 feet for STP
– 148 feet for UTP
• Minimum length from MSAU
– 8 feet
• Maximum distance between MSAUs
– 500 feet
Distance Limitation Illustrated
<500’
Type 1
<330’
UTP
<148’
STP
<328’
END OF MODULE
MODULE
More Notes on Implementation
Module Objectives
• Implementation in a building
• Use of telephone wiring for
implementation
• Notes on connectors and media filters
• Use of fiber optics to extend the length
of the connection between a MSAU and
a node
Implementation in a Building
Backbone
MSAU
Client
Hub
MSAU
Wiring Rack
(Wiring Closet)
Client
IBM
Type 1
Server
Notes on Installation in a
Building
• Wiring closet is a reserved space in the
building for housing wiring hubs
• Wiring rack
• MSAUs
The Use of Installed Telephone
Wiring for Token Ring
MSAU
Patch
Panel
Telephone
Punch-down
Block
Media
Filter
RJ 11/
RJ45
Desktop
Notes on Connectors
• Regular connector
– AUI
– MIC
• Telephone line connectors
– RJ-45 (8-pin)
– RJ-11 (4-pin)
– Require media filter interface for
connection to the Token Ring NIC
Media Filter
Notes on Cable Extension
• Patch cables
– Used for extending the length of a cable
– Uses IBM MIC connectors
• Repeaters
– To extend beyond regular cable length
limitation
– Distances can be extended using fiber optic
extenders as well
Fiber-Optic Extender
END OF MODULE
END OF CHAPTER