NETWORK TUTORIALS: Token Ring

IEEE 802.5 specification.
Star wired ring topology (logical ring)
Uses token passing access method.
Can have higher transmission speeds than Ethernet
It has larger frames than Ethernet => more can get transferred over the wire in any given time.
Uses IBM STP Types 1, 2 and 3 cabling. (Can be UTP)
Transmits at 4 and 16 Mbps. (16 Mbps cards will slow down to 4 Mbps if put on that kind of network, but the 4 Mbps cards can't speed up.
Baseband transmission
Data travels in one direction only
Each computer acts as a unidirectional repeater
Deterministic method of cable access. Computers cannot use the cable unless they have the token. Therefore, computers can't force their way onto the network like CSMA/CD (Ethernet)
First computer online is assigned to monitor network activity.

Multistation Access Units (MAU's)
Multistation Access Units (MSAU's)
Smart Multistation Access Units (SMAU's)
Computers attach directly to the MSAU in a physical star to form a logical ring.
Each MSAU has 10 connection ports ==> can support 8 clients with 2 ports for ring in and ring out.
Each ring can have as many as 33 MSAU's

Up to 12 MSAU's can connect to each other
The MSAU can sense if a computer is down and then disconnect it from the ring => built-in fault tolerance
Cabling

Token ring networks are well suited to fiber optic cable: data travels in only one direction in it.

Here are some limitations of Token Ring:

The maximum number of workstations is 260 on Type 1 or fiber optic cable at 16 Mbps.
The maximum number of workstations is 72 on Type 3 cable at 4 Mbps.
The distance between MSAUs (Multistation Access Units) is 100 meters (Type 1 cabling) to 45 meters (Type 2 cabling).
Each ring can have up to 33 MSAUs.
Maximum distance of the ring is 4 kilometers with fiber optic cable.

Token Ring and Ethernet Comparison
Token Ring

NETWORK TUTORIALS