Cabletron Systems switches - Manual (Page 19)

Token Ring 2-7
Review of Networking
Token Ring networks can use a variety of physical cabling, including Unshielded
Twisted Pair (UTP), Shielded Twisted Pair (STP), or fiber optic cabling. The
characteristics of the various cables can directly impact the operational limitations
of a Token Ring network which uses a particular media.
• Lobe Cable Lengths for 4 Mbps Token Rings: The operation of a 4 Mbps Token
Ring network imposes some relatively generous limitations on the maximum
length of any station cable (also called a lobe cable) connected to an active port
in the network as shown in the following list:
- IBM Types 1, 2 STP: 300 m
- IBM Types 6, 9 STP: 200 m
- Category 5 UTP: 250 m
- Categories 3, 4 UTP: 200 m
- Multimode Fiber Optics: 2000 m
- Single Mode Fiber Optics: 2000 m
• Lobe Cable Lengths for 16 Mbps Token Rings: 16 Mbps Token Ring networks
also impose limitations on the maximum length of any media connected to an
active port as shown in the following list:
- IBM Types 1, 2 STP: 150 m
- IBM Types 6, 9 STP: 100 m
- Category 5 UTP: 120 m
- Categories 3, 4 UTP: 100 m
- Multimode Fiber Optics: 2000 m
- Single Mode Fiber Optics: 2000 m
• RI/RO Cable Lengths for 4 Mbps Token Rings: 4 Mbps Token Ring networks
also require that Ring-In/Ring-Out (RI/RO) connections be no longer than a
certain amount. This amount is dependent upon the media being used for the
RI/RO connection as shown in the following list:
- IBM Types 1, 2 STP: 770 m
- Category 5 UTP: 250 m
- Categories 3, 4 UTP: 200 m
- Multimode Fiber Optics: 2000 m
- Single Mode Fiber Optics: 2000 m
• RI/RO Cable Lengths for 16 Mbps Token Rings: 16 Mbps Token Ring networks
also require that Ring-In/Ring-Out (RI/RO) connections not exceed the
lengths given below:
- IBM Types 1, 2 STP: 346 m
- Category 5 UTP: 120 m
- Categories 3, 4 UTP: 100 m
- Multimode Fiber Optics: 2000 m
- Single Mode Fiber Optics: 2000 m