Token Ring
6-12
Description
Token Ring Network Rules
Token Ring networks are available in two types, which are differentiated by the
speed at which data is passed from station to station: 4 Mbps and 16 Mbps. In the
first years of its inception, a 1 Mbps Token Ring standard was also available, but it
has fallen into disuse with the availability of the higher-speed Token Ring
standards. The Cabletron Systems Token Ring product line offers great flexibility
to customers, including the ability, on all Token Ring modules, to select which of
the two common ring speeds, 4 Mbps or 16 Mbps, the ring will utilize. Token Ring
physical media are nearly as diverse as Ethernet media. Token Ring networks
may utilize shielded or unshielded twisted pair, or fiber optic cabling.
The type of cabling used and the speed of throughput are deciding factors in the
limitations of Token Ring networks. Each Token Ring has a maximum number of
stations that can be configured on it, and a maximum distance between Token
Ring stations. These limiting factors are portions of the current IEEE 802.5 Token
Ring standard, and may be found later in this section, as well as in the Charts and
Tables section at the end of this guide. You can see by looking at the chart that as
the cabling quality decreases and the network speed increases, the maximum
number of stations and their maximum distance from each other drops
dramatically. Don’t be concerned at this point with the small table detailing what
are called Ring-In/Ring-Out distances; we will cover those soon. You can see that
Token Ring has very detailed requirements for its network configurations.
As an example, a facility needs to put 200 people on a single Token Ring at 16
Mbps. Looking at the chart, we see that the only way that we can accommodate
this on a single ring is with IBM Type 1 or Type 2 Shielded Twisted Pair (STP)
cabling utilizing what is called “active” circuitry. This cabling allows us to run 150
meters from the hub. If the customer wanted to use Unshielded Twisted Pair
(UTP) cabling at 16 Mbps, it would not be possible to put all 200 stations on the
one Token Ring. In that case, a new ring would have to be created. How we go
about modifying Token Ring networks to accommodate greater user numbers and
longer cable distances is covered later.
Summary of Contents for MMAC-5FNB
Page 1: ...Cabletron Systems Networking Guide MMAC FNB Solutions ...
Page 2: ......
Page 4: ...ii ...
Page 10: ...viii ...
Page 188: ...Expansion Ethernet 8 12 Port Assignment and Virtual LANs ...
Page 194: ...Expansion Token Ring 9 6 Port Assignment ...