Cabletron Systems bridges Manuel D’Utilisation
Token Ring Workgroup Design
8-5
Token Ring
This extension of the ring can be used to allow the Token Ring network to connect
widely-separated groups of stations in a single ring, or can be used to support
greater numbers of users than a single Token Ring stack can accommodate. A
Token Ring stack of maximum size will provide for the connection of 120 stations,
well below the 250 station maximum of the IEEE 802.5 standard for some cabling
types. If a Network Designer faced a situation in which a maximum-size stack
had not been able to support all the required connections, the addition of an
RI/RO link between the full stack and a new stack would allow the network to
support up to another 120 stations.
widely-separated groups of stations in a single ring, or can be used to support
greater numbers of users than a single Token Ring stack can accommodate. A
Token Ring stack of maximum size will provide for the connection of 120 stations,
well below the 250 station maximum of the IEEE 802.5 standard for some cabling
types. If a Network Designer faced a situation in which a maximum-size stack
had not been able to support all the required connections, the addition of an
RI/RO link between the full stack and a new stack would allow the network to
support up to another 120 stations.
These RI/RO connections for ring extension are made using specialized PIMs
called TPIMs, or Token Ring Port Interface Modules.
called TPIMs, or Token Ring Port Interface Modules.
Design Example
The following example traces the design of a small office network. The network is
intended for a newly-formed Health Maintenance Organization (HMO), and
consists of a series of related departments, each having nearly equal demands of
the network. The Network Designer has examined the needs of the end users and
the organization of the stations and facility, and has decided that a single, 16Mbps
Token Ring network will offer the necessary performance and reliability to this
network. The cabling to be used will be Category 5 UTP cable, and all the cable
runs have been determined to be within the limitations of the Token Ring
networking technology.
intended for a newly-formed Health Maintenance Organization (HMO), and
consists of a series of related departments, each having nearly equal demands of
the network. The Network Designer has examined the needs of the end users and
the organization of the stations and facility, and has decided that a single, 16Mbps
Token Ring network will offer the necessary performance and reliability to this
network. The cabling to be used will be Category 5 UTP cable, and all the cable
runs have been determined to be within the limitations of the Token Ring
networking technology.
The HMO network will consist of 45 stations: 15 office receptionists, 12 doctors’
offices, 3 pharmacy stations, 3 records stations, 8 accounting and billing stations,
and 4 management personnel. None of these stations has any particular
importance over others from the point of view of the Network Designer, and there
is currently no desire to provide internetworking capabilities or segmentation to
the network.
offices, 3 pharmacy stations, 3 records stations, 8 accounting and billing stations,
and 4 management personnel. None of these stations has any particular
importance over others from the point of view of the Network Designer, and there
is currently no desire to provide internetworking capabilities or segmentation to
the network.
Examining the first networking device selection criteria, the Network Designer,
who is familiar with the use of both SNMP and RMON as diagnostic and
fault-aversion tools, opts to investigate the short-term cost savings that would be
provided by selecting the STHI series of Token Ring concentrators rather than the
MicroMMAC-T series of concentrators. The Network Designer eliminates the
non-intelligent devices and those devices which provide management functions
more extensive than SNMP. The resulting selection field is summarized below.
who is familiar with the use of both SNMP and RMON as diagnostic and
fault-aversion tools, opts to investigate the short-term cost savings that would be
provided by selecting the STHI series of Token Ring concentrators rather than the
MicroMMAC-T series of concentrators. The Network Designer eliminates the
non-intelligent devices and those devices which provide management functions
more extensive than SNMP. The resulting selection field is summarized below.
NOTE
Management functionality provided by an intelligent stack base
is not distributed to non-intelligent devices that are connected
to that base through RI/RO ports.
is not distributed to non-intelligent devices that are connected
to that base through RI/RO ports.