Cabletron Systems STHI manual TCU Ports, Lobe Port and Multiple Ring Out Port Configurations

STHI Overview

1.2.2TCU Ports

The four STHI models are functionally identical with the exception of the number and type of network ports they offer:

Table 1-1. TCUs and Media Types per Model

STHI-22	12 unshielded RJ45 ports
STHI-24	24 unshielded RJ45 ports
STHI-42	12 shielded RJ45 ports
STHI-44	24 shielded RJ45 ports

Each STHI is equipped with TCU ports fitted with female RJ45 modular connector jacks to support the attachment of either STP (shielded twisted pair) or UTP (unshielded twisted pair) cabling with RJ45 connector plugs. Models that support STP cabling use RJ45 connectors that provide a grounded connection for the cabling shield. See Section 2.2.2, TCU and COM Ports, for pinouts.

Lobe Port and Multiple Ring Out Port Configurations 1

Each TCU port on the STHI is internally defaulted to operate as a lobe interface to support the insertion of a Token Ring station into a ring. However, each TCU port may also be reconfigured via the Local Management (LM) application (see Section 5.6.3, Port Configuration Fields) to function as a Ring Out port which will support connections to non-intelligent, passive MAU (Multi-Station Access Unit) workgroups.

Refer also to Section 1.2.6, Support for Passive MAU Workgroups.

Ring Speed Fault Protection 2

STHI hubs also provide Ring Speed Fault Protection on each TCU port to protect against beaconing conditions caused by stations inserting at the wrong ring speed. If a ring speed mismatch is detected, the STHI blocks the port to keep the misconfigured station isolated from the ring and provides a simple visible LED signal (blinking red at the port’s LED) to indicate that Ring Speed Fault Protection is blocking the port. The port remains blocked until the ring speed mismatch condition is removed or resolved.

Page 1-3