Cabletron Systems 24 Benutzerhandbuch

 

Page 1-5

 

By default, each of the STH hub’s TCU ports is configured to its STN 
(station) setting to support concentrator lobe connections to stations. 
Through Local Management, any TCU port may be reconfigured to its 
RO (Ring Out) setting to support connections to passive MAU (Multi-
Station Access Unit) workgroups. 

 

The STH provides enhanced reliability for existing networks which use 
passive MAUs because Multiple Ring Out TCUs allow for the separate 
attachment of each MAU. Rather than daisy-chaining MAUs together as a 
single entity and risking their collective isolation in case of beaconing, the 
user can now attach each MAU individually, reducing the number of 
MAU ports that are at risk of collective isolation in case of beaconing on 
the ring; ABRP is able to bypass individually connected MAUs on an 
individual rather than collective basis. See Figure 1-2.

 

The STH hub’s Ring Out TCU configuration does not provide for the 
MAU’s redundant connection to the ring. In the common configuration, a 
MAU chain is dual-attached to the Token Ring LAN via both a Ring Out 
cable and a Ring In cable. Using a TCU port, however, each passive MAU 
workgroup is physically connected to the hub in the same manner as a 
station—by a single cable—and therefore is not provided a backup path 
between the MAU and the Token Ring network. Only the dual 
attachment of Ring In 

 

 Ring Out cables can provide a backup path. 

This level of connectivity must be provided by a dedicated pair of Ring In 
/ Ring Out ports such as those available on the intelligent hub.

 

Use the 

 

 (PN 9031390) and the 

 

 (PN 9031320) to supplement the procedures and other 

technical data provided in this manual.