5
9F426-03 Module Specific Information
The Ring Map
The Ring Map shows a series of addresses in upstream/downstream order. These
addresses, which represent each FDDI device attached to the ring, are arranged
on the screen to simulate the circular fashion of a ring. When first displayed, the
station at the upper left corner of this map is your current station. The screen
displays node class, node address, and twisted and/or wrapped conditions (T for
twisted, W for wrapped). The node class possibilities are:
•
NAS (Null Attached Station) - Isolated station; station not connected to an
FDDI ring.
•
DAS (Dual Attached Station) - Station that does not support M ports, but
connects directly to an FDDI primary and secondary ring using A and B ports.
•
DAC (Dual Attached Concentrator) - Station that supports M ports and
connects directly to an FDDI primary and secondary ring using A and B ports.
•
SAS (Single Attached Station) - Station that accesses the main ring through a
concentrator, creating a ring of trees topology.
•
SAC (Single Attached Concentrator) - Station that accesses the main ring
through another concentrator and, in turn, allows the connection of more
devices. SACs provide the same connections as DACs, without attaching to the
dual ring.
•
NAC (Null Attached Concentrator) - Isolated concentrator; concentrator not
connected to an FDDI ring.
While the map is updated, for example, during a ring topology change, the screen
may show ??:??:??:??:??:?? to illustrate an undetermined address.
Displaying the Ring Map Node Screen
To display the Ring Map Node Screen (from the Ring Map Configuration Screen),
use the arrow keys to highlight an address, then press the Return key. The Ring
Map Node Screen appears.
The Ring Map display stops at the first occurrence of an undetermined address,
and does not display any known information beyond this point.
NOTE
