Specifications

B.4 Station Configurations
B–6 FDDI Overview
B.4 Station Configurations
B.4.1 Identifying Stations and Concentrators
Stations and Concentrators (see Figure B–3) can be identified by the types of ports
that they use to attach to other stations:
• A and B Ports — Dual Attachment Stations have A and B ports for attachment to
other stations in the dual ring, or to concentrator M ports.
• M Port — All concentrators, (SAC or DAC), are identifiable by the presence of
M ports. The M port allows the attachment of other stations or concentrators.
• S Port — If the concentrator also has an S port, it is a SAC; if it has A and B
ports it is a DAC. A Single Attachment Station has an S port for connection to a
concentrator M port.
Figure B–3 FDDI Port Types
LKG-10097-96F
AB
DAS
AB
DAS
AB
DAS
BA
DAS
BA
DAC
BA
DAC
M
S
M
SAC
S
SAS
S
SAS
M