3Com 3C780 - LinkBuilder FDDI Base Unit User Manual page 29

Ring wrap
Figure 1-1. Ring Wrap
The FDDI standard developed by the American National Standards Institute
(ANSI) defines four protocols:
Physical Medium Dependent (PMD)
Physical (PHY)
Media Access Control (MAC)
Station Management (SMT)
Each of these protocols is briefly defined below.
Break in ring or station failure
Ring wrap
Overview
1-3
Primary ring
Secondary ring