Installing and Administering HP FDDI/9000 Software

30 Chapter 1
FDDI Resources
FDDI Concepts
FDDI Single-Attached Stations
Figure 1-5 shows the data path through the concentrator after one of the
workstations has been detached from the FDDI network. In this case the
fault tolerant capability of the concentrator enables the station that is
not operational to be bypassed.
Figure 1-5 FDDI Single Attached Station When Bypassed
FDDI Error Detection
The FDDI Link Error Monitor (LEM) is a fault detection service that
continually examines the Link Error Rate (LER) of an active link. The
detector function of the LEM monitors the link quality and identifies link
error events. Whenever the link error rate exceeds the predetermined
cutoff threshold, the link is automatically removed from the ring. The
Link Error Rate Estimate (LER_Estimate) provides the long term
average link error rate. (Refer to the fddistat(1M) manpage for more
information.)
M3
B
S
A
M2
M1
Concentrator (DAC Ports)
MAC Address =
080009001023
DAS = Dual Attach Station
DAC = Dual Attach Concentrator
A, B, M and S = Port Types
Series 800 System (SAS)
CF_State = Wrap_S
MAC Address =
080009009087
MAC
Model 755 Wkstn (SAS)
CF_State = Isolated
MAC Address =
080009006054
MAC
S
MAC
S
MAC
Model 735 Wkstn (SAS)
CF_State = Wrap_S
MAC Address =
080009005043