Allied Telesis AT-S65 - Manual (Page 81)

AT-S65 Management Software User’s Guide
81
In mode 4, the third missing link mode (Figure 38), missing link is disabled
on both the port and line sides. Case A shows that if there is no received
signal at the port (SFP) side then the line side loops back to itself. Case C
shows that if there is no received signal on the WDM (line) siden then the
port (SFP) side loops back to itself.
Figure 38. Mode 4: Missing Link Disabled for Port and Line Sides
Fixed Loopback
Mode
In fixed loopback mode, the data paths are fixed. Fixed loopback operates
in one of three ways: loopback on the port (SFP) side only (Figure 39),
loopback on both the port and line sides (Figure 40), or loopback on the
line side only (Figure 41).
CWDM
Transciever
SFP
Line
Side
Port
Side
CWDM
Transciever
SFP
Line
Side
Port
Side
CWDM
Transciever
SFP
Line
Side
Port
Side
CWDM
Transciever
SFP
Line
Side
Port
Side
X X X
X X
X X X
Legend
No optical signal
Optical signal present
Case B:
Port side: optical
signal received
Line side: optical
signal received Case C:
Port side: optical signal
received
Line side: no optical
signal received Case D:
Port side: no optical
signal received
Line side: no optical
signal received Case A:
Port side: no optical
signal received
Line side: optical signal
received