ZyXEL Communications VMG8825-B Series User Manual page 306

from data cells by a predefinded Payload Type Identifier (PTI) in the cell header. Both F4 flows and F5
flows are bidirectional and have two types.
• segment F4 flows (VCI=3)
• end-to-end F4 flows (VCI=4)
• segment F5 flows (PTI=100)
• end-to-end F5 flows (PTI=101)
OAM F4 or F5 tests are used to check virtual path or virtual channel availability between two DSL
devices. Segment flows are terminated at the connecting point which terminates a VP or VC segment.
End-to-end flows are terminated at the end point of a VP or VC connection, where an ATM link is
terminated. Segment loopback tests allow you to verify integrity of a PVC to the nearest neighboring
ATM device. End-to-end loopback tests allow you to verify integrity of an end-to-end PVC.
Note: The DSLAM to which the VMG is connected must also support ATM F4 and/or F5 to use
this test.
Note: This screen is available only when you configure an ATM layer-2 interface.
Figure 193 Maintenance > Diagnostic > OAM Ping
The following table describes the fields on this screen.
Table 148 Maintenance > Diagnostic > OAM Ping
LABEL DESCRIPTION
Select a PVC on which you want to perform the loopback test.
F4 segment Press this to perform an OAM F4 segment loopback test.
F4 end-end Press this to perform an OAM F4 end-to-end loopback test.
F5 segment Press this to perform an OAM F5 segment loopback test.
F5 end-end Press this to perform an OAM F5 end-to-end loopback test.
Chapter 42 Diagnostic
VMG8825-B Series User's Guide
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