Beta Draft Confidential
Configuring ATM Over MPLS Trunks
Configuring ATMoMPLS Trunk Logical Ports
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000 1/19/058-41
Routing Metric The routing metric configured for the logical port. Routing
metrics allow the switch to select less congested paths and
avoid congested paths when transferring data.
Routing metric options are:
• Cell/Frame Delay Variation – Measures the average
variation in delay between one cell/frame and the next,
measured in fractions of a second. When emulating a
circuit, cell/frame delay variation measurements allow the
network to determine if cells are arriving too fast or too
slow.
• End-to-End Delay – Measures the time (propagation and
transmission delay) it takes a cell/frame to get from one end
of a connection to the other. It is measured when the port
initially comes up; it does not include queueing delays, so it
does not affect port congestion.
• Admin Cost – Measures the administrative cost associated
with the logical port. The administrative cost is specified by
the administrator, enabling you to adjust path selection
manually.
Note: For Frame Relay, routing metrics apply only if the port is
configured as a UNI DCE or UNI DTE logical port.
Oversubscription % A minimum value of 100% to indicate the virtual bandwidth
available for a service class. A value of 100% ensures that the
port will deliver all user data for that service class without
unanticipated delays or excessive cell loss. A value of 200%
effectively doubles the virtual bandwidth available for that
service class. However, if all network traffic attempts to use the
network resources at precisely the same time (for example,
during multiple file transfer sessions over the same trunk),
some traffic may be delayed or dropped.
Note: The Oversubscription value for CBR (for ATM) and CFR
(for Frame Relay) is always set at 100% and cannot be
modified.
Table 8-12. Add Logical Port: QoS Tab Fields (Continued)
Column Action/Description
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