Beta Draft Confidential
4-30
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
Configuring ATM Logical Ports on Frame-based Modules
Defining ATM UNI DCE/DTE Logical Ports
Closed Loop
Congestion Control
Closed Loop Enabled – Enables OSPF closed loop congestion
control to reduce the rate of excess data in the network during
congested periods. Using OSPF the trunk’s congestion state is
communicated to all switches in the network.
Amber Pm – Enter the reduction percentage of Be when mild
congestion occurs. The default value is 50%.
Amber Ps – Enter the reduction percentage of Be when severe
congestion occurs. The default value is 75%
Check Interval – (congestion state check interval) Enter an interval
that determines the number of seconds in which the switch monitors
the trunk’s congestion on the port. The default value is 1 second.
Bad PVC Factor
– Enter a value between 0-32 to determine the
threshold for “bad” PVC detection. The default value is 30.
The following example shows the relationship between the “bad”
PVC factor and threshold.
Note: If you select simple as the rate enforcement scheme, this
feature is disabled.
Clear Delay – (congestion state clear delay) Enter a value that
determines the number of seconds in which the switch monitors the
trunk’s congestion on the port. The default value is 3 seconds.
Call Admission
Control
Select this check box to reserve a percentage of bandwidth in the
VBR-NRT QoS class for ILMI.
Clear the check box to (default) release the bandwidth from a
reserved status. If the attached device cannot run ILMI, leave ILMI
disabled.
Note: To use line loopback diagnostics, you must disable ILMI
support. See the Switch Diagnostics User’s Guide for CBX 3500,
CBX 500, GX 550, and B-STDX 9000 for more information.
CIR Policing
An indicator for committed information rate (CIR) policing for
Frame Relay UNI and NNI Lports only.
Enable (default) – When a circuit exceeds the established
committed information rate (CIR), the Discard Eligible (DE) bit in
the Frame Relay header is set on for incoming frames that exceed
the CIR.
Disable – The DE bit is not changed for incoming frames.
Note: Whenever the network is congested, frames with the DE bit set
on are discarded first.
Table 4-11.
Add Logical Port: Congestion Control Tab Fields (Continued)
Field
Action/Description
Threshold
=
2
32 F
–
b
(
)
Bc+(Be/2)
Содержание CBX 3500
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