Cisco Cisco Packet Data Gateway (PDG) Ratgeber Für Administratoren
Congestion Control
▀ Overview
▄ Cisco ASR 5500 System Administration Guide
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Overview
Congestion Control monitors the system for conditions that could potentially degrade performance when the system is
under heavy load. Typically, these conditions are temporary (for example, high CPU or memory utilization) and are
quickly resolved. However, continuous or large numbers of these conditions within a specific time interval may impact
the system’s ability to service subscriber sessions. Congestion control helps identify such conditions and invokes
policies for addressing the situation.
under heavy load. Typically, these conditions are temporary (for example, high CPU or memory utilization) and are
quickly resolved. However, continuous or large numbers of these conditions within a specific time interval may impact
the system’s ability to service subscriber sessions. Congestion control helps identify such conditions and invokes
policies for addressing the situation.
Congestion control operation is based on configuring the following:
Congestion Condition Thresholds: Thresholds dictate the conditions for which congestion control is enabled
and establishes limits for defining the state of the system (congested or clear). These thresholds function in a
way similar to operation thresholds that are configured for the system as described in the Thresholding
Configuration Guide. The primary difference is that when congestion thresholds are reached, a service
congestion policy and an SNMP trap (starCongestion) are generated.
way similar to operation thresholds that are configured for the system as described in the Thresholding
Configuration Guide. The primary difference is that when congestion thresholds are reached, a service
congestion policy and an SNMP trap (starCongestion) are generated.
A threshold tolerance dictates the percentage under the configured threshold that must be reached in order for
the condition to be cleared. An SNMP trap, starCongestionClear, is then triggered.
the condition to be cleared. An SNMP trap, starCongestionClear, is then triggered.
Port Utilization Thresholds: If you set a port utilization threshold, when the average utilization of all
ports in the system reaches the specified threshold, congestion control is enabled.
Port-specific Thresholds: If you set port-specific thresholds, when any individual port-specific
threshold is reached, congestion control is enabled system-wide.
Service Congestion Policies: Congestion policies are configurable for each service. These policies dictate how
services respond when the system detects that a congestion condition threshold has been crossed.
Important:
This section provides the minimum instruction set for configuring congestion control. Commands
that configure additional interface or port properties are provided in Subscriber Configuration Mode in the Command
Line Interface Reference. Always refer to the Administration Guides for all of the licensed products running on this
platform for additional configuration information with respect to congestion control. Congesiton control functionality
varies based on product and StarOS version.
Line Interface Reference. Always refer to the Administration Guides for all of the licensed products running on this
platform for additional configuration information with respect to congestion control. Congesiton control functionality
varies based on product and StarOS version.
For the MME three levels of congestion control thresholds are supported – critical, major and minor. By default only the
critical threshold is supported for other products. SNMP traps also support major and minor congestion control
thresholds. A set of congestion-action-profile commands allows an operator to establish additional actions to be taken
for specific thresholds and threshold levels.
critical threshold is supported for other products. SNMP traps also support major and minor congestion control
thresholds. A set of congestion-action-profile commands allows an operator to establish additional actions to be taken
for specific thresholds and threshold levels.