Cisco Cisco Packet Data Gateway (PDG)

 

▄  SaMOG Administration Guide, StarOS Release 19 

used. Regardless, the directory can be on a local file system or on an NFS-mounted file system on the Web Element 
Manager server. 

  For more information on bulk statistics, see the System Administration Guide. 

SaMOG enhances on the StarOS framework to provide congestion control policies and threshold crossing alerts to 
ensure smooth performance of the SaMOG service and prevent congestion. The Congestion Control feature enables 
policies and thresholds to be configured to specify how the system should react in the event of a heavy load condition. 

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 have an 
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: 

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Congestion Condition Thresholds: Thresholds dictate the conditions for which congestion control is enabled 

and establish limits for defining the state of the system (congested or clear). These thresholds function in a way 
similar to operational 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. 

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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. 

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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. 

For the SaMOG Gateway, congestion control monitors the following resources: 

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Licensing utilization 

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Maximum sessions per service utilization 

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Demux message queue utilization 

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Demux message queue wait time 

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Port Rx specific utilization 

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Port Tx specific utilization 

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Average transmit port Tx utilization 

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Process CPU utilization 

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System CPU utilization 

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System memory utilization