1. User's Guide
  2. Agent Configuration
  3. About Traffic Constraints

About Traffic Constraints

You use traffic constraint configuration to establish call admission control (CAC) thresholds and triggers that determine whether the OECB can accept and process network traffic, including calls. The OECB provides call CAC based on the following policies:

  • Bandwidth
  • Session capacity
  • Session rate

Bandwidth-Based Admission Control

The OECB is a policy enforcement point for bandwidth-based call admission control. Sessions are admitted or rejected based on bandwidth policies, configured on the OECB for each agent.

As the OECB processes call requests to and from a particular agent, the bandwidth consumed by the traffic is decremented from its bandwidth pool.

Session Capacity- and Rate-based Admission Control

A session agent defines a signaling endpoint. It is a next hop signaling entity that can be configured to apply traffic shaping attributes. You can define concurrent session capacity and rate attributes for each session agent.

You can configure a set of attributes and constraints for each session agent to support session access control. And you can set up session admission control so that the OECB limits the number of concurrent inbound and outbound sessions for any known service element.

The OECB denies a call request to any destination that has exceeded its configured policies for session capacity and session rate. The OECB might reject the call request back to the originator. If multiple destinations are available, the Oracle Enterprise Communications Broker checks current capacity and rate for each destination and attempt to route the call only to destinations whose policy limits have not been reached.

CAC Utilization Statistics via SNMP

The OECB allows you to retrieve information on current session utilization and burst rate as a percentage of their configured maximums on per session-agent basis. The OECB uses the configured max-session and max-burst-rate settings in conjunction with a percentage formula to calculate this value. The system also uses a configuration setting to establish the threshold at which trap and trap clear messages are sent from the SNMP agent to the configured manager(s). You must configure traps and enable the SNMP Monitor Traps parameter for this functionality.

You must load the MIB version associated with this software version on all pertinent SNMP managers to query these CAC utilization (occupancy) values and interpret the traps. In addition, the user must configure the threshold at which the system generates the CAC utilization trap. Note that the corresponding clear trap uses the same threshold setting, sending the clear trap when utilization falls below 90% of the threshold.

The OECB can issue a trap when either the value of max-session or CAC burst rate exceeds a configured value. The system only sends one trap when the threshold is exceeded. When the value falls back under 90% of this threshold, the OECB sends a clear trap.

You configure the value that triggers these traps as a percentage of the max-session and max-burst-rate settings configured for the applicable session agent. The system uses the same setting to specify when to send both the sessions and burst rate traps. The name of this parameter is the cac-trap-threshold. You must express the value as a number less than 100. There is no default setting; the system does not generate a trap if you have not configured this setting.

The apSipCACUtilAlertTrap identifies the threshold exceeded on a per-element and per-value (session count or burst rate) for each trap, including:

  • apSipSaCacSessionUtilLevel
  • apSipSaCacBurstRateUtilLevel