Using SNMP to Configure DiffServ VoIP Support

  1. Use the agentDiffServGenStatusAdminMode object in agentDiffServGenStatusGroup under fastPathQOSDiffServPrivate in the FASTPATH-QOS-DIFFSERV-PRIVATE-MIB module to activate DiffServ for the switch.
  2. To set queue 5 on all ports to use strict priority mode, use the agentCosQueueSchedulerType in the agentCosQueueTable in the FASTPATH-QOS-COS-MIB module. This queue is used for all VoIP packets.
  3. Use the agentDiffServClassRowStatus object in the agentDiffServClassTable to create two new DiffServ instances. Se the value to CreateAndGo (4).
  4. Use the agentDiffServClassName in the agentDiffServClassTable to name the first DiffServ classifier “class_voip” and the second classifier “class_ef.”
  5. Use the agentDiffServClassType in the agentDiffServClassTable to set the class type for each classifier to All (1).
  6. Use the agentDiffServClassRuleMatchEntryType in the agentDiffServClassRuleTable to set class_voip to match a protocol (9) and class_ef to match an IP DSCP value (6).
  7. For class_voip, define a single match criterion to detect UDP packets by setting the agentDiffServClassRuleMatchProtocolNum in the agentDiffServClassRuleTable to 17.
  8. Use the agentDiffServClassRuleMatchIpDscp object in the agentDiffServClassRuleTable to define a single match criterion to detect a DSCP of EF (46). This handles incoming traffic that was previously marked as expedited elsewhere in the network.
  9. Use the agentDiffServPolicyRowStatus object in the agentDiffServPolicyTable to create a DiffServ policy. Set the value to CreateAndGo (4).
  10. Use the agentDiffServPolicyType object to set the policy direction so that it applies to inbound (1) traffic.
  11. Use the agentDiffServPolicyName object to name the new DiffServ instance “pol_voip.”
  12. Use the agentDiffServPolicyInstRowStatus object in the agentDiffServPolicyInstTable to create new instances that will be associated with the previously created classes (class_ef and class_voip).
  13. Use the agentDiffServPolicyInstClassIndex object to associate class_ef and class_voip with the policy instances.
  14. Use the agentDiffServPolicyAttrRowStatus object in the agentDiffServPolicyAttrTable to create three instances.
  15. Use the agentDiffServPolicyAttrStmtAssignQueueId to set the queue value for instances 1.1.1 and 1.2.2 to 5. so that matching packets are assigned internally to use queue 5 of the egress port to which they are forwarded.
  16. Use the agentDiffServPolicyAttrStmtMarkIpDscpVal object to set the value of instance 1.2.1 to 46, which marks UDP packets (per the class_voip definition) with a DSCP value of EF.
  17. Create an instance for the interface that will have the policy attached by using the agentDiffServServiceRowStatus object in the agentDiffServServiceTable. For example, to create an instance for interface 1/0/2, set 2.1 to CreateAndG0 (4).
  18. Attach the policy to the interface instance by using the agentDiffServServicePolicyIndex object. Set the value of the instance to 1.