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.
IGMP and MLD Snooping Switches
A snooping switch can be configured to receive
IGMP (Internet Group Management Protocol)
packets in
a subnet and identify ports on which interested IP multicast listeners are present. It also identifies the
ports on which multicast routers are attached, and these are the likely ports on which IP multicast
sources are present. This section describes how the snooping switch handles IGMP messages, addresses
considerations for IGMP packet and IP multicast traffic forwarding, and provides information about
support for IGMP and MLD versions.
Query Processing
When a port receives an
query, the snooping switch identifies the receiving port as a multicast
router-attached port. The switch maintains the list of multicast router-attached ports on a per-VLAN
basis. If the port does not receive periodic IGMP queries, the learned entries maintained in the list expire
after a configured interval. The snooping switch stores the last received query on a VLAN because the
switch uses this to calculate the max response time value during IGMP Leave message processing.
The snooping switch treats Distance Vector Multicast Routing Protocol (DVMRP) probe messages and
Protocol Independent Multicast (PIM) versions 1 and 2 hello messages that it receives similar to IGMP
queries by adding the interfaces that receive these messages to the list of multicast router-attached
ports.
Group Registration
Multicast listeners can register to an IP multicast group by sending an
Report message in
response to a general query from a multicast router or by sending an unsolicited IGMP Report message.
When the snooping switch processes an IGMP Report message, it creates an entry in the Layer 2
Configuration Examples
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