xStack® DES-3528/DES-3552 Series Layer 2 Managed Stackable Fast Ethernet Switch Web UI Reference Guide
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Figure 3 - 2 CPU Filter L3 Control Packet Settings window
The following fields can be set:
Parameter Description
Unit
Select a unit to be configured.
From Port / To Port
Check the corresponding boxes for the port(s) to filter control packets.
State
Use the drop-down menu to enable or disable the filtering function.
IGMP Query
Tick the check box to set IGMP query packets as the control packets.
DVMRP
Tick the check box to set DVMRP query packets as the control packets.
PIM
Tick the check box to set PIM query packets as the control packets.
All
Tick the check box to set all above query packets as the control packets.
To enable the function, enter the information and click Apply.
MLD Snooping
Multicast Listener Discovery (MLD) Snooping is an IPv6 function used similarly to IGMP snooping in IPv4. It is used
to discover ports on a VLAN that are requesting multicast data. Instead of flooding all ports on a selected VLAN
with multicast traffic, MLD snooping will only forward multicast data to ports that wish to receive this data through
the use of queries and reports produced by the requesting ports and the source of the multicast traffic.
MLD snooping is accomplished through the examination of the layer 3 part of an MLD control packet transferred
between end nodes and a MLD router. When the Switch discovers that this route is requesting multicast traffic, it
adds the port directly attached to it into the correct IPv6 multicast table, and begins the process of forwarding
multicast traffic to that port. This entry in the multicast routing table records the port, the VLAN ID, and the
associated multicast IPv6 multicast group address, and then considers this port to be an active listening port. The
active listening ports are the only ones to receive multicast group data.
MLD Control Messages
Three types of messages are transferred between devices using MLD snooping. These three messages are all
defined by four ICMPv6 packet headers, labeled 130, 131, 132, and 143.
1. Multicast Listener Query – Similar to the IGMPv2 Host Membership Query for IPv4, and labeled as 130 in
the ICMPv6 packet header, this message is sent by the router to ask if any link is requesting multicast data.
There are two types of MLD query messages emitted by the router. The General Query is used to advertise
all multicast addresses that are ready to send multicast data to all listening ports, and the Multicast Specific
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