H3C S5500-SI Series User manual

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Table of Contents
i
Table of Contents
Chapter 1 IGMP Snooping Configuration...................................................................................1-1
1.1 IGMP Snooping Overview .................................................................................................1-1
1.1.1 Principle of IGMP Snooping....................................................................................1-1
1.1.2 Basic Concepts in IGMP Snooping.........................................................................1-2
1.1.3 Work Mechanism of IGMP Snooping...................................................................... 1-3
1.2 IGMP Snooping Configuration Tasks................................................................................1-5
1.3 Configuring Basic Functions of IGMP Snooping ...............................................................1-6
1.3.1 Configuration Prerequisites.....................................................................................1-6
1.3.2 Enabling IGMP Snooping........................................................................................1-6
1.3.3 Configuring the Version of IGMP Snooping............................................................1-7
1.3.4 Configuring Port Aging Timers................................................................................1-8
1.4 Configuring Port Functions................................................................................................ 1-9
1.4.1 Configuration Prerequisites.....................................................................................1-9
1.4.2 Configuring Static Ports ..........................................................................................1-9
1.4.3 Enabling the Function of Simulating Member Hosts............................................. 1-10
1.4.4 Enabling the Fast Leave Feature..........................................................................1-11
1.4.5 Configuring IGMP Report Suppression.................................................................1-12
1.5 Configuring IGMP-Related Functions.............................................................................. 1-13
1.5.1 Configuration Prerequisites...................................................................................1-13
1.5.2 Enabling IGMP Snooping Querier.........................................................................1-13
1.5.3 Configuring IGMP Timers...................................................................................... 1-14
1.5.4 Configuring Source IP Address of IGMP Queries.................................................1-15
1.5.5 Configuring the Function of Dropping Unknown Multicast Data...........................1-16
1.6 Configuring a Multicast Group Policy...............................................................................1-16
1.6.1 Configuration Prerequisites...................................................................................1-16
1.6.2 Configuring a Multicast Group Filter......................................................................1-16
1.6.3 Configuring Multicast Source Port Filtering........................................................... 1-17
1.6.4 Configuring Maximum Multicast Groups that Can Pass Ports..............................1-18
1.6.5 Configuring Multicast Group Replacement...........................................................1-19
1.7 Displaying and Maintaining IGMP Snooping...................................................................1-20
1.8 IGMP Snooping Configuration Examples........................................................................ 1-21
1.8.1 Simulating Member Hosts.....................................................................................1-21
1.8.2 Static Router Port Configuration ........................................................................... 1-23
1.9 Troubleshooting IGMP Snooping Configuration.............................................................. 1-25
1.9.1 Switch Fails in Layer 2 Multicast Forwarding........................................................ 1-25
1.9.2 Configured Multicast Group Policy Fails to Take Effect........................................1-25

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Table of Contents
ii
Chapter 2 MLD Snooping Configuration.....................................................................................2-1
2.1 MLD Snooping Overview...................................................................................................2-1
2.1.1 How MLD Snooping Works..................................................................................... 2-1
2.1.2 Basic Concepts in MLD Snooping...........................................................................2-2
2.1.3 Work Mechanism of MLD Snooping .......................................................................2-3
2.2 MLD Snooping Configuration Tasks.................................................................................. 2-5
2.3 Configuring Basic Functions of MLD Snooping.................................................................2-6
2.3.1 Configuration Prerequisites.....................................................................................2-6
2.3.2 Enabling MLD Snooping .........................................................................................2-6
2.3.3 Configuring Port Aging Timers................................................................................2-7
2.4 Configuring Port Functions................................................................................................ 2-8
2.4.1 Configuration Prerequisites.....................................................................................2-8
2.4.2 Configuring Static Ports ..........................................................................................2-8
2.4.3 Enabling the Function of Simulating Member Hosts............................................... 2-9
2.4.4 Configuring the Fast Leave Feature .....................................................................2-10
2.4.5 Configuring MLD Report Suppression .................................................................. 2-11
2.5 Configuring MLD-Related Functions................................................................................2-11
2.5.1 Configuration Prerequisites...................................................................................2-11
2.5.2 Enabling MLD Snooping Querier..........................................................................2-12
2.5.3 Configuring MLD Timers.......................................................................................2-12
2.5.4 Configuring Source IPv6 Addresses of MLD Queries...........................................2-14
2.5.5 Configuring the Function of Dropping Unknown IPv6 Multicast Data................... 2-14
2.6 Configuring an IPv6 Multicast Group Policy....................................................................2-15
2.6.1 Configuration Prerequisites...................................................................................2-15
2.6.2 Configuring an IPv6 Multicast Group Filter...........................................................2-15
2.6.3 Configuring IPv6 Multicast Source Port Filtering ..................................................2-16
2.6.4 Configuring Maximum Multicast Groups that Can Pass Ports..............................2-17
2.6.5 Configuring IPv6 Multicast Group Replacement...................................................2-18
2.7 Displaying and Maintaining MLD Snooping.....................................................................2-19
2.8 MLD Snooping Configuration Examples..........................................................................2-20
2.8.1 Simulated Host Joining .........................................................................................2-20
2.8.2 Static Router Port Configuration ........................................................................... 2-22
2.9 Troubleshooting MLD Snooping......................................................................................2-23
2.9.1 Switch Fails in Layer 2 Multicast Forwarding........................................................ 2-23
2.9.2 Configured IPv6 Multicast Group Policy Fails to Take Effect ...............................2-24
Chapter 3 Multicast VLAN Configuration.................................................................................... 3-1
3.1 Introduction to Multicast VLAN ..........................................................................................3-1
3.2 Configuring Multicast VLAN...............................................................................................3-1
3.3 Displaying and Maintaining Multicast VLAN...................................................................... 3-2
3.4 Multicast VLAN Configuration Example.............................................................................3-2

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-1
Chapter 1 IGMP Snooping Configuration
When configuration IGMP Snooping, go to the following sections for information you
are interested in:
zIGMP Snooping Overview
zConfiguring Basic Functions of IGMP Snooping
zConfiguring Port Functions
zConfiguring IGMP-Related Functions
zConfiguring a Multicast Group Policy
zDisplaying and Maintaining IGMP Snooping
zIGMP Snooping Configuration Examples
zTroubleshooting IGMP Snooping Configuration
1.1 IGMP Snooping Overview
Internet Group Management Protocol Snooping (IGMP Snooping) is a multicast
constraining mechanism that runs on Layer 2 devices to manage and control multicast
groups.
1.1.1 Principle of IGMP Snooping
By analyzing received IGMP messages, a Layer 2 device running IGMP Snooping
establishes mappings between ports and MAC multicast groups andforwards multicast
data based on these mappings.
As shown in Figure 1-1, when IGMP Snooping is not running, multicast packets are
broadcast to all devices at Layer 2. When IGMP Snooping runs, multicast packets for
known multicast groups are multicast to the receivers at Layer 2.

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-2
Source
HostA
Layer 2Ethernet
Switch
HostB Receiver
HostC
Multicast
Router
Multicastpackettransmission
without IGMP Snooping Multicast packe when IGMP Sn
ttransmission
ooping runs
Multicast Packets
Source
HostA Receiver
HostC
Multicast
Router
Layer2 Ethernet
Switch
Receiver Receiver HostB
Figure 1-1 Multicast forwarding before and after IGMP Snooping runs
1.1.2 Basic Concepts in IGMP Snooping
I. IGMP Snooping related ports
As shown in Figure 1-2, Router A connects to the multicast source, IGMP Snooping
runs on Switch Aand Switch B, Host Aand Host C are receiver hosts (namely, multicast
group members).
Source
RouterA SwitchA
GE1/0/1
GE1/0/1 GE1/0/2
GE1/0/2
Receiver
HostC
HostD
SwitchB
Multicast Packets
Receiver
HostA
HostB
Router Port
Member Port
GE1/0/3
Figure 1-2 IGMP Snooping related ports
Ports involved in IGMP Snooping, as shown in Figure 1-2, are described as follows:

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-3
zRouter port: On an Ethernet switch, a router port connects theswitch to a multicast
router. In the figure, GigabitEthernet1/0/1 of Switch A and GigabitEthernet1/0/1 of
Switch B are router ports. A switch registers all its local router ports in its router
port list.
zMember port: On an Ethernet switch, a member port (also known as multicast
group member port) connects the switch to a multicast group member. In the
figure, GigabitEthernet1/0/2 and GigabitEthernet1/0/3 of Switch A and
GigabitEthernet1/0/2 of Switch B are member ports. The switch records all
member ports on the local device in the IGMP Snooping forwarding table.
Note:
Whenever mentioned in this document, a router port is a router-connecting port on a
switch, rather than a port on a router.
II. Port aging timers in IGMP Snooping and related messages and actions
Table 1-1 Port aging timers in IGMP Snooping and related messages and actions
Timer Description Message before
expiry
Action after
expiry
Router
port aging
timer
For each router port, the
switch sets a timer
initialized to the aging time
of the route port
IGMP general
query or PIM hello
message of which
the source
address is not
0.0.0.0
The switch
removes this port
from its router port
list
Member
port aging
timer
When a port joins an
multicast group, the switch
sets a timer for the port,
which is initialized to the
member port aging time
IGMP report
message
The switch
removes this port
from the multicast
group forwarding
table
1.1.3 Work Mechanism of IGMP Snooping
A switch running IGMP Snooping performs different actions when it receives different
IGMP messages, as follows:
I. General queries
The IGMP querier periodically sends IGMP general queries to all hosts and routers on
the local subnet to find out whether multicast group members exist on the subnet.
Upon receiving an IGMP general query, the switch forwards it through all ports in the
VLAN except the receiving port and performs the following to the receiving port:

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-4
zIf the receiving port is a router port existing in its router port list, the switch resets
the aging timer of this router port.
zIf the receiving port is not a router port existing in its router port list, the switch adds
it into its router port list and sets an aging timer for this router port.
II. Membership reports
A host sends an IGMP report to the multicast router in the following circumstances:
zUpon receiving an IGMP query, a multicast group member host responds with an
IGMP report.
zWhen intended to join a multicast group, a host sends an IGMP report to the
multicast router to announce that it is to join the multicast group.
Upon receiving the IGMPreport, the switch forwards it throughall the router ports in the
VLAN and performs the following to the receiving port:
zResolves the address of the multicast group that the host is to join and add a
forwarding entry for this port in the forwarding table.
zSets or resets a member port aging timer for this port.
Note:
A switch will not forward an IGMP report through a non-router port for the following
reason: When IGMP report suppression is enabled, if member hosts of that multicast
group still exist under non-router ports, the hosts will stop sending reports when they
receive the message, and this prevents the switch from knowing if members of that
multicast group are still attached to these ports.
III. Leave messages
When an IGMPv1 host leaves a multicast group, the host does not send an IGMPleave
message, so the switch cannot know immediately that the host has left the multicast
group. However, as the host stops sending IGMP reports as soon as it leaves a
multicast group, the switch deletes the forwarding entry for the member port
corresponding to the host from the forwarding table when its aging timer expires.
When an IGMPv2 or IGMPv3 host leaves a multicast group, the host sends an IGMP
leave message to the multicast router to announce that it has leaf the multicast group.
Upon receiving an IGMP leave message on the last member port, a switch forwards it
out all router ports in the VLAN. Because the switch does not know whether any other
member hosts of that multicast group still exists under the port to which the IGMPleave
message arrived, the switch does not immediately delete the forwarding entry
corresponding to that port from the forwarding table; instead, it resets the aging timer of
the member port.

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-5
Upon receiving the IGMP leave message from a host, the IGMP querier resolves from
the message the address of the multicast group that the host just left and sends an
IGMP group-specific query to that multicast group through the port that received the
leave message. Upon receiving the IGMP group-specific query, a switch forwards it
through all the router ports in the VLAN and all member ports of that multicast group,
and performs the following to the receiving port:
zIf a response to an IGMP report from that multicast group arrives to the member
port before its aging timer expires, this means that some other members of that
multicast group still exist under that port: the switch resets the aging timer of the
member port.
zIf no IGMP report from that multicast group arrives to this member port before its
aging timer expires as a response to the IGMP group-specific query,this means
that no members of that multicast group still exist under the port: the switch
deletes the forwarding entry corresponding to the port from the forwarding table
when the aging timer expires.
1.2 IGMP Snooping Configuration Tasks
Complete these tasks to configure IGMP Snooping:
Task Remarks
Enabling IGMP Snooping Required
Conf
Siguring the Version of IGMP nooping Optional
Configuring Basic
Functions of IGMP
Snooping Configuring Port Aging Timers Optional
Configuring Static Ports Optional
Enabling the Function of Simulating
er Hosts
Memb Optional
Enabling the Fast Leave Feature Optional
Configuring Port
Functions
Configuring IGMP Report
Suppression Optional
Enabling IGMP Snooping Querier Optional
Configuring IGMP Timers Optional
Configuring Source IP Address of
IGMP Queries Optional
Configuring
IGMP-Related
Functions
Configuring the Function of
Dropping Unknown Multicast Data Optional

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-6
Task Remarks
Configuring a Multicast Group Filter Optional
Configuring Multicast Source Port
Filtering Optional
Configuring Maximum Multicast
Groups that Can Pass Ports Optional
Configuring a Multicast
Group Policy
Configuring Multicast Group
Replacement Optional
Note:
zConfigurations performed in IGMP Snooping view are effective for all VLANs, while
configurations made in VLAN view are effective only for ports belonging to the
current VLAN. Configurations made in VLAN view override the corresponding
configurations made in IGMP Snooping view.
zConfigurations performed in IGMP Snooping view are globally effective;
configurations performed in port view are effective only for the current port;
configurations performed in port group view are effective only for all the ports in the
current port group.
zThe system gives priority to configurations made in port view or port group view.
Configurations made in IGMP Snooping view are used only if the corresponding
configurations have not been carried out in port view or port group view.
1.3 Configuring Basic Functions of IGMP Snooping
1.3.1 Configuration Prerequisites
Before configuring the basic functions of IGMP Snooping, complete the following tasks:
zConfigure the corresponding VLANs
zConfigure the corresponding port groups
Before configuring the basic functions of IGMP Snooping, prepare the following data:
zVersion of IGMP Snooping
zAging time of router ports
zAging timer of member ports
1.3.2 Enabling IGMP Snooping
Follow these steps to enabling IGMP Snooping:

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-7
To do... Use the command... Remarks
Enter system view system-view —
Enable IGMP Snooping
globally and enter IGMP
Snooping view igmp-snooping Required
Disabled by default
Return to system view quit —
Enter VLAN view vlan vlan-id —
Enable IGMP Snooping in
the VLAN igmp-snooping enable Required
Disabled by default
Note:
zIGMP Snooping must be enabled globally before it can be enabled in a VLAN.
zIf you enable IGMP Snooping in a specified VLAN, this function takes effect for
Ethernet ports in this VLAN only.
1.3.3 Configuring the Version of IGMP Snooping
By configuring the IGMP Snooping version, you are actually configuring the version of
IGMP messages that can be analyzed and processed by IGMP Snooping.
zIn the case of version 2, IGMP Snooping can analyze and process IGMPv1 and
IGMPv2 messages, but not IGMPv3 messages, which will be broadcast in the
VLAN.
zIf the current is 3, IGMP Snooping can analyze and process IGMPv1, IGMPv2 and
IGMPv3 messages.
Follow these steps to configure the version of IGMP Snooping:
To do... Use the command... Remarks
Enter system view system-view —
Enter VLAN view vlan vlan-id —
Configure the version of
IGMP Snooping igmp-snooping version
version-number
Optional
Version 2 by default

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-8
Caution:
If you switch IGMP Snooping from version 3 to version 2, the system will:
zKeep forwarding entries for version 3 static (*, G) joins;
zClear forwarding entries for version 3 static (S, G) joins, which will be restored when
IGMP Snooping is switched back to version 3.
1.3.4 Configuring Port Aging Timers
If the switch does not receive an IGMP general query or a PIM hello message before
the aging timer of a router port expires, the switch deletes this port from the router port
list when the aging timer times out.
If the switch does not receive an IGMP report from a multicast group before the aging
timer of a member port expires, the switch deletes this port from the forwarding table for
that multicast group when the aging timers times out.
If multicast group memberships change frequently, you can set a relatively small value
for the member port aging timer, and vice versa.
I. Configuring port aging timers globally
Follow these steps to configure port aging timers globally:
To do... Use the command... Remarks
Enter system view system-view —
Enter IGMP Snooping
view igmp-snooping —
Configure router port
aging time
router-aging-time
interval
Optional
105 seconds by default
Configure member port
aging time host-aging-time interval Optional
260 seconds by default
II. Configuring port aging timers in a VLAN
Follow these steps to configure port aging timers in a VLAN:
To do... Use the command... Remarks
Enter system view system-view —
Enter VLAN view vlan vlan-id —

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-9
To do... Use the command... Remarks
Configure router port
aging time
igmp-snooping
router-aging-time
interval
Optional
105 seconds by default
Configure member port
aging time
igmp-snooping
host-aging-time interval
Optional
260 seconds by default
1.4 Configuring Port Functions
1.4.1 Configuration Prerequisites
Before configuring port functions, complete the following task:
zEnable IGMP Snooping in the VLAN
Before configuring port functions, prepare the following data:
zMulticast group and multicast source addresses
zWhether to enable the fast leave feature
zWhether to enabled IGMP report suppression
1.4.2 Configuring Static Ports
If the host attached to a port needs to receive multicast data addressed to a particular
multicast group or from a particular multicast source/group, you can configure this port
to be a static member port of that multicast group or multicast source/group.
In a network with a stable topology structure, you can configure router ports of a switch
into static router ports, through which the switch can receive IGMP messages from
routers.
Follow these steps to configure static ports:
To do... Use the command... Remarks
Enter system view system-view —
Enter
Ethernet
port view
interface interface-type
interface-number
Enter
the
corre
spon
ding
view
Enter port
group view
port-group { manual port-group-name
| aggregation agg-id }
Use either
command
Configure a static
member port
igmp-snooping static-group
group-address [ source-ip
source_address ] vlan vlan-id
Required
Disabled by default
Configuring a static
router port
igmp-snooping static-router-port
vlan vlan-id
Required
Disabled by default

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-10
Note:
zThe function of static joining to a multicast source/group is available only if a valid
multicast source address is specified and IGMP Snooping version 3 is currently
running.
zWhen you configure or remove a port as a static member port of a multicast group or
multicast source/group, the port will not initiate an IGMP report or an IGMP leave
message.
zStatic member ports andstatic router ports never age out. To delete such aport, you
need to use the corresponding command.
1.4.3 Enabling the Function of Simulating Member Hosts
Generally, a host running IGMP responds to IGMP queries from a multicast router. If a
host fails to respond due to some reasons, the multicast router will deem that no
member of this multicast group exists on the network segment, and therefore will
remove the corresponding forwarding path.
To avoid this situation from happening, you can configure a port of the switch as a
member of the multicast group(namely, enable the function of simulating member hosts
on the port). When an IGMP query arrives, that member port will give a response. As a
result, the switch can continue receive multicast data.
Through this configuration, the following functions can be implemented:
zWhen the function of simulating member hosts is enabled on an Ethernet port, the
simulated host sends an IGMP report.
zWhen receiving an IGMP general query, the simulated host responds with an
IGMP report just like a real host.
zWhen the function of simulating member hosts is disabled on an Ether port, the
simulated host sends an IGMP leave message.
Follow these steps to enable the function of simulating member hosts:
To do... Use the command... Remarks
Enter system view system-view —
Enter
Ethernet
port view
interface interface-type
interface-number
Enter
the
corre
spon
ding
view
Enter port
group view
port-group { manual
port-group-name | aggregation
agg-id }
Use either
command

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-11
To do... Use the command... Remarks
Enable the function
of simulating a
member host of a
multicast group or
multicast
source/group
igmp-snooping host-join
group-address [ source-ip
source-address ] vlan vlan-id
Required
Disabled by
default
Note:
zEach simulated host is equivalent to an independent host. For example, when
receiving an IGMP query, the simulated host corresponding to each configuration
responds respectively.
zThe IGMP version of the simulated host is the same as the IGMP Snooping version
current running on the device.
1.4.4 Enabling the Fast Leave Feature
By default, when receiving a group-specific IGMP leave message on a port, the switch
first sends an IGMP group-specific query message that port, rather than directly
deleting the port from the multicast forwarding table. If the switch receives no response
within a certain period of waiting time, it deletes the port from the forwarding table.
With the fast leave feature enabled, when the switch receives a group-specific IGMP
leave message on a port, the switch directly deletes this port from the forwarding table
without first sending an IGMP group-specific query to the port.
I. Configuring the fast leave feature globally
Follow these steps to configure the fast leave feature globally:
To do... Use the command... Remarks
Enter system view system-view —
Enter IGMP Snooping
view igmp-snooping —
Enable the fast leave
feature fast-leave [vlan vlan-list ] Required
Disabled by default
II. Configuring the fast leave feature on a port or a group ports
Follow these steps to configure the fast leave feature on a port or a group ports:

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-12
To do... Use the command... Remarks
Enter system view system-view —
Enter Ethernet
port view
interface interface-type
interface-number
Enter
the
corre
spon
ding
view
Enter port
group view
port-group { manual
port-group-name | aggregation
agg-id }
Use either
command
Enable the fast leave
feature
igmp-snooping fast-leave [vlan
vlan-list ]
Required
Disabled by default
Caution:
If the fast leave feature is enabled on a port to which more than one host is connected,
when one host leaves a multicast group, the other hosts connected to port and
interested in the same multicast group will fail to receive multicast data for that group.
1.4.5 Configuring IGMP Report Suppression
When a Layer 2 device receives an IGMP report from a multicast group member, the
device forwards the message to the Layer 3 device directly connected with it. Thus,
when multiple members belonging to a multicast group exit on the Layer 2 device, the
Layer 3 device directly connected with it will receive duplicate IGMP reports from these
members.
With the IGMP report suppression function enabled, within a query interval, the Layer 2
device forwards only the first IGMPreport of a multicast group to the Layer 3 device and
will not forward the subsequent IGMP reports from the same multicast group to the
Layer 3 device. This helps reduce the number of packets being transmitted over the
network.
Follow these steps to configure IGMP report suppression:
To do... Use the command... Remarks
Enter system view system-view —
Enter IGMP Snooping
view igmp-snooping —
Enable IGMP report
suppression report-aggregation Optional
Enabled by default

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-13
1.5 Configuring IGMP-Related Functions
1.5.1 Configuration Prerequisites
Before configuring IGMP-related functions, complete the following task:
zEnable IGMP Snooping in the VLAN
Before configuring IGMP-related functions, prepare the following data:
zIGMP general query interval
zIGMP last-member query interval
zMaximum response time to IGMP general queries
zSource address of IGMP general queries
zSource address of IGMP group-specific queries
zWhether to enable the function of dropping unknown multicast data
1.5.2 Enabling IGMP Snooping Querier
In an IP multicast network running IGMP, a Layer 3 multicast device acts as the IGMP
querier, responsible for sending IGMP queries.
In a network that does not comprise Layer 3 multicast devices, however, it is a problem
to implement an IGMP querier, because Layer 2 device do not support IGMP. To solve
this problem, you can enable the IGMP Snooping querier function on a Layer 2 device
so that it can work as an IGMP querier to create and maintain multicast forwarding
entries at the data link layer.
Follow these steps to enable IGMP Snooping querier:
To do... Use the command... Remarks
Enter system view system-view —
Enter VLAN view vlan vlan-id —
Enable IGMP Snooping
querier igmp-snooping querier Required
Disabled by default
Caution:
zThe IGMP Snooping querier does not take part in IGMP querier elections.
zIt is meaningless to configure an IGMP Snooping querier in a multicast network
running IGMP. Furthermore, it may affect IGMP querier elections because it sends
IGMP general queries that contain low source IP addresses.

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-14
1.5.3 Configuring IGMP Timers
You can tune the IGMP general query interval based on actual condition of the network.
Upon receiving an IGMP query (general query or group-specific query), a host starts a
timers for each multicast group it has joined. This timer is initialized to a random value
in the range of 0 to the maximum response time (the host obtains the value of the
maximum response time from the Max Response Time field in the IGMP query it
received). When the timer value comes down to 0, the host sends an IGMP report to the
corresponding multicast group.
An appropriate setting of the maximum response time for IGMP queries allows hosts to
respond to queries quickly and avoids burstiness of IGMP traffic on the network caused
by reports simultaneously sent by a large number of hosts when corresponding timers
expires simultaneously.
zFor IGMP general queries, you can configure the maximum response time to fill
their Max Response time field.
zFor IGMP group-specific queries, you can configure the IGMP last-member query
interval to fill their Max Response time field. Namely, for IGMP group-specific
queries, the maximum response time equals to the IGMP last-member query
interval.
I. Configuring IGMP timers globally
Follow these steps to configure IGMP timers globally:
To do... Use the command... Remarks
Enter system view system-view —
Enter IGMP Snooping
view igmp-snooping —
Configure the maximum
response time to IGMP
general queries
max-response-time
interval
Optional
10 seconds by default
Configure the IGMP
last-member query
interval
last-member-query-inte
rval interval
Optional
1 second by default
II. Configuring IGMP timers in a VLAN
Follow these steps to configure IGMP timers in a VLAN:
To do... Use the command... Remarks
Enter system view system-view —
Enter VLAN view vlan vlan-id —

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-15
To do... Use the command... Remarks
Configure IGMP general
query interval
igmp-snooping
query-interval interval
Optional
60 second by default
Configure the maximum
response time to IGMP
general queries
igmp-snooping
max-response-time
interval
Optional
10 seconds by default
Configure the IGMP
last-member query
interval
igmp-snooping
last-member-query-inte
rval interval
Optional
1 second by default
Caution:
In the configuration, make sure that the IGMP general query interval is larger than the
maximum response time for IGMP general queries.
1.5.4 Configuring Source IP Address of IGMP Queries
Upon receiving an IGMPquery whose source IP address is 0.0.0.0 on a port, the switch
will not set that port as a router port. Therefore, we recommend that you configure a
valid IP address as the source IP address of IGMP queries.
Follow these steps to configure source IP address of IGMP queries:
To do... Use the command... Remarks
Enter system view system-view —
Enter VLAN view vlan vlan-id —
Configure the source
address of IGMP general
queries
igmp-snooping general-query
source-ip { current-interface |
ip-address }
Optional
0.0.0.0 by
default
Configure the source IP
address of IGMP
group-specific queries
igmp-snooping special-query
source-ip { current-interface |
ip-address }
Optional
0.0.0.0 by
default
Caution:
The source address of IGMPquery messages may affect IGMP querier selection within
the segment.

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-16
1.5.5 Configuring the Function of Dropping Unknown Multicast Data
Unknown multicast data refers to multicast data whose forwarding entries do not exist
in the corresponding multicast forwarding table.
Follow these steps to configure the function of dropping unknown multicast data in a
VLAN:
To do... Use the command... Remarks
Enter system view system-view —
Enter VLAN view vlan vlan-id —
Enable the function of
dropping unknown
multicast data
igmp-snooping
drop-unknown
Required
Disabled by default
Note:
When enabled to drop unknown IPv4 multicast data, are automatically enabled to drop
unknown IPv6 multicast data.
1.6 Configuring a Multicast Group Policy
1.6.1 Configuration Prerequisites
Before configuring a multicast group filtering policy, complete the following task:
zEnable IGMP Snooping in the VLAN or enable IGMP on the desired VLAN
interface
Before configuring a multicast group filtering policy, prepare the following data:
zACL rule for multicast group filtering
zWhether to enable multicast source port filtering
zThe maximum number of multicast groups that can pass the ports
zWhether to enable multicast group replacement
1.6.2 Configuring a Multicast Group Filter
On an IGMP Snooping–enabled switch, the configuration of a multicast group allows
the service provider to define limits of multicast programs available to different users.
In actual application, when a user requests a multicast program, the user’s host
initiates an IGMP report. After the message reaches the switch, the switch checks the
report against the ACL rule configured on the receiving port. If the receiving port can
join this multicast group, the switch adds this port to the IGMP Snooping multicast

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-17
group list; otherwise the switch drops this report message. Thus, the multicast data will
not be sent to this port. In this way, the service provider can control the VOD programs
provided for multicast users.
I. Configuring a multicast group filter globally
Follow these steps to configure a multicast group filter globally:
To do... Use the command... Remarks
Enter system view system-view —
Enter IGMP Snooping
view igmp-snooping —
Configure a multicast
group filter
group-policy acl-number
[vlan vlan-list ]
Required
No filter configured by
default
II. Configuring a multicast group filter on a port or a group ports
Follow these steps to configuring a multicast group filter on a port or a group ports:
To do... Use the command... Remarks
Enter system view system-view —
Enter
Ethernet
port view
interface interface-type
interface-number
Enter
the
corre
spon
ding
view
Enter port
group
view
port-group { manual port-group-name
| aggregation agg-id }
Use either
command
Configure a
multicast group
filter
igmp-snooping group-policy
acl-number [ vlan vlan-list ]
Required
No filter configured
by default
1.6.3 Configuring Multicast Source Port Filtering
With the multicast source port filtering feature enabled, you can enable ordisable a port
as a multicast source port.
zIf this feature is enabled on a port, the port can be connected with multicast
receivers only rather than with multicast sources, because the port will block all
multicast data packets while it permits multicast protocol packets to pass.
zIf this feature is disabled on a port, the port can be connected with both multicast
sources and multicast receivers.

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches Chapter 1 IGMP Snooping Configuration
1-18
I. Configuring multicast source port filtering globally
Follow these steps to configure multicast source port filtering globally:
To do... Use the command... Remarks
Enter system view system-view —
Enter IGMP Snooping
view igmp-snooping —
Enable multicast source
port filtering source-deny port interface-list Required
Disabled by default
II. Configuring multicast source port filtering on a port or a group ports
Follow these steps to configure multicast source port filtering on a port or a group ports:
To do... Use the command... Remarks
Enter system view system-view —
Enter Ethernet
port view
interface interface-type
interface-number
Enter
the
corre
spon
ding
view
Enter port
group view
port-group { manual
port-group-name | aggregation
agg-id }
Use either command
Enable multicast source
port filtering igmp-snooping source-deny Required
Disabled by default
Note:
When enabled to filter IPv4 multicast data based on the source ports, are automatically
enabled to filter IPv6 multicast data based on the source ports.
1.6.4 Configuring Maximum Multicast Groups that Can Pass Ports
By configuring the maximum number of multicast groups that can pass a port or a group
of ports, you can limit the number of number of multicast programs on-demand
available to users, thus to control the traffic on the port.
Follow these steps to configure the maximum number of multicast groups that can pass
the port(s):
To do... Use the command... Remarks
Enter system view system-view —