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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:

Enable IGMP Snooping in the VLAN

Before configuring IGMP-related functions, prepare the following data:

IGMP general query interval

IGMP last-member query interval

Maximum response time to IGMP general queries

Source address of IGMP general queries

Source address of IGMP group-specific queries

Whether 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:

The IGMP Snooping querier does not take part in IGMP querier elections.

It 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.

Summary of Contents for S5500-SI Series

Page 1: ...nfiguring 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 Prerequ...

Page 2: ...rier 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 Configuri...

Page 3: ...ration Examples z Troubleshooting 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 ...

Page 4: ...eiver 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 A and Switch B Host A and 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...

Page 5: ...ons 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 Mem...

Page 6: ...n 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 h...

Page 7: ... 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 tas...

Page 8: ...ally 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 z The 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...

Page 9: ...nction 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 z In the case of version 2 IGMP Snooping can analyze and process IGMPv1 and IGMPv2 messages but not IGMPv3 messages which will be broadcast in th...

Page 10: ...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 ...

Page 11: ...ttached 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 mes...

Page 12: ...re 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 functio...

Page 13: ... 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 d...

Page 14: ...g 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 suppressio...

Page 15: ...s 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 ...

Page 16: ...by reports simultaneously sent by a large number of hosts when corresponding timers expires simultaneously z For IGMP general queries you can configure the maximum response time to fill their Max Response time field z For 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 respons...

Page 17: ...eries 1 5 4 Configuring Source IP Address of IGMP Queries Upon receiving an IGMP query 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 s...

Page 18: ...es Before configuring a multicast group filtering policy complete the following task z Enable IGMP Snooping in the VLAN or enable IGMP on the desired VLAN interface Before configuring a multicast group filtering policy prepare the following data z ACL rule for multicast group filtering z Whether to enable multicast source port filtering z The maximum number of multicast groups that can pass the po...

Page 19: ...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 N...

Page 20: ... 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 mult...

Page 21: ...ystem deletes this port from all the related IGMP Snooping forwarding entries and applies the new configurations until the number of multicast groups the port has joined reaches the maximum number configured 1 6 5 Configuring Multicast Group Replacement For some special reasons the number of multicast groups passing through a switch or Ethernet port may exceed the number configured for the switch ...

Page 22: ...w Enter port group view port group manual port group name aggregation agg id Use either command Configure multicast group replacement igmp snooping overflow replace vlan vlan list Required Disabled by default 1 7 Displaying and Maintaining IGMP Snooping To do Use the command Remarks View the information of multicast groups learned by IGMP Snooping display igmp snooping group vlan vlan id verbose A...

Page 23: ... I Network requirements After the configuration Host A and Host B regardless of whether they have joined the multicast group 224 1 1 1 can receive multicast data that the multicast source 1 1 1 1 24 sends to the multicast group 224 1 1 1 Figure 1 3 shows the network connections II Network diagram Source Multicast Packets HostA SwitchA RouterA HostB Receiver GE1 0 1 GE1 0 2 1 1 1 1 24 Receiver Host...

Page 24: ...terface GigabitEthernet1 0 3 SwitchA GigabitEthernet1 0 3 igmp snooping host join 224 1 1 1 source ip 1 1 1 1 vlan 100 SwitchA GigabitEthernet1 0 3 quit SwitchA interface GigabitEthernet 1 0 4 SwitchA GigabitEthernet 1 0 4 igmp snooping host join 224 1 1 1 source ip 1 1 1 1 vlan 100 SwitchA GigabitEthernet 1 0 4 quit 3 Verifying the configuration View the detailed information of the multicast grou...

Page 25: ... 1 1 8 2 Static Router Port Configuration I Network requirements No multicast protocol is running on Router B After the configuration Switch A should be able to forward multicast data to Router B Figure 1 4 shows the routernetwork connections II Network diagram Source Multicast Packets HostA Switc RouterA RouterB HostB hA Receiver 0 3 GE1 0 1 GE1 0 2 GE1 GE1 0 4 1 1 1 1 24 Internet Figure 1 4 Netw...

Page 26: ... configuration View the detailed information of the multicast group in VLAN 100 SwitchA display igmp snooping group vlan 100 verbose Total 1 IP Group s Total 1 IP Source s Total 1 MAC Group s Port flags D Dynamic port S Static port A Aggregation port C Copy port Subvlan flags R Real VLAN C Copy VLAN Vlan id 100 Total 1 IP Group s Total 1 IP Source s Total 1 MAC Group s Router port s total 2 port G...

Page 27: ... 1 9 2 Configured Multicast Group Policy Fails to Take Effect I Symptom Although a multicast group policy has been configured to allow hosts to join specific multicast groups the hosts can still receive multicast data addressed to other multicast groups II Analysis z The ACL rule is incorrectly configured z The multicast group policy is not correctly applied z The function of dropping unknown mult...

Page 28: ... If not use the drop unknown or igmp snooping drop unknown command to enable the function of dropping unknown multicast data 4 Use the display igmp snooping group command to check whether any port has been configured as a static member port of any multicast group If so check whether this configuration conflicts with the configured multicast group policy If any conflict exists remove the port as a ...

Page 29: ...ion Examples z Troubleshooting MLD Snooping 2 1 MLD Snooping Overview Multicast Listener Discovery Snooping MLD Snooping is an IPv6 multicast constraining mechanism that runs on Layer 2 devices to manage and control IPv6 multicast groups 2 1 1 How MLD Snooping Works By analyzing received MLD messages a Layer 2 device running MLD Snooping establishes mappings between ports and MAC multicast groups ...

Page 30: ...eceiver HostB Figure 2 1 IPv6 multicast before and after MLD Snooping runs 2 1 2 Basic Concepts in MLD Snooping I MLD Snooping related ports As shown in Figure 2 2 Router A connects to the multicast source MLD Snooping runs on Switch A and Switch B Host A and Host C are receiver hosts namely IPv6 multicast group members Source RouterA SwitchA GE1 0 1 GE1 0 1 GE1 0 2 GE1 0 2 Receive HostC HostD Swi...

Page 31: ...rt aging timers in MLD 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 MLD general query or IPv6 PIM hello message of which the source address is not 0 0 The switch removes this port from its router port list Member port aging ti...

Page 32: ...owing reason When MLD report suppression is enabled if member hosts of that IPv6 multicast group still exist under other non router ports these hosts will stop sending MLD reports when they receive the message This prevents the switch from knowing if members of that IPv6 multicast group are still attached to these ports III Done messages When a host leaves an IPv6 multicast group the host sends an...

Page 33: ...its aging timer expires 2 2 MLD Snooping Configuration Tasks Complete these tasks to configure MLD Snooping Task Remarks Enabling MLD Snooping Required Configuring Basic Functions of MLD Snooping Configuring Port Aging Timers Optional Configuring Static Ports Optional Enabling the Function of Simulating Member Hosts Optional Configuring the Fast Leave Feature Optional Configuring Port Functions Co...

Page 34: ...r port group view Configurations made in MLD Snooping view are used only if the corresponding configurations have not been carried out in port view or port group view 2 3 Configuring Basic Functions of MLD Snooping 2 3 1 Configuration Prerequisites Before configuring the basic functions of MLD Snooping complete the following tasks z Configure the corresponding VLANs z Configure the corresponding p...

Page 35: ...port from the forwarding table for that IPv6 multicast group when the aging timers times out If IPv6 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 MLD...

Page 36: ... a port needs to receive IPv6 multicast data addressed to a particular IPv6 multicast group you can configure this port to be a static member port of that IPv6 multicast 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 MLD messages from routers or Layer 3 switches Follow these steps to confi...

Page 37: ...e function of simulating a member host on the port When an MLD query arrives that member port will give a response As a result the switch can continue receive IPv6 multicast data Through this configuration the following functions can be implemented z When the function of simulating member hosts is enabled on an Ethernet port the simulated host sends an MLD report z When receiving an MLD general qu...

Page 38: ...abled when the switch receives a group specific MLD done message on a port the switch directly deletes this port from the forwarding table without first sending a MLD 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 MLD Snooping view mld sn...

Page 39: ... it Thus when multiple members belonging to an IPv6 multicast group exit on the Layer 2 device the Layer 3 device directly connected with it will receive duplicate MLD reports from these members With the MLD report suppression function enabled within a query interval the Layer 2 device forwards only the first MLD report of an IPv6 group to the Layer 3 device and will not forward the subsequent MLD...

Page 40: ... it can work as an MLD querier to create and maintain IPv6 multicast forwarding entries at the data link layer Follow these steps to enable the MLD Snooping querier To do Use the command Remarks Enter system view system view Enter VLAN view vlan vlan id Enable the MLD Snooping querier mld snooping querier Required Disabled by default Caution z The MLD Snooping querier does not take part in MLD que...

Page 41: ...eld Namely for MLD group specific queries the maximum response time equals to the MLD last member query interval I Configuring MLD timers globally Follow these steps to configure MLD timers globally To do Use the command Remarks Enter system view system view Enter MLD Snooping view mld snooping Configure the maximum response time for MLD general queries max response time interval Optional 10 secon...

Page 42: ...w Enter VLAN view vlan vlan id Configure the source IPv6 address of MLD general queries mld snooping general query source ip current interface ipv6 address Optional fe80 02ff ffff fe00 0001 by default Configure the source IPv6 address of MLD group specific queries mld snooping special query source ip current interface ipv6 address Optional ffe80 02ff ffff fe00 0001 by default Caution The source IP...

Page 43: ...v6 multicast source port filtering z The maximum number of IPv6 multicast groups that can pass the ports z Whether to enable IPv6 multicast group replacement 2 6 2 Configuring an IPv6 Multicast Group Filter On a MLD Snooping enabled switch the configuration of an IPv6 multicast group filter allows the service provider to define limits of multicast programs available to different users In actual ap...

Page 44: ...id Use either command Configure an IPv6 multicast group filter mld snooping group policy acl number vlan vlan list Required No Ipv6 filter configured by default 2 6 3 Configuring IPv6 Multicast Source Port Filtering With the IPv6 multicast source port filtering feature enabled you can enable or disable a port as a multicast source port z If this feature is enabled on a port the port can be connect...

Page 45: ...t group view port group manual port group name aggregation agg id Use either command Enable IPv6 multicast source port filtering mld snooping source deny Required Disabled by default Note When enabled to filter IPv6 multicast data based on the source ports are automatically enabled to filter IPv4 multicast data based on the source ports 2 6 4 Configuring Maximum Multicast Groups that Can Pass Port...

Page 46: ...ort from all the related MLD Snooping forwarding entries and applies the new configurations until the number of IPv6 multicast groups the has joined reaches the maximum number configured 2 6 5 Configuring IPv6 Multicast Group Replacement For some special reasons the number of IPv6 multicast groups passing through a switch or Ethernet port may exceed the number configured for the switch or the port...

Page 47: ...g view Enter port group view port group manual port group name aggregation agg id Use either command Configure IPv6 multicast group replacement mld snooping overflow replace vlan vlan list Required Disabled by default 2 7 Displaying and Maintaining MLD Snooping To do Use the command Remarks View the information of IPv6 multicast groups learned by MLD Snooping display mld snooping group vlan vlan i...

Page 48: ...ng I Network requirements After the configuration Host A and Host B regardless of whether they have joined the IPv6 multicast group FF1E 1 can receive IPv6 multicast data addressed to the IPv6 multicast group FF1E 1 Figure 2 3 shows the network connections II Network diagram Source IPv6 Multicast Packets HostA SwitchA RouterA HostB Receiver GE1 0 1 GE1 0 2 Receiver HostC GE1 GE1 0 4 0 3 Figure 2 3...

Page 49: ...interface GigabitEthernet1 0 4 SwitchA GigabitEthernet1 0 4 mld snooping host join ff1e 1 vlan 100 SwitchA GigabitEthernet1 0 4 quit 3 Verifying the configuration View the detailed information of the IPv6 multicast group in VLAN 100 SwitchA display mld snooping group vlan 100 verbose Total 1 IP Group s Total 1 IP Source s Total 1 MAC Group s Port flags D Dynamic port S Static port A Aggregation po...

Page 50: ...icast data to Router B Figure 2 4 shows the routernetwork connections II Network diagram Source IPv6 Multicast Packets HostA Sw RouterA RouterB HostB itchA Receiver 1 0 3 GE1 0 1 GE1 0 2 GE GE1 0 4 Internet Figure 2 4 Network diagram for static router port configuration III Configuration procedure 1 Configuring a VLAN Create VLAN 100 SwitchA system view SwitchA vlan 100 Add ports GigabitEthernet1 ...

Page 51: ... Total 1 MAC Group s Port flags D Dynamic port S Static port A Aggregation port C Copy port Subvlan flags R Real VLAN C Copy VLAN Vlan id 100 Total 1 IP Group s Total 1 IP Source s Total 1 MAC Group s Router port s total 2 port GigabitEthernet1 0 1 D 00 01 30 GigabitEthernet1 0 4 S 00 01 30 IP group s the following ip group s match to one mac group IP group address FF1E 1 FF1E 1 Attribute Host Por...

Page 52: ...e IPv6 multicast group policy is not correctly applied z The function of dropping unknown IPv6 multicast data is not enabled so unknown IPv6 multicast data is broadcast z Certain ports have been configured as static member ports of IPv6 multicasts groups and this configuration conflicts with the configured IPv6 multicast group policy III Solution 1 Use the display acl ipv6 command to check the con...

Page 53: ...500 SI Series Ethernet Switches Chapter 2 MLD Snooping Configuration 2 25 whether this configuration conflicts with the configured IPv6 multicast group policy If any conflict exists remove the port as a static member of the IPv6 multicast group ...

Page 54: ...s transmission t VLAN runs Multicast Packets Source HostA Receiver HostC Receiver Receiver HostB VLAN10 VLAN 30 RouterA SwitchA VLAN 30 VLAN10 Receiver Receiver VLAN 20 VLAN 2 VLAN 111 0 Figure 3 1 Before and after multicast VLAN is enabled on the Layer 2 device To solve this problem you can enable the multicast VLAN feature on Switch A namely configure the VLANs to which these hosts belong as sub...

Page 55: ...f the multicast VLAN must not be sub VLANs of another multicast VLAN z The number of sub VLANs of the multicast VLAN must not exceed the system defined limit Currently S5500 SI Series Ethernet Switches only support one multicast VLAN and each one can configure up to 63 sub VLANs Caution After a VLAN is configured into a multicast VLAN Layer 2 multicast must be enabled in the VLAN before the multic...

Page 56: ...osts attached to Switch A need the multicast data II Network diagram HostA HostB HostC RouterA SwitchA GE1 0 1 VLAN1024 GE1 0 2 VLAN11 GE1 0 1 GE1 0 3 VLAN12 GE1 0 4 VLAN13 GE1 VLAN GE VL HostD HostE 0 5 14 1 0 6 AN15 Figure 3 2 Network diagram for multicast VLAN configuration III Configuration procedure 1 Configuring Router A Enable IGMP and PIM DM on GigabitEthernet 1 0 1 RouterA system view Rou...

Page 57: ...ub VLANs SwitchA vlan 1024 SwitchA vlan1024 port GigabitEthernet 1 0 1 SwitchA vlan1024 quit SwitchA multicast vlan 1024 enable SwitchA multicast vlan 1024 subvlan 11 to 15 Enable IGMP Snooping SwitchA igmp snooping SwitchA igmp snooping quit SwitchA vlan 1024 SwitchA vlan1024 igmp snooping enable SwitchA vlan1024 quit 3 Verify the configuration Display information about the multicast VLAN and its...

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