Dell EMC SmartFabric OS10 User Guide Release 10.5.1

IGMP snooping

IGMP snooping uses the information in IGMP packets to generate a forwarding table that associates ports with multicast groups. When switches receive multicast frames, they forward them to their intended receivers. OS10 supports IGMP snooping on virtual local area network (VLAN) interfaces.

Effective with OS10 release 10.4.3.0, IGMP snooping is enabled by default.

Configuration notes

All Dell EMC PowerSwitches except MX-Series, S4200-Series, S5200 Series, and Z9332F-ON:

If you configure and unconfigure a static connection to a multicast router on an interface using the ip igmp snooping mrouter interface command in VLAN mode, the router port still appears in the show ip igmp snooping mrouter vlan output. To remove the VLAN port from the show output, configure the VLAN port again using the ip igmp snooping mrouter interface command, and then unconfigure it using the no version of the command.

Configure IGMP snooping

• Enable IGMP snooping globally using the ip igmp snooping enable command in CONFIGURATION mode. This command enables IGMP snooping on all VLAN interfaces.
  NOTE: You cannot enable IGMP or MLD snooping when configuring VLAN scale profile. If you enable VLAN scale profile, OS10 disables IGMP and MLD snooping globally. When you disable VLAN scale profile configuration, you must explicitly enable IGMP and MLD snooping globally.
• (Optional) Disable IGMP snooping on specific VLAN interfaces using the no ip igmp snooping command in VLAN INTERFACE mode.
• (Optional) Multicast flood control is enabled by default. To disable the multicast flood restrict feature, use the no multicast snooping flood-restrict command in CONFIGURATION mode. To reenable the feature globally, use the multicast snooping flood-restrict command in CONFIGURATION mode.
• In a network, the snooping switch is connected to a multicast Router that sends IGMP queries. On a Layer 2 network that does not have a multicast router, you can configure the snooping switch to act as querier. Use the ip igmp snooping querier command in VLAN INTERFACE mode to send the queries.
• OS10 learns the multicast router interface dynamically based on the interface on which IGMP membership query is received. To assign a multicast router interface statically, use the ip igmp snooping mrouter interface interface—type command in VLAN INTERFACE mode.
  NOTE:

  IGMP snooping dynamically detects the mrouter interface based on IGMP queries that it receives. If there are more than one multicast routers connected to the snooping switch, one of them will send IGMP queries and the interface connected to that router is dynamically learnt as an mrouter port. You must configure the interfaces connected to other multicast routers as static mrouter port.

• (Optional) Configure the IGMP version using the ip igmp version version-number command in VLAN INTERFACE mode.
• (Optional) The fast leave option allows the IGMP snooping switch to remove an interface from the multicast group immediately on receiving the leave message. Enable fast leave with the ip igmp snooping fast-leave command in VLAN INTERFACE mode.
• (Optional) Configure the time interval for sending IGMP general queries with the ip igmp snooping query-interval query-interval-time command in VLAN INTERFACE mode.
• (Optional) Configure the maximum time for responding to a query advertised in IGMP queries using the ip igmp snooping query-max-resp-time query-response-time command in VLAN INTERFACE mode.
• (Optional) Configures the time interval between group-specific IGMP query messages with the ip igmp snooping last-member-query-interval query-interval-time command in VLAN INTERFACE mode.

OS10(config)# ip igmp snooping enable
OS10(config)# interface vlan 100
OS10(conf-if-vl-100)# ip igmp snooping mrouter interface ethernet 1/1/32
OS10(conf-if-vl-100)# ip igmp snooping querier
OS10(conf-if-vl-100)# ip igmp version 3
OS10(conf-if-vl-100)# ip igmp snooping fast-leave
OS10(conf-if-vl-100)# ip igmp snooping query-interval 60
OS10(conf-if-vl-100)# ip igmp snooping query-max-resp-time 10
OS10(conf-if-vl-100)# ip igmp snooping last-member-query-interval 1000

OS10# show ip igmp snooping groups
Total Number of Groups: 480
IGMP Connected Group Membership
Group Address                 Interface           Mode           Expires
225.1.0.0                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.1                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.2                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.3                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.4                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.5                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.6                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.7                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.8                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
225.1.0.9                     vlan3531            IGMPv2-Compat  00:01:35
  Member-ports :port-channel41,ethernet1/1/51,ethernet1/1/52
--more--  

<<Output Truncated>>

OS10# show ip igmp snooping interface vlan 2
Vlan2 is up, line protocol is up
IGMP version is 3
IGMP snooping is enabled on interface
IGMP snooping query interval is 60 seconds
IGMP snooping querier timeout is 130 seconds
IGMP snooping last member query response interval is 1000 ms
IGMP Snooping max response time is 10 seconds
IGMP snooping fast-leave is disabled on this interface
IGMP snooping querier is disabled on this interface
Multicast flood-restrict is enabled on this interface

show ip igmp snooping mrouter
Interface    Router Ports
Vlan 100      ethernet 1/1/32