Supermicro L2 User manual

L2 / L3 Switches
IGMP Snooping
Configuration Guide
Revision 1.0

IGMP Snooping Configuration Guide
Supermicro L2/L3 Switches Configuration Guide
2
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Manual Revision 1.0
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Contents
1 IGMP Snooping Configuration Guide .................................................................................................... 4
1.1 IGMP Snooping Basics ................................................................................................................... 4
1.2 IGMP Snooping Support ................................................................................................................ 6
1.3 IGMP Snooping Defaults ............................................................................................................... 6
1.4 Enabling IGMP Snooping ............................................................................................................... 7
1.5 IGMP Version ................................................................................................................................ 8
1.6 Multicast Router Port .................................................................................................................... 9
1.6.1 Router Port Timeout ............................................................................................................. 9
1.6.2 Static Router Port ................................................................................................................ 10
1.7 Leaving Multicast Group ............................................................................................................. 11
1.7.1 Group Query Interval .......................................................................................................... 12
1.7.2 Group Query Retry Count ................................................................................................... 13
1.7.3 Immediate Leave ................................................................................................................. 13
1.8 IGMP Snooping Querier .............................................................................................................. 14
1.9 Report Forward ........................................................................................................................... 16
1.10 Port Timeout (Port Purge Interval) ............................................................................................. 17
1.11 Report Suppression Interval ....................................................................................................... 18
1.12 Proxy Reporting........................................................................................................................... 19
1.13 Send Query when Topology Changes ......................................................................................... 20
1.14 Multicast Forwarding Mode ....................................................................................................... 21
1.15 Disabling IGMP Snooping ............................................................................................................ 22
1.16 IGMP Snooping Configuration Example ...................................................................................... 23

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1IGMP Snooping Configuration Guide
This document describes the IGMP Snooping feature supported in Supermicro Layer 2 / Layer 3 switch
products.
The IGMP Snooping configurations for the below listed Supermicro switch products are covered.
The majority of this document applies to all the above listed Supermicro switch products. In any
particular sub section however, the contents might vary across these switch product models. In those
sections the differences are clearly identified with reference to particular switch product models. If any
particular switch product model is not referenced, the reader can safely assume that the content is
applicable to all the above listed models.
Throughout this document, the common term “switch” refers to any of the above listed
Supermicro switch product models unless a particular switch product model is noted.
1.1 IGMP Snooping Basics
Switches learn the source M C addresses for unicast traffic and forward the unicast traffic only to the
required ports. But for multicast and broadcast traffic, switches forward the traffic to all ports except for
the port that received that traffic. This basic multicast switching function helps all hosts connected to
the switch to receive the multicast traffic.
In practical deployments, all hosts connected to a switch may not run the same multicast applications.
The hosts that do not run multicast applications receive the multicast traffic unnecessarily. Similarly the
Top of Rack Switches
• SSE-G24-TG4
• SSE-G48-TG4
• SSE-X24S
• SSE-X3348S
• SSE-X3348T
Blade Switches
• SBM-GEM-X2C
• SBM-GEM-X2C+
• SBM-GEM-X3S+
• SBM-XEM-X10SM

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multicast traffic is forwarded to other switches unnecessarily when there are no hosts connected to the
other switches expecting the multicast traffic.
Forwarding multicast traffic to unnecessary hosts and switches wastes network bandwidth and
computing resources. In IP TV and other similar multicast intensive deployments, this problem leads to
considerable underutilization of network and compute resources.
Figure IGS-1: Multicast Forwarding without IGMP Snooping
The IGMP snooping function helps the switches to forward IPv4 multicast traffic to only the ports that
require IPv4 multicast traffic. This function saves network bandwidth by preventing the unnecessary
flooding of IPv4 multicast traffic.
switch performs the IGMP snooping function by snooping the Layer 3 IGMP packets and recognizes an
IGMP host’s connected ports by snooping the IGMP join messages sent from hosts. Similarly, a switch
recognizes an IGMP router’s connected ports by snooping the IGMP control messages sent by IGMP
routers. The switch maintains a multicast forwarding table based on the hosts joined and router
connected ports for every multicast group and updates the multicast forwarding table when hosts leave
multicast groups.
switch forwards the multicast traffic based on the information available on the multicast table. It
sends the multicast traffic of any group to only the ports that have hosts joined for that multicast group.
This mechanism prevents the unnecessary flooding of multicast traffic to all the ports.
Switch B
Switch A
Receiver 1 Receiver 2
Multicast
Traffic
Source

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Figure IGS-2: Multicast Forwarding with IGMP Snooping
1.2 IGMP Snooping Support
Supermicro switches support IGMP snooping for all three IGMP versions (1, 2 and 3).
Supermicro switches support forwarding of multicast traffic based on M C and IP addresses.
Supermicro switches support up to 255 multicast groups.
1.3 IGMP Snooping Defaults
Para eter Default Value
IGMP snooping global status
Disabled
IGMP snooping status in VL N
Disabled
Multicast forwarding mode
M C Based
Send query on topology change
Disabled
Proxy report
Enabled
Router port purge interval
125 seconds
Port purge interval
260 seconds
Report forward interval
5 seconds
Group specific query interval
2 seconds
Forwarding reports
To
only
router ports
Group specific query retry count
2
IGMP
version
3
Immediate
leave
(fast leave)
Disabled
Querier
Non
-
querier
Switch B
Switch A
Receiver 1 Receiver 2
Multicast
Traffic
Source

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Query
i
nterval
125 seconds
1.4 Enabling IGMP Snooping
IGMP snooping is disabled by default in Supermicro switches.
IGMP snooping needs to be enabled globally and also needs to be enabled in VL Ns individually.
Follow the steps below to enable IGMP snooping.
Step Co and Description
Step 1
configure ter inal
Enters the configuration mode
.
Step 2
ip ig p snooping
Enables IGMP snooping globally.
Step 3
vlan <
vlan-list
>
Enters the VL N configuration mode.
vlan-list – may be any VL N number or
list of VL N numbers. Multiple VL N
numbers can be provided as comma-
separated values. Consecutive VL N
numbers can be provided as a range,
such as 5-10.
If multiple VL Ns are provided, the next
step will enable IGMP snooping on all
these VL Ns.
Step 4
ip ig p snooping
Enables IGMP snooping
on
VL N.
Step 5
end
Exits the configuration mode.
Step 6
show ip ig p snooping globals
show ip ig p snooping vlan <vlan>
Displays the
IGMP snooping
information.
Step 7
write
startup
-
config
Optional step
–
saves this
IGMP
snooping configuration to be part of
the startup configuration.
The
GMRP feature needs to be in
the
disabled state while enabling IGMP snooping. GMRP is
disabled by default in Supermicro switches.
Use the “set g rp disable” command to disable the GMRP feature if needed.
The example below shows the commands to enable IGMP snooping.
Enable IGMP snooping for VLAN 1, 10 and 20.

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SMIS# configure ter inal
SMIS(config)# ip ig p snooping
SMIS(config)# vlan 1,10,20
SMIS(config-vlan)# ip ig p snooping
SMIS(config-vlan)# end
1. IGMP Version
The IGMP protocol standard has three versions: v1, v2 and v3. Supermicro switches support IGMP
snooping for all three versions. Supermicro IGMP snooping support interoperates with different IGMP
versions as defined in IGMP protocol standard.
The default IGMP snooping version is v3, which works compatible with IGMP versions 1 and 2.
Supermicro switches provide flexibility for user to configure IGMP snooping versions for individual
VL Ns. User can configure different IGMP version on different VL Ns.
Follow the steps below to change IGMP snooping version on any VL N.
Step Co and Description
Step 1
configure ter inal
Enters the configuration mode
.
Step 2
vlan <
vlan-list
>
Enters the VL N configuration mode.
vlan-list – may be any VL N number or
list of VL N numbers. Multiple VL N
numbers can be provided as comma-
separated values. Consecutive VL N
numbers can be provided as a range,
such as 5-10.
If multiple VL Ns are provided, the next
step will be applied on all these VL Ns.
Step 3
ip ig p snooping
version {v1 | v2 | v3}
Configures IGMP snooping version.
Step 5
end
Exits the configuration mode.
Step 6
show ip ig p snooping vlan <
vlan
>
Displays the IGMP
snooping
version
information for the given VL N.
Step 7
write startup
-
config
Optional step
–
saves this IGMP
snooping configuration to be part of
the startup configuration.
The example below shows the commands to configure different versions of IGMP snooping.
Configure IGMP snooping version 3 for VLAN 10 and version 2 for VLAN 20.

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SMIS# configure ter inal
SMIS(config)# vlan 10
SMIS(config-vlan)# ip ig p snooping version v3
SMIS(config-vlan)# exit
SMIS(config)# vlan 20
SMIS(config-vlan)# ip ig p snooping version v2
SMIS(config-vlan)# end
1.6 Multicast Router Ports
Supermicro switches monitor the IGMP control messages sent by IGMP routers and recognize the ports
that receive IGMP router messages as router ports.
switch forwards the IGMP member reports from the host computers to only the router ports. If a
switch does not recognize any router ports, it forwards the host computers’ IGMP reports to all ports
except the one that received the host report’s message.
1.6.1 Router Port Timeouts
fter finding the router ports, switches expect to periodically receive IGMP control messages from
them. If IGMP receives no control messages are for a period of time from any router port, a switch will
stop considering those ports as router ports until IGMP control messages are received again. This period
of time is called the router port timeout value.
By default, Supermicro switches have a router port timeout value of 125 seconds. This value can be
changed by following the steps below.
Step Co and Description
Step 1
configure ter inal
Enters the configuration mode
.
Step 2
ip ig p snooping
router
-
ti e
-
out
<timeout>
Configures the router port
time
out
value in seconds.
timeout – may be any value from 60 to
600 seconds.
The default value is 125 seconds.
Step 3
end
Exits the configuration mode.
Step 4
show ip ig p snooping
globals
Displays the IGMP snooping r
outer port
timeout information.
Step 5
write startup
-
config
Optional step
–
saves this IGMP
snooping configuration to be part of
the startup configuration.
The
“
no ip ig p snooping router
-
ti e
-
out”
command
resets the
router time
out value to
its default value of 125 seconds.

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The example below shows the commands used to configure the router port timeout value.
Configure the router port ti eout value as 90 seconds.
SMIS# configure ter inal
SMIS(config)# ip ig p snooping router-ti e-out 90
SMIS(config)# end
1.6.2 Static Router Ports
Router ports can also be configured statically. Router ports are configured per VL N basis.
Follow the steps below to configure the static router port for any VL N.
Step Co and Description
Step 1
configure ter inal
Enters the configuration mode
.
Step 2
vlan <
vlan-list
>
Enters the VL N configuration mode.
vlan-list – may be any VL N number or
list of VL N numbers. Multiple VL N
numbers can be provided as comma-
separated values. Consecutive VL N
numbers can be provided as a range,
such as 5-10.
If multiple VL Ns are provided, the next
step will configure the router ports for
all these VL Ns.
Step 3
ip ig p snooping
router
<interface-type
>
<interface-id>
Configures
the router port
.
interface-type – may be any of the
following:
gigabit ethernet – gi
extreme ethernet – ex
qx ethernet – qx
port channel – po
interface-id is in slot/port format for all
physical interfaces. It may be the port
channel identifier for port channel
interfaces.
Step 5
end
Exits the configuration mode.
Step 6
show ip ig p snooping
router [
vlan <
vlan
>
]
Displays the IGMP snooping
router port
information. If a VL N identifier is
provided it displays the router port for
the given VL N. If a VL N identifier is
not provided it displays the router ports