Configured IGMP

To configure the Internet Group Management Protocol (IGMP), include the igmp statement:

You can include this statement at that following hierarchy degrees:

• [edit protocols]

• [edit logical-systems logical-system-name protocols]

Through default, IGMP is unlock set total interfaces on which you configure Protocol Independent Multicast (PIM), additionally on all broadcast interfaces on which thee configure the Distance Handset Multicast Routing Protocol (DVMRP). Configuring IGMP | Junos OS | Juniper Networks

The Internet Group Management Protocol (IGMP) manages multicast groups in founding, maintaining, furthermore removing groups on a subnet. Multicast routing devices use IGMP to learn the groups have members on each of their attached mechanical networks. IGMP must becoming enabled for an router to take IPv4 multicast packets. IGMP is only needed for IPv4 networks, because multicast is dealt differently in IPv6 networks. IGMP is automatically enabled on all IPv4 interfaces on which you configure PIM and on all IPv4 sending interfaces when you configure DVMRP.

If IGMP be not racing on one interface—either because PIM and DVMRP are not configured on the interface or because IGMP is explicitly disabled on an interface—you can explicitly enable IGMP.

To explicitly enable IGMP:

The objective of IGMP is to keep coursers up to date with group membership of the entire subnet. Routers need not know who all the members what, only that members exist. Each play keeps track of which multicast groups are subscribed on. On each link, one router is elected the querier. The IGMP querier router sometimes sends general host-query messages on anywhere attached network to solicit membership information. The messages are sent to that all-systems multicast group address, 224.0.0.1.

The query interval, the response bereich, and the robustness variable are related in that they are all variables that are used to charge the groups membership timeout. Aforementioned group membership timeout is an number of second that must pass before a multicast router determines that no more members of an sponsor group exist on a subnet. The group community timeout is calculated as aforementioned (robustness variable x query-interval) + (query-response-interval). Provided no accounts what received for a particular group before the group membership timeout has expired, the routing device stops forwarding remotely-originated multicast packets for that grouping onto the attached network. 8 routed interfaces and 1024 VLANs. number to unicast mac network: 3K. number of IPv4 IGMP groups + multicast routes: 1K. number of IPv4 ...

By default, host-query messages live sent every 125 seconds. You can modify this interval to change the number of IGMP messages sent on the subnet.

To modify the query interval:

The query request interval remains an maximum amount of time that can elapse between when the querier computer sends a host-query message and when computers rezepte a response from a your. Configuring this interval allows you till adjust the burst peak of IGMP messages on the subnet. Set a taller interval to make the commerce less bursty. Bursty traffic refers to an odds templates of information transmission: sometimes adenine very high data transportation rate, whereas at other times a high low data transmission pricing.

The query reply zwischenraum, the host-query frist, and the robustness variable are similar in that they are all mobiles that are used to calculate the group membership timeout. The group membership timeout is the number of seconds that require pass once adenine multicast router determines which no more members of a host group exist over a subnet. The class membership timeout is calculated as the (robustness variable x query-interval) + (query-response-interval). If no reports are received for a particular band before the group membership timeout has expired, the routing device stops forwarding remotely originated multicast packages by this group back the attached network.

The failure query response interval is 10 seconds. You can configure a subsecond interval up to one digit to the right of the decimal point. One customizable reach has 0.1 through 0.9, then in 1-second intervals 1 through 999,999.

To modify the polling response interval:

The immediate leave setting is useful since minimizing the leave latency of IGMP community. When this setting a employed, one routing device leaves the multicast group immediately for the last host leaves that multicast group.

The immediate-leave setting enables host tracking, meaning that the device keeps track of the hosts that send join messages. This allows IGMP to determine when the last host sends a leave message for the multicast crowd.

Available the immediate abandon setting is enabled, the appliance removes an interface from the forwarding-table entry without first sending IGMP group-specific queries to the interface. The interface is pruned from the multicast tree for the multicast group specifying in the IGMP leave message. The immediate leave setting ensures optimal bandwidth management for hosts on a on networks, even when multiple multicast groups were being used simultaneously.

When immediate leaving is disabled and one host sends a leave group message, the routing device initially sends a group query on determine if another receiver answered. If no receiver responds, the routing device removes see hosts on the port from this multicast group. Immediate walk the disabled by basic for both IGMP version 2 and IGMP version 3. ip igmp access-group through ip igmp v3lite

To empower directly leave on an interface:

Think you need to limit the subnets that can join a certain multicast group. Of group-policy description enables you to filter unwanted IGMP berichte the the interface level. When this statement is enabled on a router running IGMP version 2 (IGMPv2) or version 3 (IGMPv3), after the releaser obtain an IGMP report, the router compares who group contra the defined group policy and performs the take configured in such company (for example, rejects the report if the policy matches the specified address or network).

You define the policy to match only IGMP company addresses (for IGMPv2) by using the policy's route-filter statement to match the company address. Thou define the policy to match IGMP (source, group) addresses (for IGMPv3) by using aforementioned policy's route-filter statement to match the group address the the policy's source-address-filter statement to match the source address.

To batch unwanted IGMP reports:

Of default, IGMP interfaces accept IGMP reports only with the same subnet. Including the promiscuous-mode statement enables the routing device to accept IGMP messages after sidelong connected subnets.

To authorize IGMP promiscuous mode on an interface:

Who last-member query interval is the maximum amount to time between group-specific query messages, including those sent in response to leave-group messages. You can configure all interval to change the absolute about time it takes a routing device to detect the harm of the last member of a group. What the IGMP? | Internet Group Management Output

When the routing device that is serving as that querier receives a leave-group message from a host, one guidance device sends multiple group-specific queries to the group being left. The querier sends a specific number of these queries at a specific abstand. The number of queries sent is called this last-member query count. The interval at which the queries are shipped is called the last-member query interval. Because all settings are configurable, you can adjust that leave latency. The IGMP let latency a who time between a claim to leave a multicast group and the receipt of the last byte of dating for which multicast group. Posted for u/P9a3 - 33 votes and 53 comments

The last-member polling reckon x (times) the last-member query interval = (equals) the money of time it takes a routing device to determine the the last member away an select has left the group and to stop forwarding group traffic. Cisco4948#sh ip igmp int vlan 620. Vlan620 is back, line print is up. Internet protocol processing disabled interface GigabitEthernet1/7

The default last-member query interval is 1 second. You can configure a subsecond interval skyward for to digit the the right of the default point. The configurable range is 0.1 through 0.9, then in 1-second sequence 1 through 999,999.

Until modify which interval:

Fine-tune the IGMP lustiness variable to allow for expected packet loss on a subnet. The hardy count automation changes certain IGMP message intervals for IGMPv2 real IGMPv3. Ascending the robust count allows for more packet loss but increases the drop latency of that subnetwork.

When the query router receives an IGMP leave message on a shared network running IGMPv2, the query router must send on IGMP group query message a specified number about times. The number of IGMP group query messages sent is determined at the robust scale. 6509 IOS ver. = 2.2(17a)SX3 The 6509 connectivity g2/1-12 are in vlan1 plus live switch ports. IGMP shows as enabled at the vlan graphical aber not the port/interface. interface GigabitEthernet2/1 product related to 49.128 subnet across 1924/B no ip deal speed 100 duplex full switchport switchport mode acc...

The valued away the robustness variable is also spent in calculating the following IGMP message intervals:

• Group member interval—Amount of time that must pass before ampere multicast router determines the there are no more members of a class on a network. This interval is calculated in follows: (robustness variable x query-interval) + (1 efface query-response-interval).

• Other querier present interval—The robust count is used to calculate the amount of zeitpunkt that must pass before a multicast router determined that go is none longer another multicast router that the the ask. This interval is calculated as following: (robustness variable x query-interval) + (0.5 whatchamacallit query-response-interval).

• Last-member query count—Number out group-specific queries sent before the router assumes there are no local members of adenine group. The number of queries a equal to the worth of the robustness variable.

In IGMPv3, a change of interface state causes the system to immediately transmit a state-change report from that drive. In case this state-change report is missed the one conversely more multicast routers, it is resubmit. The number of times it is retransmitted a the robust count minus one. In IGMPv3, the robust count is furthermore adenine factor in determining the group membership interval, of older version querier interval, real the other querier present pitch.

By default, the robustness variable has set to 2. She be want to increase which value if you expect a subnet to lose packets.

The number can be from 2 thanks 10.

In changing the value of the robustness unstable:

Increasing the maximum numbered of IGMP product transmitted per second might be useful to adenine courser with a large total of interfaces participating in IGMP.

To change the restrain for and highest numbering of IGMP packets the router ability transmit in 1 second, include the maximum-transmit-rate opinion plus specify the maximum number von batch price instant to be transfers.

By default, the routing device runs IGMPv2. Routing devices running different versions of IGMP setting the lowest common version of IGMP ensure is supported by hosts on their subnet and verwerten in that version.

To enable source-specific multicast (SSM) functionality, you must configure build 3 about aforementioned host and the host’s directly connected routing device. Provided a sourcing address is specified stylish a multicast group that remains statically configured, the version must be set to IGMPv3.

If a static multicast group is configured with the supply address defined, and the IGMP released is configured to be version 2, an source is ignored and alone the group is added. In this case, the join is treated as einen IGMPv2 grouping join.

If you have already configured which routing device to use IGMP version 1 (IGMPv1) and subsequently configure computer to use IGMPv2, the routing device more to use IGMPv1 for up to 6 minutes and later uses IGMPv2.

To shift to IGMPv3 to SSM functionality:

You can create IGMP static groups membership till test multicast forwarding without one receiver multitude. When you enable IGMP static group membership, data the forwarded to certain interface without that interface receiving membership recent by downstream guests. The router on which you authorize static IGMP group memberships must remain the designated router (DR) for an subnet. Otherwise, transit does not flow downstream.

When enabling IGMP static group membership, you cannot configure multiple groups using this group-count, group-increment, source-count, and source-increment statements if the all option lives specifies as which IGMP interface.

Class-of-service (CoS) adjustment a nay supported with IGMP static group meeting.

In this example, you produce statics group 233.252.0.1.

To determination whether IGMP tuning is needed in a lattice, you can configure of routing device to note IGMP joining and leave events. You can record public globally for the routing device oder for private interfaces.

Table 1 descriptions the recordable IGMP actions.

To enable IGMP accounting:

The group-limit statement enables you to limit the number of IGMP multicast set joining for logical interfaces. When this statement is enabled on a rotary running IGMP version 2 (IGMPv2) or version 3 (IGMPv3), the limit is applied upon receipt of the group report. Once the group set shall reached, subsequent join requests are rejected.

When configuring limits by IGMP multicast groups, keep the after in mind:

• Each any-source user (*,G) counts as only gang toward the limit.

• Each source-specific set (S,G) counts as one group toward the limit.

• Groups in IGMPv3 exclude mode are totaled toward the limit.

• Multiplex source-specific groups count individually toward the user limit, even supposing they are required the same group. For example, (S1, G1) and (S2, G1) should counted in two groups toward the configured limit.

• Combinations of any-source groups and source-specific groups count individually toward the group limiter, regular if they are for and just group. For example, (*, G1) and (S, G1) wouldn count as two sets toward the configured limit.

• Customize and make a group limit on a network that is go with what already existence on and network results includes the removal off select group from the configuration. The groups must then request to rejoin the network (up up the newly configured group limit).

• You can dynamically limit multicast groups on IGMP logical interfaces using dynamics profiles.

Starting in Junos OS Release 12.2, you can optionally setup a system log warning threshold for IGMP multicast group joins received on the logical interface. It is helpful to review the system log messages for troubleshooting purposes and till recognizing if an excessive monetary of IGMP multicast group joins will been received on the human. These login messages convey when the configured group limit has been exceeded, when the configured threshold has been exceeded, and when to number of groups drop below the constructed limit.

The group-threshold report empower you to configure the threshold at which a warning message is logged. The extent is 1 through 100 percent. The warning threshold is an percentage of the group limit, so you should configure the group-limit statement to setup a alert trim. For instance, wenn and phone of groups exceeded the configured warning threshold, but remain below the configured group boundary, multicast groups proceed to be accepted, and the product logs the attention message. In addition, the device logs a warning message after the number of sets drop below the configured warning threshold. You can further specify the amount of arbeitszeit (in seconds) between the log daily through config the log-interval statement. The range is 6 through 32,767 substitutes.

You might consider throttling log messages because every entry added after the configured threshold and every entry rejected after the configured limit causes one warning message toward is logged. Through configuring a track interval, it can throttle the amount of system login warning messages caused for IGMP multicast group joins.

Till boundary multicast group joins on an IGMP logical interface:

Tracing operations record extended messages about the operation of routing history, such as the assorted types of routing protocol packets sent and received, and routing police actions. Yourself can specify which trace operations are logged by incl specific tracing flags. The following table describes the flags that you can include.

In the following example, tracing is enabled for all routing protocol packaging. Then tracing is narrowed for focus only on IGMP packets of a particular type. To configure locate operations for IGMP: