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Configuring IGMP and IGMP-Snoop Timers for the EX series Switches

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Article ID: KB15185 KB Last Updated: 04 Mar 2017Version: 2.0
Summary:
Configuring IGMP and IGMP-Snoop Timers and expected behavior.
Symptoms:





 

Solution:
Both igmp timers and igmp-snoop timers values are configurable which results in both settings acting upon the same flow. It is also possible with igmp timers value greater than igmp-snooping timers value that you could get into a scenario where igmp-snoop membership is cleared momentarily. If you need to change the igmp timer values then it is suggest that you set them to a higher value than the current default igmp timer settings. It is important to note that with no igmp-snoop timer configuration, igmp-snoop will inherit the original igmp default timer settings regardless of how you have modified the igmp timer.

NOTE: Unless there are specific application requirements it is recommended that you use the default settings for igmp and igmp-snoop timers.

IGMP-Snoop Timer and IGMP Timer Testing Results and observations

Configured igmp-snoop timers with igmp default timers:

Observed that the interface is removed from the igmp-snooping table when the igmp-snoop timers (set to 50s in this test) have expired, however the igmp group is not removed from the igmp group table until the igmp default timers (default is 260s) value has expired. Note both settings act on the same flow configured for their respective vlans or interfaces

No igmp-snoop timers configured with igmp default timers:

With no igmp-snoop timers parameters configured I observed igmp-snoop membership timers value at 260s. Both the igmp group table and the igmp-snoop tabe were cleared when 260s had experied. Without any igmp-snoop parameter settings igmp inherits the igmp default timers.
No igmp-snoop timers configured with igmp default timers modified:

Observed that without igmp-snoop timers configured igmp-snoop timers inherits igmp default timers value (260s), but does not use the manually configured igmp timersIgmp-snoop timers inherits igmp default timers value (260s) although the igmp defualt timers has been modified

Configured igmp-snoop timers and modified igmp default timers:

Observed with both igmp-snoop timers (set to 60s) and igmp timers (set to 50s) that both tables igmp-snoop and igmp followed their respective timers values configured Although both igmp-snoop timers and igmp timers were manually configured both timers acted upon the same flow

Listed below is a summary of test results which includes observations and command outputs which are useful for troubleshooting IGMP:

1. Configured igmp-snoop timers with igmp default timers

Observed that the interface is removed from the igmp-snooping table when the igmp-snoop timers (set to 50s) has expired, however the igmp group is not removed from the igmp group table until the igmp default timers (default is 260s) value has expired.
{master:0}[edit protocols igmp-snooping]

juniper@L5-23-4200# run show igmp-snooping membership
VLAN: poqr2
225.0.0.8 * 49 secs
Interfaces: ge-1/0/0.0

{master:0}[edit protocols igmp-snooping]

juniper@L5-23-4200# run show igmp group

Interface: vlan.22
Group: 225.0.0.8
Source: 0.0.0.0
Last reported by: 1.1.22.4
Timers: 259 Type: Dynamic
Interface: local
Group: 224.0.0.2
Source: 0.0.0.0
Last reported by: Local
Timers: 0 Type: Dynamic
Group: 224.0.0.22
Source: 0.0.0.0
Last reported by: Local
Timers: 0 Type: Dynamic

{master:0}[edit protocols igmp-snooping]

juniper@L5-23-4200# run show igmp interface
Interface: vlan.22
Querier: 1.1.22.1
State: Up Timers: None Version: 2 Groups: 1
Immediate leave: Off
Promiscuous mode: Off

Configured Parameters:
IGMP Query Interval: 125.0
IGMP Query Response Interval: 10.0
IGMP Last Member Query Interval: 1.0
IGMP Robustness Count: 2

Derived Parameters:
IGMP Membership Timers: 260.0
IGMP Other Querier Present Timers: 255.0

{master:0}[edit protocols igmp-snooping]
Configuration:

{master:0}[edit protocols igmp]
juniper@L5-23-4200# show
interface vlan.22;

{master:0}[edit protocols igmp-snooping]
juniper@L5-23-4200# show
vlan all;
vlan poqr2 {
query-interval 20;
query-last-member-interval 75;
query-response-interval 10;
robust-count 2;
inactive: immediate-leave;
interface vlan.22 {
multicast-router-interface;
}
interface xe-0/1/0.0 {
multicast-router-interface;
}
interface xe-1/1/0.0 {
multicast-router-interface;
}
}


2. No igmp-snoop timers configured with igmp default timers

With no igmp-snoop timers parameters configured I observed igmp-snoop membership timers value at 260s. Both the igmp group table and the igmp-snoop were cleared when 260s had experied.

{master:0}[edit protocols igmp-snooping]

juniper@L5-23-4200# run show igmp-snooping membership

VLAN: poqr2
225.0.0.8 * 257 secs
Interfaces: ge-1/0/0.0

{master:0}[edit protocols igmp-snooping]

juniper@L5-23-4200# run show igmp group
Interface: vlan.22
Group: 225.0.0.8
Source: 0.0.0.0
Last reported by: 1.1.22.4
Timers: 238 Type: Dynamic
Interface: local
Group: 224.0.0.2
Source: 0.0.0.0
Last reported by: Local
Timers: 0 Type: Dynamic
Group: 224.0.0.22
Source: 0.0.0.0
Last reported by: Local
Timers: 0 Type: Dynamic

{master:0}[edit protocols igmp-snooping]

juniper@L5-23-4200# run show igmp interface
Interface: vlan.22
Querier: 1.1.22.1
State: Up Timers: None Version: 2 Groups: 0
Immediate leave: Off
Promiscuous mode: Off

Configured Parameters:

IGMP Query Interval: 125.0
IGMP Query Response Interval: 10.0
IGMP Last Member Query Interval: 1.0
IGMP Robustness Count: 2

Derived Parameters:

IGMP Membership Timers: 260.0
IGMP Other Querier Present Timers: 255.0

Configuration:


{master:0}[edit protocols igmp]

juniper@L5-23-4200# show

interface vlan.22;

{master:0}[edit protocols igmp-snooping]

juniper@L5-23-4200# show

vlan all;
vlan poqr2 {
inactive: query-interval 20;
inactive: query-last-member-interval 75;
inactive: query-response-interval 10;
inactive: robust-count 2;
inactive: immediate-leave;

3. No igmp-snoop timers configured with igmp default timers modified

Observed that without igmp-snoop timers configured igmp-snooping timers inherits igmp default timers values, but does not use the manually configured igmp timers.


{master:0}[edit protocols igmp]

juniper@L5-23-4200# run show igmp-snooping membership

VLAN: poqr2
225.0.0.8 * 259 secs
Interfaces: ge-1/0/0.0

{master:0}[edit protocols igmp]
juniper@L5-23-4200# run show igmp group
Interface: vlan.22
Group: 225.0.0.8
Source: 0.0.0.0
Last reported by: 1.1.22.4
Timers: 49 Type: Dynamic

master:0}[edit protocols igmp]
juniper@L5-23-4200# run show igmp interface
Interface: vlan.22
Querier: 1.1.22.1
State: Up Timers: None Version: 2 Groups: 0
Immediate leave: Off
Promiscuous mode: Off

Configured Parameters:
IGMP Query Interval: 20.0
IGMP Query Response Interval: 10.0
IGMP Last Member Query Interval: 1.0
IGMP Robustness Count: 2

Derived Parameters:
IGMP Membership Timers: 50.0
IGMP Other Querier Present Timers: 45.0

Configuration:

juniper@L5-23-4200# show
vlan all;
vlan poqr2 {
inactive: query-interval 20;
inactive: query-last-member-interval 75;
inactive: query-response-interval 10;
inactive: robust-count 2;
inactive: immediate-leave;
interface vlan.22 {
multicast-router-interface;
}
interface xe-0/1/0.0 {
multicast-router-interface;
}
interface xe-1/1/0.0 {
multicast-router-interface;
}
}

{master:0}[edit protocols igmp]
juniper@L5-23-4200# show
query-interval 20;
query-response-interval 10;
robust-count 2;
interface vlan.22;


4. Configured igmp-snoop timers and modified igmp default timers

Observed with both igmp-snoop timers (set to 60s) and igmp timers (set to 50s) that both tables igmp-snoop and igmp followed the respective timers values configured.

{master:0}[edit protocols igmp-snooping]
juniper@L5-23-4200# run show igmp-snooping membership
VLAN: poqr2
225.0.0.8 * 59 secs
Interfaces: ge-1/0/0.0

{master:0}[edit protocols igmp-snooping]
juniper@L5-23-4200# run show igmp group
Interface: vlan.22
Group: 225.0.0.8
Source: 0.0.0.0
Last reported by: 1.1.22.4
Timers: 49 Type: Dynamic
Interface: local
Group: 224.0.0.2
Source: 0.0.0.0
Last reported by: Local
Timers: 0 Type: Dynamic
Group: 224.0.0.22
Source: 0.0.0.0
Last reported by: Local
Timers: 0 Type: Dynamic

{master:0}[edit protocols igmp-snooping]
juniper@L5-23-4200# run show igmp interface
Interface: vlan.22
Querier: 1.1.22.1
State: Up Timers: None Version: 2 Groups: 1
Immediate leave: Off
Promiscuous mode: Off

Configured Parameters:
IGMP Query Interval: 20.0
IGMP Query Response Interval: 10.0
IGMP Last Member Query Interval: 1.0
IGMP Robustness Count: 2

Derived Parameters:
IGMP Membership Timers: 50.0
IGMP Other Querier Present Timers: 45.0

Configuration:

{master:0}[edit protocols igmp-snooping]
juniper@L5-23-4200# show
vlan all;
vlan poqr2 {
query-interval 25;
query-last-member-interval 75;
query-response-interval 10;
robust-count 2;
inactive: immediate-leave;
interface vlan.22 {
multicast-router-interface;
}
interface xe-0/1/0.0 {
multicast-router-interface;
}
interface xe-1/1/0.0 {
multicast-router-interface;
}
}

{master:0}[edit protocols igmp]

juniper@L5-23-4200# show
query-interval 20;
query-response-interval 10;
robust-count 2;
interface vlan.22;

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