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Page 104 | AlliedWare™ OS How To Note: IGMP
IGMP debugging > Example
Client 2 sends a Leave message for group 224.
1
2.
1
3.
1
4. Switch
1
sees the Leave message on
vlan
1
00 (port 49). The port is in a state of “deferred deletion” because of the Last Member
Query process (see "Last Member Query Count and Last Member Query Interval" on
page 72).
Switch
1
is an IGMP Querier, so it sends out two Membership Queries and waits 2 seconds
for a response. None arrives, so switch
1
deletes the entry.
Several minutes later the group entry times out.
Meanwhile, switch 3, which has the client attached to it, sees the same sequence but debugs
it differently. Like switch
1
, switch 3 logs the Leave message, but its output also includes the
port on which it received the Leave message. This enables you to identify the client. Switch 3
also logs the two Specific Queries and notes the 2 second timeout. After 2 seconds it also
deletes the entry from its IGMP snooping table.
X A client leaves a group
Manager Switch 1> IGMP Snoop(48) on vlan100: Leave -> IGMP Snoop(48): Leave g.
group 224.12.13.14 - Port 49 in deferred deletion.
IGMP Rx(48) on vlan100: Leave -> IGMP Rx(48): Leave group=224.12.13.14 -> group .
Manager Switch 1> IGMP Snoop Timeout: group=224.12.13.14 (0) is deleted
Deleting all ports for group 224.12.13.14 on vlan100
IGMP Timeout: group=224.12.13.14 (0) is deleted
Manager Switch 3> IGMP Snoop: resending pkt to vlan
utPorts: 1-4,6-26 fwdPorts: 26
IGMP Snoop(2) on vlan100: Leave -> IGMP Snoop(2): Leave group=224.12.13.14-> gr.
group 224.12.13.14 - Port 3 in deferred deletion.
IGMP MVR Snoop: discard - no MVR snooper for code 23
IGMP Snoop: resending pkt to vlan
utPorts: 1-4,6-26 fwdPorts: 3,26
IGMP Snoop(25) on vlan100: Query -> code 10
igmpSnoopMembershipQuery >> setting timer at 2 secs for group 224.12.13.14
snooped group 224.0.0.2 added
Adding port 26 for group 224.0.0.2 on vlan100
IGMP MVR Snoop: discard - no MVR snooper for code 17
Manager Switch 3> IGMP Snoop: resending pkt to vlan
utPorts: 1-4,6-26 fwdPorts: 3,26
IGMP Snoop(25) on vlan100: Query -> code 10
igmpSnoopMembershipQuery >> setting timer at 2 secs for group 224.12.13.14
snooped group 224.0.0.2 added
Adding port 26 for group 224.0.0.2 on vlan100
IGMP MVR Snoop: discard - no MVR snooper for code 17
Manager Switch 3> IGMP Snoop Timeout: group=224.12.13.14 (0) is deleted
Deleting all ports for group 224.12.13.14 on vlan100