Involved Products and Versions
All versions of modular switches
Networking
In Figure 1-1, ME60-1 and ME60-2 are connected to the Switch through Eth-Trunk3 and Eth-Trunk2 respectively. Multicast subinterfaces of ME60-1 and ME60-2 are Eth-Trunk3.50 and Eth-Trunk2.50 respectively, and PIM is configured on ME60-1 and ME60-2.
Figure 1-1 Networking diagram
Symptom
Both ME60-1 and ME60-2 are DRs, and PIM DR election fails. ME60-1 and ME60-2 forward multicast traffic to the switch separately.
Cause Analysis
Eth-Trunk3 member interface XGE10/0/1 of the Switch has the multicast-suppression packets 0 command configuration. This configuration enables XGE10/0/1 to discard PIM packets.
Procedure
Step 1 Run the display pim interface command on ME60-1 and ME60-2 to view PIM information on interfaces. The command output shows that DR priorities of both ME60-1 and ME60-2 are 1 and their DR addresses are local. This indicates that the Switch does not forward PIM packets normally.
<ME60-1> display pim
interface Eth-Trunk 3.50
VPN-Instance: public net
Interface State NbrCnt HelloInt DR-Pri
DR-Address
Eth-Trunk3.50 up 0
30 1
10.194.163.17 (local)
<ME60-2> display pim
interface Eth-Trunk 2.50
VPN-Instance: public net
Interface State NbrCnt HelloInt DR-Pri
DR-Address
Eth-Trunk2.50 up 1
30 1 10.194.163.18
(local)
Step 2 On the Switch, collect traffic statistics of Eth-Trunk2 and Eth-Trunk3, and then run the display traffic policy statistics interface interface-type interface-number inbound command to view the traffic volume. The command output shows that the Switch receives PIM Hello packet of ME60-2 but does not forward the packet through Eth-Trunk3.
#
acl number 3000
rule 5 permit ip destination 224.0.0.13 0
#
traffic classifier test
if-match acl 3000
#
traffic behavior test
statistic enable
#
traffic policy test
classifier test behavior test
#
interface Eth-Trunk2
traffic-policy test inbound
traffic-policy test outbound
#
interface Eth-Trunk3
traffic-policy test inbound
traffic-policy test outbound
Step 3 Check the configuration of Eth-Trunk3 on the Switch, finding that Eth-Trunk3 member interface XGE10/0/1 has the multicast-suppression packets 0 command configuration. This configuration enables XGE10/0/1 to discard PIM packets. After this command configuration is deleted, this problem is solved.
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