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reedstlouis
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IGMP snooping multicast issue DELL 4032f MLAG connection to Cisco switch

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We have been moving to the DELL 4032f  MLAG connected switch as the core of a CCTV network with a Cisco 4510 as a LAG connection to the older network.  We can not seem to get MULTICASTING traffic to pass over the DELL to CISCO LAG link.  Multicast groups show up on DELL side of port channel but not the Cisco Side so CISCO side of network never seems to see the multicast traffic

CISCO MULTICAST GROUPS

4510#sh ip ig snooping groups vlan 27
Vlan Group Version Port List
---------------------------------------------------------
27 239.1.1.1 v2 Te2/3, Po2
27 239.1.1.2 v2 Te2/3, Po2
27 239.1.1.3 v2 Te2/3, Po2
27 239.1.1.4 v2 Te2/3, Po2

TE2/3 edge cisco switch old CCTV core

Po2 port channel to another Cisco switch with subscriber to stream

ip querier configured on DELL n2024 edge switch connected to the MLAG

4510#sh ip ig snooping querier vlan 27
IP address : 172.28.232.2
IGMP version : v2
Port : Po1
Max response time : 10s

Po1 port channel to the DELL 4032f MLAG switch no groups 

DELL primary vpc switch

2-4032f#show ip igmp snooping groups vlan 27

Vlan Group Type OIFs
---- ----------------------- ------- ----------------------------------------
27 224-239.129|1.1.1 Dynamic Po1,Po7
27 224-239.129|1.1.2 Dynamic Po1,Po7
27 224-239.129|1.1.3 Dynamic Po1,Po7
27 224-239.129|1.1.4 Dynamic Po1,Po7
27 224-239.168|40.168.168 Dynamic Po1,Po7

Po1 port channel interlink port channel of MLAG

Po7 port channel port channel to CISCO 4510 switch

2-4032f#show ip igmp snooping querier vlan 27

Vlan 27 : IGMP Snooping querier status
----------------------------------------------
IGMP Snooping Querier Vlan Mode................ Disable
Querier Election Participate Mode.............. Disable
Querier Vlan Address........................... 0.0.0.0
Operational State.............................. Disabled
Last Querier Address........................... 172.28.232.2
Operational version............................ 2
Operational Max Resp Time...................... 11

DELL vpc secondary switch

4-4032f#show ip igmp snooping groups vlan 27

Vlan Group Type OIFs
---- ----------------------- ------- ----------------------------------------
27 224-239.129|1.1.1 Dynamic Po1,Po23
27 224-239.129|1.1.2 Dynamic Po1,Po23
27 224-239.129|1.1.3 Dynamic Po1,Po23
27 224-239.129|1.1.4 Dynamic Po1,Po23
27 224-239.168|40.168.168 Dynamic Po1,Po23

Po1 port channel interlink port channel of MLAG

Po23 port channel port channel to DELL switch with subscriber to stream

4-4032f#show ip igmp snooping querier vlan 27

Vlan 27 : IGMP Snooping querier status
----------------------------------------------
IGMP Snooping Querier Vlan Mode................ Disable
Querier Election Participate Mode.............. Disable
Querier Vlan Address........................... 0.0.0.0
Operational State.............................. Disabled
Last Querier Address........................... 172.28.232.2
Operational version............................ 2
Operational Max Resp Time...................... 11

DELL edge switch on connect to MLAG switch on port channel 1 with querier address

4-2024#show ip igmp snooping querier vlan 27

Vlan 27 : IGMP Snooping querier status
----------------------------------------------
IGMP Snooping Querier Vlan Mode................ Enable
Querier Election Participate Mode.............. Disable
Querier Vlan Address........................... 172.28.232.2
Operational State.............................. Querier
Operational version............................ 2
Operational Max Resp Time...................... 10

4-2024#show ip igmp snooping groups vlan 27

Vlan Group Type OIFs
---- ----------------------- ------- ----------------------------------------
27 224-239.129|1.1.1 Dynamic Po1,Gi1/0/15-18
27 224-239.129|1.1.2 Dynamic Po1,Gi1/0/15-18
27 224-239.129|1.1.3 Dynamic Po1,Gi1/0/15-18
27 224-239.129|1.1.4 Dynamic Po1,Gi1/0/15-18
27 224-239.168|40.168.168 Dynamic Po1
27 224-239.255|127.255.250 Dynamic Gi1/0/11

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RE: IGMP snooping multicast issue DELL 4032f MLAG connection to Cisco switch

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Unfortunately, you probably wont be able to get multicast to work with this MLAG setup. If we look at the features synchronized between MLAG peers, IGMP snooping is not one of them.

Page 1023: http://dell.to/1WFiTWT

the following white paper indicates that MLAG does not meet the criteria for passing multicast traffic, and suggests to instead use a stack setup.

Page 14: http://dell.to/1FwsBOG

Daniel Covey
Dell EMC| Enterprise Support Services
Get support on Twitter:@DellCaresPRO
Download our QRL app:iOS, Android, Windows
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reedstlouis
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RE: IGMP snooping multicast issue DELL 4032f MLAG connection to Cisco switch

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Thanks for your answer, that is extremely disappointing. 

I do have another question about the stack solution. We had the MLAG switches separated about a mile one in each data center,  If we switch the MLAG core to a stack using the existing fiber connections is there any distance limitations between them?

Also we had a two trier MLAG configuration with two of the switches in one datacenter and their partner switch in one of two other data centers.  So if distance is not an issue I am assuming that I could merge all four switches into one big stack?

Thanks again for your reply.

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RE: IGMP snooping multicast issue DELL 4032f MLAG connection to Cisco switch

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I did not see anything in the guides that indicated a distance limitation. However I would not recommend stacking switches from different buildings together. the long distance may possibly cause unforeseen issues. firmware updates would be a huge pain, as the entire stack needs to reboot at the same time, causing all 4 sites to be down at the same time. There can also be some packet loss if the master switch goes down, which would cause all 4 locations to see this packet loss.

With 2 switches in the same building, stacking those would be feasible. But then the switches a mile apart from one another, I would leave those as independent switches.

Daniel Covey
Dell EMC| Enterprise Support Services
Get support on Twitter:@DellCaresPRO
Download our QRL app:iOS, Android, Windows
Dell Networking Resources

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