02-18-2014 05:56 AM - edited 03-07-2019 06:16 PM
Hi,
We've got two 4500-X as VSS configured and 3750-X as Access Switches. We want to use IPTV Multicast in this Network. The Core is configured as PIM Multicast Router in Sparse-Dense Mode and the Access Switches are snooping for IGMP Pakets. After connecting a Client asking for Multicast Stream (239.15.14.16) the Mac Address Table on the Access Switch is empty:
#show mac address-table multicast
Vlan Mac Address Type Ports
---- ----------- ---- -----
But it recognizes the Group the Client is asking for:
#show ip igmp snooping group
Vlan Group Type Version Port List
-----------------------------------------------------------------------
150 239.15.14.16 igmp v2 Gi1/0/3, Po2
The IGMP Snooping Settings on the Access Switch looks like this:
Global IGMP Snooping configuration:
-------------------------------------------
IGMP snooping : Enabled
IGMPv3 snooping (minimal) : Enabled
Report suppression : Enabled
TCN solicit query : Disabled
TCN flood query count : 2
Robustness variable : 2
Last member query count : 2
Last member query interval : 1000
Vlan 150:
--------
IGMP snooping : Enabled
CAPWAP enabled : Disabled
IGMPv2 immediate leave : Enabled
Multicast router learning mode : pim-dvmrp
CGMP interoperability mode : IGMP_ONLY
Robustness variable : 2
Last member query count : 2
Last member query interval : 1000
Why is the Multicast Mac-Address table empty? Any Ideas?
Thanks,
Marc
11-01-2016 11:02 AM
I have this same problem. Did you ever figure it out?
11-02-2016 10:04 AM
Hi Ralphy006
Only the IGMP Querier / PIM Router is showing entries in the "show mac address-table multicast" table. The access switches only care about IGMP snooping groups which can be seen with "show ip igmp snooping groups".
regards,
Marc
11-03-2016 06:37 AM
Thanks Marc. That's interesting.
On a somewhat related note.... do you know if the end-device automatically populates the destination mac-address for a multicast frame? I am aware there is always a correlating mac-address for every IP multicast address. But wasn't sure if there was still something similar to "ARP". Or if the end-device talking multicast just auto populates the destination mac.
Thanks in advance!
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