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The Graveyard - Products No Longer Supported => Hubs and Switches => DGS-1224T => Topic started by: svenstorp on November 16, 2009, 10:52:54 AM

Title: Multicast is by default broadcasted even with IGMP snooping turned on
Post by: svenstorp on November 16, 2009, 10:52:54 AM

Hi

We have a multicast source connected to a DGS-1224T with IGMP snooping enabled. However the multicast traffic is broadcasted throughout the VLAN until a host sends an IGMP join message. When first IGMP message arrives, the traffic is correctly sent only on the port where the IGMP message were received. The host can later send a IGMP leave message, and the multicast traffic will stop flowing through the switch.

So to sum the behaviour of the switch:
1. Switch boots up
2. Multicast traffic is broadcasted on all ports
3. Client sends IGMP join message
4. Multicast traffic is forwarded to port(s) where join message were received
5. Client sends IGMP leave message
6. No multicast traffic is forwarded.

In my opinion, number 2 should be equal to number 6? Am I missing something? A setting?

Any thoughts?

Device type: DGS-1224T
Firmware: 4.21.01
HW rev: D2