Defining Multicast Properties
The Properties page enables you to configure the Bridge Multicast filtering status.
By default, all Multicast frames are flooded to all ports of the VLAN. To selectively forward only to relevant ports and filter (drop) the Multicast on the rest of the ports, enable Bridge Multicast filtering status in the Properties page.
If filtering is enabled, Multicast frames are forwarded to a subset of the ports in the relevant VLAN as defined in the Multicast Forwarding Data Base. Multicast filtering is enforced on all traffic. By default, such traffic is flooded to all relevant ports, but you can limit forwarding to a smaller subset.
A common way of representing Multicast membership is the (S,G) notation where āSā is the (single) source sending a Multicast stream of data, and āGā is the IPv4 or IPv6 group address. If a Multicast client can receive Multicast traffic from any source of a specific Multicast group, this is written as (*,G).
The following are ways of forwarding Multicast frames:
- MAC Group Address--Based on the destination MAC address in the Ethernet frame.
NOTE As mentioned before, one or more IP Multicast group addresses can be mapped to a MAC group address. Forwarding, based on the MAC group address, can result in an IP Multicast stream being forwarded to ports that have no receiver for the stream.
- IP Group Address--Based on the destination IP address of the IP packet (*,G).
- Source Specific IP Group Address--Based on both the destination IP address and the source IP address of the IP packet (S,G).
By selecting the forwarding mode, you can define the method used by hardware to identify Multicast flow by one of the following options: MAC Group Address, IP Group Address, or Source Specific IP Group Address.
(S,G) is supported by IGMPv3 and MLDv2, while IGMPv1/2 and MLDv1 support only (*.G), which is just the group ID.
The switch supports a maximum of 256 static and dynamic Multicast group addresses.
To enable Multicast filtering, and select the forwarding method:
- Click Multicast> Properties. The Properties page opens.
- Enter the parameters.
- Bridge Multicast Filtering Status--Select to enable filtering.
- VLAN ID--Select the VLAN ID to set its forwarding method.
- Forwarding Method for IPv6--Set one of the following forwarding methods for IPv6 addresses: MAC Group Address, IP Group Address, or Source Specific IP Group Address.
- Forwarding Method for IPv4--Set one of the following forwarding methods for IPv4 addresses: MAC Group Address, IP Group Address, or Source Specific IP Group Address.
- Click Apply. The Running Configuration file is updated..