Can an S series switch accurately forward multicast data packets if only Layer 3 multicast is configured

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For S series switches, Layer 3 multicast protocols can identify only Layer 3 VLANIF interfaces. If only Layer 3 multicast is configured and Layer 2 multicast is not enabled, multicast data is replicated on a VLANIF interface and broadcast in the corresponding VLAN, but cannot be forwarded to an accurate physical interface.
When Layer 2 multicast is enabled in the VLAN corresponding to the VLANIF interface, multicast data can be accurately forwarded through a Layer 2 interface.

Other related questions:
When Layer 3 multicast forwarding fails on an S series switch, how can I determine whether the reason is that the TTL value of multicast data packet is 1
All S series switches that support Layer 3 multicast can generate multicast forwarding entries for multicast data packets with the TTL value of 1, but cannot forward such multicast data packets. Use either of the following methods to check whether the TTL value of multicast data packets is 1: - Obtain packet headers by capturing incoming multicast packets on the uplink interface. Check whether the TTL value of multicast data packets is 1. - Run the debugging mfib packet command in the user view to enable debugging of Layer 3 multicast packets, and then run the reset multicast forwarding-table group-address command to delete all multicast forwarding entries. Check whether "TTL=1" is displayed in the debugging information.

Why is no Layer 3 multicast forwarding entry generated on S series switches after users order multicast programs
The possible causes are as follows: - No RP is configured on the PIM-SM network. In this case, configure static or dynamic RP. - The route to the multicast source or RP is unreachable. In this case, configure a unicast routing protocol to enable the switch to learn the routes to the multicast source or RP.

Do S series switches support the Layer 3 multicast function
To achieve multicast forwarding of video services on Layer 3 networks, you need to configure the Layer 3 multicast function on switches. The Layer 3 multicast function requires two multicast protocols as follows: - Internet Group Management Protocol (IGMP): It is used to establish and maintain multicast group memberships between receiver hosts and directly connected multicast routers. - Protocol Independent Multicast (PIM): It is used to obtain multicast requirements of receiver hosts, generate multicast routing entries, and set up multicast forwarding paths. IGMP and PIM are supported by Huawei S series modular switches, and Sx7 series fixed switches including the S3700EI, S3700HI, S5700EI, S5710EI, S5720EI, S5700HI, S5710HI, S5720SI, S5720S-SI, S5720HI, S6700EI, S6720EI and S6720S-EI.

Difference between forwarding modes of Layer 2 multicast on an S series switch
After Layer 2 multicast is enabled on an S series switch, the switch maintains a Layer 2 multicast forwarding table. When receiving a multicast packet, the switch matches the multicast address of the packet with multicast forwarding entries to determine the outbound interface. Whether the switch determines the outbound interface based on the multicast IP address or multicast MAC address depends on the configured Layer 2 multicast forwarding mode. Multiple multicast IP addresses may be mapped to one MAC address. If multicast data is forwarded based on the MAC address, multicast data may be sent to the users who do not order the multicast data. MAC address-based multicast forwarding can improve specifications in certain scenarios. Different models support different Layer 2 multicast forwarding modes: - The S1720, S2700SI, S2710SI, S2700EI, S2720, S2750EI, S5700S-LI, and S5700LI support only MAC address-based multicast forwarding. - The S3700SI and S5710-C-LI support only IP address-based multicast forwarding. - The S5700SI supports only IP address-based multicast forwarding in V200R002 and earlier versions, and supports MAC address-based and IP address-based forwarding modes starting from V200R003. - The S3700EI, S3700HI, S5710-X-LI, S5720S-SI, S5720SI, S5700EI, S5710EI, S5720EI, S5700HI, S5710HI, S5720HI, S6700EI, S6720EI, S7700, S9700, S12700, S9300, and E600 support MAC address-based and IP address-based forwarding modes.

Default Layer 2 multicast forwarding mode on an S series switch
For S series switches excluding the S1700, after Layer 2 multicast is enabled, the S1720, S2710SI, S2700SI, S2700EI, S2720EI, S2750EI, S5700LI, and S5700S-LI (S5700S-28X-LI-AC and S5700S-52X-LI-AC) forward multicast data based on MAC addresses, and other models forward multicast data based on IP addresses by default.

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