What are differences between the multicast and unicast transmission modes for S series switches

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Differences between the multicast and unicast transmission modes
- In unicast transmission mode, a source sends an independent data packet to each host that requires data. In this mode, the amount of data transmitted on a network is proportional to the number of users who require the data. If a large number of users require the same data, the source must send many copies of the data to these users, consuming high bandwidth on the source and network.
- Multicast is a point-to-multipoint (P2MP) data transmission mode. The source sends only one copy of data, and all the hosts that require the data can receive the same data. Other hosts on the network cannot receive the data. In multicast mode, data starts to be copied and distributed on the network node as far from the source as possible. Therefore, the amount of data and network resource consumption will not increase greatly when the number of receivers increases.

Disadvantages of multicast transmission
- Compared with the unicast mode, the multicast mode has no error correction mechanism, but some fault tolerance mechanisms can be adopted.
- Although multicast transmission is supported by existing networks, features such as customer authentication and QoS are not well supported.

Other related questions:
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.

Differences between the three multicast-related routing tables on an S series switch
On an S series switch, the following tables are generally searched for MFIB entries: PIM routing table, multicast routing table, and multicast. - A PIM routing table contains entries generated by PIM at the protocol layer. You can view source and group information learned by PIM at the protocol layer in a PIM routing table. - A multicast routing table associates the protocol layer with the MFIB module. Entries at the protocol layer are stored in a multicast routing table before being delivered. Entries stored in the MFIB module must be the same as those stored in the multicast routing table. - A multicast forwarding table contains entries stored in the MFIB module. The MFIB module stores forwarding entries delivered from the protocol layer in the multicast forwarding table. The forwarding entries are then delivered to the multicast module of a switch. Normally, entries stored in the multicast forwarding table must be the same as those stored in the multicast routing table.

Must unicast routes be reachable when the multicast function is configured on an S series switch
Protocol independent multicast (PIM) uses routes in the unicast routing table. Therefore, PIM depends on a unicast routing protocol and can work only when unicast routes are reachable.

What are the differences between 802.1X and DOT1X on S series switch?
802.1X and DOT1X provide the same function.

What is the difference between the BPDU packet transparent transmission modes of the bridges on AR routers in different forms

Difference between the BPDU packet transparent transmission modes of the bridges on AR routers in different forms:
The bridges on AR routers in all forms do not transparently transmit BPDU packets. Therefore, there is no difference.

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