A.C-RP routers periodically send announcement messages in multicast mode

B.BSR is generated through an automatic election process between C-BSR

C.During C-BSR election, the priority is first compared, and then the IP address of the bootstrap message is compared

D.After receiving the C-RP announcement message, the BSR calculates the RP to be selected by each multicast group according to the relationship between the RP and the multicast group, and multicasts the calculation result

A.Configuration BPDUs are usually only sent periodically by the root bridge, and TCNBPDUs may be sent by other bridges except the root bridge.

B.AIternate port will neither send configuration BPDU nor TCNBPDU

C.Configure BPDUs to be sent only from the designated port, and TCNBPDUs to be sent only from the root port

D.The configuration BPDU is usually received only from the root port, and the TCNBPDU is only received from the designated port

A.All operations have become non-atomic, greatly improving the effectiveness of protocol message interaction

B.Provide a more reliable security mechanism and make the application more secure

C.Added GETBULK REQUEST operation, which can request large quantities of data at once

D.Provide richer error codes, which can express errors more accurately and facilitate problem location

A.When the port is in Listening state and Learning state, if the port role is changed to Alternate port, the port state will directly change to Blocking

B.When the port is in the Learning state, it starts to learn the MAC address, but does not forward data

C.When the port is in the Listening state, it will receive configuration BPDUs and perform calculations, but not send configuration BPDUs

D.No matter what role the port finally determines, the time spent in the Listening state and the Learning state is a ForwardDelay duration

A.Both IGMP & IGMP Snooping can be configured in the same VLAN

B.Using the iIGMP Snooping function on the Layer 2 device can establish and maintain multicast forwarding entries at the data link layer, so that multicast data can be forwarded normally at the data link layer

C.Port quick leave means that when the switch leaves the IGMP Leave message, it directly deletes the port from the outgoing port list of the corresponding forwarding entry

D.The unknown multicast group dropping function can be enabled on the switch. When the switch receives unknown multicast data packets, it will only forward to its router port and not broadcast in the VLAN.