4.19. Consider the procedure to maintain the spanning tree. For a bridge B with three ports x,y,z and root bridge ID = w, rpc = p. Assume port x is an R port, port y is a D port of a LAN1, port z is blocked and connected to a LAN2. What actions will be taken by bridge B if the hello BPDUs suppose to be received from port z are lost for a long time (a timeout event) ?
A. (a) Port z is selected as a new R port.
B. (b) Port z is selected as a D port.
C. (c) A BPDU with (with root bridge ID = w, rpc =p) is forwarded to port x.
D. (d) A BPDU (with root bridge ID = w, rpc =p) is forwarded to port y.
E. (e) A BPDU (with root bridge ID = w, rpc =p) is forwarded to port z.
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4.20 Consider the procedure to maintain the spanning tree. For a bridge B with three ports x,y,z and root bridge ID = w, rpc = p. Assume port x is an R port, port y is a D port, port z is blocked and connected to a LAN m. What will happen if the hello BPDUs suppose to be received from port x are lost for a long time (a timeout event) ?
A. (a) Bridge B will consider itself as a new root bridge and start the procedure to construct the spanning tree.
B. (b) port y is selected as a new R port.
C. (c) Ports x,y,z are selected as D port.
D. (d) A BPDU with (with root bridge ID = B, rpc =0) is forwarded to ports x, y, z.
E. (e) A BPDU (with root bridge ID = w, rpc =q) is forwarded to port z.
4.21 Consider the procedure to maintain the spanning tree. For a bridge B with three ports x,y,z and root bridge ID = w, rpc = p. Assume port x is an R port, port y is a D port, port z is blocked and connected to a LAN m. Which of the following statements are correct for the transmission of TCN (topology change notification) BDPU ?
A. (a) A TCN BPDU will be sent to port x if state of port z is changed to forwarding state.
B. (b) A TCN BPDU will be sent to port x if state of port y is changed to blocked state.
C. (c) A TCN BPDU will be sent to port y if state of port z is changed to forwarding state.
D. (d) A TCN BPDU will be sent to port z if state of port y is changed to blocked state.
4.22 Consider the procedure to maintain the spanning tree of a BLAN. Which of the following statements are correct for the transmission of TCN (topology change notification) BDPU ?
A. (a) A bridge will send a TCN BDPU to the root bridge if one of its port changed state (from blocked state to forwarding state, or vise versa)
B. (b) The TCN BPDU will be delivered to the root bridge along the spanning tree.
C. (c) The TCN BPDU will be delivered to the root bridge along multiple communication paths.
D. (d) The TCN BPDU is delivered via a reliable, hop-by-hop method.
E. (e) The TCN BPDU is delivered via a best effort method.
In IEEE 802.11 Wireless LAN, the signals are propagated through which media ?
A. (a) Coaxial cable
B. (b) Optical fiber
C. (c) Twisted pair
D. (d) Space (air)
E. (e) Power Line
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