In HDLC (High-Level Data Link Control), which frame type is used to carry user application data along with piggybacked flow/error control ACKs?
HDLC classifies frames into I-frames (carry user network-layer data), S-frames (control flow/errors like RR, RNR, REJ), and U-frames (link initialization/disconnect).
Which access method divides a satellite channel's frequency spectrum into narrow bands, assigning a dedicated band to each ground station?
FDMA splits the frequency band into individual channels assigned permanently or dynamically to different transmitting stations.
What type of address does a Layer-2 transparent switch use to populate its MAC address forwarding table (CAM table)?
Transparent switches learn topology dynamically by inspecting the Source MAC address of incoming frames on each physical port.
What happens when a switch receives a unicast frame whose destination MAC address does not exist in its MAC address table?
When the destination MAC is unknown, a switch performs unknown unicast flooding, transmitting the frame to all other active ports in the broadcast domain.
What is the network address for a host with IP address 192.168.10.138 and subnet mask 255.255.255.192?
The mask is /26, giving subnet blocks of 64 addresses. The address 192.168.10.138 belongs to the 192.168.10.128/26 subnet, so the network address is 192.168.10.128. It is not listed in A-C, so None of the above is correct.