網絡：练习题

• a.Transport layer
• b.Link layer
• c.Application layer
• d.Network layer

• a.To ensure that only devices with authorised MAC addresses can connect to the access point.
• b.To encrypt data packets using the WPA2 standard before they are transmitted wirelessly.
• c.To detect when a collision has occurred and immediately retransmit the lost packet.
• d.To prevent data collisions by checking the medium and using a 'Request to Send/Clear to Send' handshake.

• a.The central switch acts as a router, examining the Network layer header to send packets only to the destination node.
• b.Data is passed in a sequential loop from one node to the next until it reaches the destination.
• c.Data is physically routed through a central point but logically behaves as if all nodes are connected to a single shared cable, broadcasting to all nodes.
• d.The switch creates a dedicated point-to-point circuit for every transmission, preventing all collisions.

• a.To forward packets within the same local area network using MAC addresses.
• b.To translate private IP addresses into a single public IP address for internet access.
• c.To assign dynamic IP addresses to devices as they join the network.
• d.To connect networks that use different protocols by performing protocol translation.

• a.6 bits
• b.4 bits
• c.3 bits
• d.5 bits

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。