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Computers A and B are on the same VLAN and are separated by two switches as shown in the exhibit. Computer A sends a frame to Computer B. Which of the following best describes the composition of the frame as it travels from A to B?

1) The frame will contain the source and destination MAC addresses
2) The frame will contain the source and destination IP addresses
3) The frame will contain the source and destination port numbers
4) The frame will contain the source and destination VLAN IDs

1 Answer

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Final answer:

A frame sent by Computer A to Computer B on the same VLAN will contain the source and destination MAC addresses. IP addresses and port numbers are not part of an Ethernet frame and are used at higher OSI layers. VLAN IDs are only included if VLAN tagging like 802.1Q is in use.

Step-by-step explanation:

When Computer A sends a frame to Computer B on the same VLAN and the frame has to pass through two switches, the frame will contain specific information to reach its destination correctly. As the devices are on the same VLAN and the transmission occurs at Layer 2 of the OSI model, the frame will for sure contain the source and destination MAC addresses. These addresses are necessary for switches to forward the frame between devices within the same network segment or VLAN.

While IP addresses (option 2) and port numbers (option 3) are crucial for routing packets at the network layer and above, they are not used by Ethernet frames at the data link layer. Therefore, the frame won't contain port numbers, as they are part of the TCP/UDP header, not the Ethernet frame itself. Regarding the VLAN ID option (option 4), when on the same VLAN, the frames do not typically have a VLAN ID; however, if VLAN tagging is in use like in 802.1Q, then the frames would include the VLAN ID. This tagging is utilized to keep traffic separated at the switch level when frames pass through trunk ports.

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