Tema 1.2 - Ethernet

Regarding the frame extension mechanism, it is used:

• In all versions of Ethernet, when the frame size is greater than 512 bytes.

• In all versions of Ethernet, when the frame size is smaller than 512 bytes.

• In Gigabit Ethernet, when the frame size is greater than 512 bytes.

• In Gigabit Ethernet, when the frame size is smaller than 512 bytes.

For Frame Bursting, suppose that we send 10 consecutive frames sized 64 bytes. Where does Carrier Extension take place?

• Before the first frame.

• After the first frame.

• After the last frame.

• In this case Carrier Extension is not required since we surpass the minimum size required to detect collisions (10x64=640 bytes).

In Gigabit Ethernet, the Frame Bursting mechanism is used to:

• Avoid that a station has to wait for too long before transmitting.

• Guarantee that a station with more high-priority frames is able to transmit first.

• Improve link utilization if, in general, sent frames are prone to be small.

• Improve link utilization if, in general, sent frames are typically large.

In a Gigabit Ethernet LAN at home or small businesses, the most widely used standard is:

• 1000Base-LX

• 1000Base-CX

• 1000Base-TX

• 1000Base-T

Transmitting energy using Power over Ethernet (PoE) involves:

• 1 copper pair

• 2 copper pairs

• 4 copper pairs

• 2 or 4 copper pairs

When transmitting using fiber optics, the best fiber technology is:

• Single mode fiber.

• Multi-mode – graded index fiber.

• Multi-mode – step index fiber.

• None of the former.

In Ethernet, jumbo frames are frames with a payload that is:

• Greater than 1500 bytes, and up to 9000 bytes.

• Greater than 64 bytes, and up to 8000 bytes.

• Greater than 512 bytes, and up to 9000 bytes.

• Greater than 2000 bytes, and up to 8000 bytes.

Link aggregation is a concept that emerges to:

• Provide a solution to allow connecting switches to each another.

• Provide a solution to increase the speed of a single cable.

• Provide a solution for backbone connections requiring greater capacity without upgrading to a faster technology.

• All the former answers are true.

Which of the following characteristics is not common when comparing Ethernet, Fast Ethernet and Gigabit Ethernet?

• CSMA/CD support.

• Minimum/maximum frame size.

• Possibility to user fiber optics.

• Times associated with the slot-time/Inter-frame gap.

Regarding the 10-Gigabit standard:

• It supports half-duplex mode.

• It adopts jumbo frames.

• It supports UTP cables.

• It is not compatible with SONET.