Question

The original commercial version of Ethernet supported 10 Mbps bandwidth; the version introduced in the early 1990s supports 100 Mbps; and in 1998, Gigabit Ethernet was introduced. All versions use the same data frame formats, with the same maximum PDU sizes, so they can interoperate freely. Given this information and what you know of layered technologies, which of the following statements is true? (Choose all that apply.)
a. Ethernet works at the Data Link and Physical layers of the OSI model, and upgrades to newer, faster versions of Ethernet can be made by changing only the components that work at these layers.b. Ethernet spans several layers and requires a new protocol stack to upgrade to new versions.c. Changes in technology at one layer of the OSI model don’t usually affect the operation of other layers.d. Ethernet isn’t considered a scalable technology.

Answer 1

Answer: a) and c).

Explanation:

• Ethernet is a Layer 2 and also Layer 1 Technology (this layer defines the technical details of cabling and connectors), so any upgrade to a newer, faster version (like 100G Ethernet) will be possible changing only the components operating at these layers, without changing anything in the higher layers like IP and TCP, for instance.

• This is a direct consequence of the OSI layer model foundations, that say basically that each each layer is independent from the others, so the piece of software pertaining to one layer, only interacts with his layer peer in the destination machine.
• So, any changes to the technology used in one of the layers, don't usually affect the operation of the other layers.