Network+™: Study Guide, Fourth Edition

2.9. Answers to Review Questions

1. B. Of the layers listed, the only OSI layer that is responsible for reliable end-to-end communications is the Transport layer. The Network layer is responsible for logical network addresses, the Session layer is responsible for opening sessions and maintaining session information, and the Presentation layer is responsible for how data "looks" to the upper layer(s).

2. D. Of the OSI model layers listed, the Network layer is the only one that is responsible for routing information because it contains information for logical network addressing.

3. A. The Physical layer, as its name suggests, is the layer responsible for placing electrical transitions on the physical media. The other layers are all upper layers.

4. D. The 802.5 ...