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Across 6. The data link layer was designed to deal with ensuring the physical layer can recover from errors that might happen and to deal with different connecting mediums. Basically it prepares (encapsulates) data so that it can be transmitted over whatever physical means are necessary (radio waves, fiber-optic cable, copper)

Down 1. Responsible for guaranteeing that data is exchanged in a way that is comprehensible between both parties. In some services that use a form of encryption, the encryption happens at the presentation layer 2. Responsible for dialogue control between two computers. Basically it establishes, manages and terminates all connections that happen between the computers. 3. This layer defines the physical specifications of the devices and what needs to be done in order for the information to be transmitted over the selected medium. For a WiFi connection, this is a radio signal; for a fiber connection it's the light being sent; or for a copper connection the electronic signal being sent on the wire 4. This layer is responsible for the addressing part of the connection. Not only on ensuring that each address is unique on the network, but also on making sure that whatever path is available (whether a good or a bad one), it always delivers the information where it needs to go, and that our information will be sent from hop to hop until it reaches its final destination. 5. Provides transparent transfer of data between computers, providing reliable data transfer services to the upper layers. This means that it is responsible for assembling all data in smaller portions that can be carried reliably on a data network. If a packet is lost or not received, it is the transport layer's job to make sure that that single packet is retransmitted and then reassembled in the correct order.