| Layer 1: The Physical Layer The Physical Layer describes physical properties of the media, such as the electrical properties and interpretation of exchanged signals. |
Cable | Cable |
| Layer 2: The Data Link Layer The Datalink Layer describes the logical organization of data bits transmitted on a particular medium, for example the logical addressing of Ethernet packets. |
Ethernet / MAC | Bridge or Switch |
| Layer 3: The Network Layer The Network Layer describes how a series of exchanges over various data links can deliver data between any two nodes in a network; basically describing how packets get routed through the 'net. |
IP | Router or Layer 3 Switch |
| Layer 4: The Transport Layer The Transport Layer describes the quality and nature of the data delivery. |
TCP | "Layer 4" Switch |
| Layer 5: The Session Layer The Session Layer describes the organization of data sequences larger than the packets handled by the lower layers. Basically, its the job of the Session Layer to fix what the other layers have screwed up. |
winsock / DHCP | N/A |
| Layer 6: The Presentation Layer The Presentation Layer describes the syntax of data being transferred for communication with dissimilar systems. |
. | N/A |
| Layer 7: The Application Layer The Application Layer describes how real work actually gets done; its the reason we do things in the first place. |
Firewall | N/A |