Network Layer

4 Layer Internet Model

• Application Layer
  • Bi-directional reliable byte stream between two applications, using application-specific semantics (e.g. Hypertext Transfer Protocol, BitTorrent, SSH, FTP).
• Transport Layer
  • TCP and UDP
  • Guarantees correct, in-order delivery of data end-to-end. TCP Congestion Control
• Network Layer
  • IP and Routing
  • No need to concern how packets are sent via link layer
  • Delivers datagrams end-to-end. Best-effort delivery, no guarantees. Must be used with the Internet Protocol.
• Link Layer
  • Ethernet or WiFi
  • Delivers data over a single link between an end host and router, or between routers

7 Layer OSI Model

1. Physical Layer
2. Data Link Layer
   1. Frame
3. Network Layer
   1. Packet
4. Transport Layer
   1. Segment
5. Session Layer
6. Presentation Layer
7. Application Layer