What are the advantages of protocol layering?
Protocol layering provides a way to simplify a complex problem by dividing it into a number of smaller functions. Each layer performs a specific function.
What are the four layers of technology used in the TCP/IP protocol suite?
Application Layer, Transport Layer, Internet Layer, and Link Layer
What is Data Encapsulation?
Data encapsulation is the mechanism by which each layer in the protocol stack adds information to the application-generated data. That information is intended to be interpreted by an entity of the same layer in a remote device, in such a way that the data is properly processed and delivered to the intended receiver and to the right application.
Describe the Application layer of the TCP/IP Suite
The Application layer packages the data in such a way that it can be properly interpreted at the remote end.
Describe the Transport Layer of the TCP/IP Suite
The Transport Layer breaks the information into smaller segments that can be transported from end to end and passes them down to the Internet layer.
Comprised of two main protocols: TCP and UDP
Describe the Internet Layer of the TCP/IP Suite
The Internet Layer provides end-to-end addressing and carries the data packets from source to destination.
Universal and consistent forwarding service across a TCP/IP network
Describe the Link Layer of the TCP/IP Suite
The Link Layer has to do with local hop-by-bop addressing, data framing, and medium access control; it assumes there is a mechanism in place to transmit signals from one device to the next.
Defines the actual interfaces between nodes
Ethernet
Define a Layer-2 Broadcast Domain
- All hosts are connected to the same Local Area Network (LAN)
- There may be several LAN segments interconnected by switches which make forwarding decisions based on MAC addresses
- All hosts obtain IP Addresses with the same prefix, also known as an IP Subnet, which identifies the layer-2 domain.
Define a Layer-3 Domain
- There may be two or more layer-2 broadcast domains (subnets) interconnected by routers, which make forwarding decisions based upon IP Addresses
- When an IP packet needs to be sent to a host in a different subnet it is first sent to a router.
What are functions of the control plane?
- Enable routers to exchange control messages and to agree on the best way to forward packets
- Establish the necessary routing paths and/or tunnels required to deliver packets from source to destination
What are functions of the Data Plane?
- Use forwarding tables created by control-plane functions to properly forward every data packet towards its intended destination.
What occurs when a packet travels from an upper layer to a lower layer?
The data is encapsulated with a new header
What occurs when a packet travels from a lower layer to the upper layer?
A layer-specific header is removed from the data
What happens to the link-layer header at each router?
A new layer-2 header/link-layer header is created
