Chapter 1 Flashcards
Chapter 1 Review
When 2 computers use a protocol to communicate with the same layer on another computer. The protocol defines a header that communicates what each computer wants to do.
Same-layer interaction on different computers.
On a single computer, one lower layer provides a service to the layer just above. The software or hardware that implements the higher layer requests that the next lower layer perform the needed function.
Adjacent-layer interaction on the same computer.
On a computer that receives data over a network, the process in which the device interprets the lower-layer headers and when finished with each header, removes the header, revealing the next-higher-layer PDU.
de-encapsulation
The process of putting headers (and sometimes trailers) around some data
encapsulation
A term referring to a data-link header and trailer, plus the data encapsulated between the header and trailer.
frame
A logical grouping of bytes that includes the network layer header and encapsulated data, but specifically does not include any headers and trailers below the network layer.
packet
The communication between two networking devices for the purposes of the functions defined at a particular layer of a networking model, with that communication happening by using a header defined by that layer of the model. The two devices set values in the header, send the header and encapsulated data, with the receiving devices interpreting the header to decide what action to take.
same-layer interaction
In TCP, a term used to describe a TCP header and its encapsulated data (also called an L4PDU). Also in TCP, the process of accepting a large chunk of data from the application layer and breaking it into smaller pieces that fit into TCP segments. In Ethernet, a segment is either a single Ethernet cable or a single collision domain (no matter how many cables are used).
segment
The process by which a TCP/IP host sends data can be viewed as a five-step process. The first four steps relate to the encapsulation performed by the four TCP/IP layers, and the last step is the actual physical transmission of the data by the host. In fact, if you use the five-layer TCP/IP model, one step corresponds to the role of each layer. The steps are summarized in the following list:
Step 1. Create and encapsulate the application data with any required application layer headers. For example, the HTTP OK message can be returned in an HTTP header, followed by part of the contents of a web page.
Step 2. Encapsulate the data supplied by the application layer inside a transport layer header. For end-user applications, a TCP or UDP header is typically used.
Step 3. Encapsulate the data supplied by the transport layer inside a network layer (IP) header. IP defines the IP addresses that uniquely identify each computer.
Step 4. Encapsulate the data supplied by the network layer inside a data-link layer header and trailer. This layer uses both a header and a trailer.
Step 5. Transmit the bits. The physical layer encodes a signal onto the medium to transmit the frame.
____________ is used to refer to any message defined by a protocol.
PDU or Protocol Data Unit
The __________ model defines how devices should transmit data between them and enables communication over networks and large distances. The model represents how data is exchanged and organized over networks.
TCP\IP
List each of the Layers in order from top to bottom, of the TCP\IP model:
Application
Transport
Network
Data Link
Physical
List each of the Layers in order from top to bottom, of the OSI model:
Application
Presentation
Session
Transport
Network
Data Link
Physical
The term _________ refers to any device, regardless of size or power, that has an IP address and connects to any TCP/IP network.
IP host
process of forwarding the IP packet is called IP ____________
Routing
