Chapter 2 Flash Cards - OSI Model
What mnemonic is used to remember the order and names of the layers of the OSI model? Name the 7 layers.
Please Do Not Throw Sausage Pizza Away.Physical, Data Link, Network, Transport, Session, Presentation, Application
What are the benefits of a layered system? (i.e. OSI,TCP/IP)
- Less complex2. Standard interfaces3. Easier to learn4. Easier to develop5. Multivendor interoperability6. Modular engineering
Define: Adjacent-layer interaction
On a single computer, one layer provides a service to a higher layer. The software or hardware that implements the higher layer requests that the next lower level preform the needed function.
Define: Decapsulation
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.
Define: Encapsulation
The placement of data from a higher-layer protocol behind the header (and in some cases, between a header and trailer) of the next-lower-layer protocol.
Define: Frame
Data Link layer (LH, LT, Ethernet, PPP) header and trailer around Data, L2PDU.
Define: Networking Model
A generic term referring to any set of protocols and standards collected into a comprehensive grouping that, when followed bt the devices in a network, allows the devices to communicate.
Define: Packet
Network layer (IP) header and data, L3PDU.
Define: Protocol Data Unit (PDU)
An OSI term to refer generically to a grouping of information by a particular layer of the OSI model. More specifically, an LxPDU would imply the data and headers as defined by Layer x.
Define: Same-Layer Interaction
The two computers use a protocol to communicate with the same layer on another computer. The protocol defined by each layer uses a header that is transmitted between the computers, to communicate what each computer wants to do.
Define: Segment
Transport layer (TCP, UDP) header and Data, L4PDU. In Ethernet, it is either a single Ethernet cable or a single collision domain.
OSI Layer 1: Provide functional description of the above OSI Layer.
Physical Layer. Defines electrical, optical, cabling, connectors, and procedure details required for transmitting bits, represented as some form of energy passing over a physical medium.
OSI Layer 2: Provide functional description of the above OSI Layer.
Data Link Layer. Formats data into frames appropriate for transmission. Define when the medium can be used. Defines means for error detection.
OSI Layer 3: Provide functional description of the above OSI Layer.
Network Layer. Local addressing, routing, path determination.
OSI Layer 4: Provide functional description of the above OSI Layer.
Transport Layer. Flow control, error recovery, segmentation, connection establishment and termination.
