chapter 2 Flashcards
data communication
What is a network?
A combination of hardware and software that sends data from one location to another.
What does the hardware of a network consist of?
The physical equipment that carries signals from one point of the network to another.
What does the software of a network consist of?
Instructions set that make possible the services that we expect from a network.
What is the OSI model?
A model for understanding and designing a network architecture that is flexible, robust, and interoperable.
How many layers does the OSI model consist of?
Seven separate but related layers.
What is the function of Layer 3 in the OSI model?
Uses services provided by Layer 2 and provides services for Layer 4.
What are peer-to-peer processes?
Processes on each machine that communicate at a given layer.
True or False: Communication at the physical layer is direct.
True.
What is the role of interfaces between layers in the OSI model?
To pass data and network information down through the layers of the sending device and back up through the layers of the receiving device.
Which layers of the OSI model are considered network support layers?
- Layer 1 (Physical)
- Layer 2 (Data Link)
- Layer 3 (Network)
Which layers of the OSI model are considered user support layers?
- Layer 5 (Session)
- Layer 6 (Presentation)
- Layer 7 (Application)
What is the function of Layer 4 (Transport Layer)?
Links the two subgroups and ensures that what the lower layers have transmitted is in a form that the upper layer can use.
What services does the Application Layer (Layer 7) provide?
- Network virtual terminal
- File transfer, access, and management
- Mail services
- Directory services
What is the responsibility of the Presentation Layer (Layer 6)?
Concerned with the syntax and semantics of information exchange between two systems.
Fill in the blank: The process of transforming original information to another form for transmission is called _______.
[Encryption]
What does the Session Layer (Layer 5) control?
Establishes, maintains, and synchronizes the interaction among communicating systems.
What is the main responsibility of the Transport Layer (Layer 4)?
Process-to-process delivery of the entire message.
What does flow control in the Transport Layer prevent?
The sender from overwhelming the receiver with data.
What is logical addressing in the Network Layer (Layer 3)?
Used to uniquely identify each host on the network.
What is the function of the Data Link Layer (Layer 2)?
Transforms the physical layer to a reliable link.
What are the responsibilities of the Data Link Layer?
- Framing
- Physical addressing
- Flow control
- Error control
- Access control
What does the Physical Layer (Layer 1) coordinate?
Functions required to carry a bit stream over a physical medium.
What is the representation of bits at the Physical Layer?
A stream of bits (0’s and 1’s) with no interpretation.
What are the types of transmission modes defined by the Physical Layer?
- Simplex
- Half duplex
- Full duplex
