Data Communications and Networking
Two Communication Models - ANS-Client/Server (Email)
-client host requests, receives service from always-on server
Peer-Peer Model (Skype)
-Minimal (or no) use of dedicated servers
How many layers does the OSI Model have? - ANS-7
Protocol (*Exam Question*) - ANS-A protocol defines data representation (packet formats), the
meaning of data at specific fields within the packet or within certain states, state transitions, and
interaction rules for participating nodes
What is Hamming distance? - ANS-The number of bits which are different between two code
words
Internet Protocol Stack (Application,Transport,Network,Link,Physical) - ANS-Application:
Supporting network applications (FTP,HTTP,SMTP)
Transport: Process-process data transfer (UDP,TCP)
Network: routing of data-grams from source to destination (IP, routing protocols)
Link: data transfer between neighboring and network elements (PPP, Ethernet)
Physical: Bits "on the wire"
Transmission Delay - ANS-Rate at which we can change the electrical and optical signals on the
medium
Major Transmission Media Types - ANS--UTP & Fiber
-Wi-fi, CDMA, GSM
-Coax
Fiber vs. Copper Pros (*Exam Question*) - ANS-Copper
-Less skill to install
-More resilient to damage
-Less costly physical connectivity
-Less costly components
Fiber
, -Higher bandwidth
-Less attenuation (Further transmission)
-Not affected by power surges, Electromagnetic radiation
-More secure
Bandwidth - ANS-Frequency transmitted without significant attenuation
Baud Rate - ANS-Symbols transmitted per second
Propagation Delay - ANS-2*10^8
-Velocity of bits through medium
Packet - ANS-A data structure with a header and a date portion (preamble)
-header contains protocol info
-data portions refers to what is being carried
Which layer contains MAC (Media Access Control) - ANS-Layer 2.
What does CSMA/CD stand for? - ANS-Carrier Sense Multiple Access, Collision Detect
What is a "frame"? - ANS-used to describe unique messages at the physical and data link layer
(layers 1 and 2)
Transport Layer (L4) - ANS-Responsible for process to process delivery of "messages"
-Ports come in to play at this layer
-TCP & UDP live here
Session Layer (L5) - ANS-Responsible for dialog control and synchronization
Application Layer (L7) - ANS-Client software lives here
How can we succeed at organizing the structure of the network? - ANS-By breaking up
functions into layers
Physical Layer (L1) - ANS--Moves bits between connected systems
-Defines everything physical, E.g. --> # of wires, Electrical levels, twists in cables, distances
Client/Server Communication Model - ANS--One device is making requests from another
-The client is not in control
-Clients don't talk to each other, they talk in star topology through the server
Peer-Peer Communication Model - ANS-All nodes are equal, share equal responsibilities
Two Communication Models - ANS-Client/Server (Email)
-client host requests, receives service from always-on server
Peer-Peer Model (Skype)
-Minimal (or no) use of dedicated servers
How many layers does the OSI Model have? - ANS-7
Protocol (*Exam Question*) - ANS-A protocol defines data representation (packet formats), the
meaning of data at specific fields within the packet or within certain states, state transitions, and
interaction rules for participating nodes
What is Hamming distance? - ANS-The number of bits which are different between two code
words
Internet Protocol Stack (Application,Transport,Network,Link,Physical) - ANS-Application:
Supporting network applications (FTP,HTTP,SMTP)
Transport: Process-process data transfer (UDP,TCP)
Network: routing of data-grams from source to destination (IP, routing protocols)
Link: data transfer between neighboring and network elements (PPP, Ethernet)
Physical: Bits "on the wire"
Transmission Delay - ANS-Rate at which we can change the electrical and optical signals on the
medium
Major Transmission Media Types - ANS--UTP & Fiber
-Wi-fi, CDMA, GSM
-Coax
Fiber vs. Copper Pros (*Exam Question*) - ANS-Copper
-Less skill to install
-More resilient to damage
-Less costly physical connectivity
-Less costly components
Fiber
, -Higher bandwidth
-Less attenuation (Further transmission)
-Not affected by power surges, Electromagnetic radiation
-More secure
Bandwidth - ANS-Frequency transmitted without significant attenuation
Baud Rate - ANS-Symbols transmitted per second
Propagation Delay - ANS-2*10^8
-Velocity of bits through medium
Packet - ANS-A data structure with a header and a date portion (preamble)
-header contains protocol info
-data portions refers to what is being carried
Which layer contains MAC (Media Access Control) - ANS-Layer 2.
What does CSMA/CD stand for? - ANS-Carrier Sense Multiple Access, Collision Detect
What is a "frame"? - ANS-used to describe unique messages at the physical and data link layer
(layers 1 and 2)
Transport Layer (L4) - ANS-Responsible for process to process delivery of "messages"
-Ports come in to play at this layer
-TCP & UDP live here
Session Layer (L5) - ANS-Responsible for dialog control and synchronization
Application Layer (L7) - ANS-Client software lives here
How can we succeed at organizing the structure of the network? - ANS-By breaking up
functions into layers
Physical Layer (L1) - ANS--Moves bits between connected systems
-Defines everything physical, E.g. --> # of wires, Electrical levels, twists in cables, distances
Client/Server Communication Model - ANS--One device is making requests from another
-The client is not in control
-Clients don't talk to each other, they talk in star topology through the server
Peer-Peer Communication Model - ANS-All nodes are equal, share equal responsibilities
