CS 6250 Quiz 1 (All Quizzes) Latest Update | Verified
Questions and Correct Answers | Complete Study Guide –
Georgia Institute of Technology
2026/202
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7 | GRADED A+ | 100 out of 100
Question:
How did LIcklider and his team in the early 1960s experiment with a precursor to the Internet?
Answer
Connecting two computers over a dial-up telephone line
Question:
What is the DNS designed to do primarily
Answer
Translate domain names into IP addresses
Question:
What is the architecture design of the internet protol stack based on?
Answer
Layers
Question:
Both the data link and transport layer provide error correction
Answer
True
Question:
What allows for communication between the application layer and transport layer
Answer
Socket
Question:
Whis protocol belongs to application layer?
Answer
DNS(Domain Name Service)
Question:
Which two protocols belong to the transport layer?
Answer
TCP, UDP
Question:
When an application sends a packet of information across the network, this packt travels down the IP stack and
undergoes what process?
Answer
Encapsulation
Question:
According to the e2e principle, where should most of the Internet's functionality/Intelligence be implemented
Answer
At the edges of a network
Question:
The difference between hubs, bridges, and routers?
Answer
Hubs: physical layer; bridge: data-link layer; routers:network layer
Question:
What are advantages and disadvantages of a layered architecture?
Answer
Each protocol layer offers different services. Some advantages are scalability, flexibility, and ease of adding / removing
components making it easier for cost-effective implementations. Disadvantages include: some layers functionality
depends on the information from the other layer and violates the goal of layer separation; one layer may duplicate
lower layer functionalities; overhead both in computation and in message headers caused by abstraction barriers
between layers.
Question:
What are the differences and similarities of the OSI model and five-layered Internet model?
Answer
The OSI model and the 5-layered Internet Model have many of the same layers, with the difference being three of the
layers are combined in the 5-layered model. Specifically the five-layer model combines the application, presentation,
and session layers from the OSI model into a single application layer.
Question:
What are sockets?
Answer
A network socket is a software structure within a network node of a computer network that serves as an endpoint for
sending and receiving data across the network. The structure and properties of a socket are defined by an application
programming interface (API) for the networking architecture. Sockets are created only during the lifetime of a process
of an application running in the node.https://en.wikipedia.org/wiki/Network_socket."A process sends messages into,
and receives messages from, the network through a software interface called a socket. Let's consider an analogy to help
us understand processes and sockets. A process is analogous to a house and its socket is analogous to its door....a
socket is the interface between the application layer and the transport layer within a host." - Kurose and Ross, 2.1
Question:
Describe each layer of the OSI model.
Answer
Application layer: Service, Interface, Protocol. Ex: Turn on your smartphone and look at the list of apps. (HTTP,
SMTP, FTP, DNS)
Presentation layer: Plays intermediate role of formatting the information received from the layer below and delivering
it to the application layer. Ex: converting big endian to little endian.
Session layer: Responsible for the mechanism that manages the different transport streams that belong to the same
session between end-user and application process. Ex: teleconference app, it is responsible for tying together audio
and video streaming.
Transport layer: Responsible for the end-to-end communication between end hosts. 2 transport protocols, TCP and
UDP. TCP includes a connection-oriented service to the applications that are running on the layer above, guaranteed
delivery of the application-layer messages, flow control, and congestion control mechanism. UDP provides a
connectionless, best-effort service to the applications that are running in the layer above without reliability, flow, or
congestion control. In this layer the packet is called a segment.
Network layer: This layer is responsible for moving the packet of information, called a datagram, from one host to
another. The network layer is responsible for delivering the datagram to the Transport layer on the destination host. In
this layer there are the IP Protocol and the routing tables.
Data Link layer: Packets are referred to as frames. Examples include: ethernet, ppp, wifi. Responsible for moving the
frames from one node (host or router) to the next node. Services offered by the data link layer protocol include reliable
delivery (transmission of the data from one transmitting node, across one link, to the receiving node.
Physical layer: This layer is the actual hardware responsible to transfer bits within a frame between two nodes
connected through a physical link. Ex: Ethernet (twisted-pair copper, coax, fiber-optics).
Question:
Provide examples of popular protocols at each layer of the five-layered Internet model.
Answer
Application: NFS, DNS, SNMP, ftp, rcp, telnet, HTTP
Transport: TCP, UDP
Internet: IP, ARP, ICMP
Data Link: PPP, IEEE 802.2, Ethernet
Physical Network: Token Ring, RS-232
Question:
What is encapsulation, and how is it used in a layered model?
Answer
Encapsulation is when data (called a header) is appended to the packet through each layer to signify its on the correct
path to the destination host.
Question:
What is the end-to-end (e2e) principle?
Answer
A design choice that shaped the current internet architecture. It states the network core should be simple and minimal,
while the end systems should carry the intelligence. Network functions should be simple and essential commonly used
functions so any host can utilize the service and higher form functions should be built into the application itself. Lower
level layers should be independent and free to perform only their designed function and the higher-level layers deal
with the more intricate functions that deal with the specific application.
Question:
What are the examples of a violation of e2e principle?
Answer
Violations include firewalls and traffic filters. Firewalls violate because they are intermediate devices that are operated
between two end hosts and they can drop the end host communications. Network Address Translation (NAT) boxes
are also a violation because it uses the single public IP address and distributes a new IP scheme to the hosts connected
to it to route data through re-writing the header info to route to the correct destination host. NAT boxes are a violation
because they are not globally addressable or routable.
Question:
What is the EvoArch model?
An hourglass shaped model of the Internet where the outer bands are more frequently modified or replaced and the
further in you go the harder it is for that layer to be altered or modified.
Question:
Explain a round in the EvoArch model.
EvoArch is a discrete-time model that is executed over rounds. At each round, we perform the following steps: A) We
introduce new nodes, and we place them randomly at layers. B) We examine all layers, from the top to the bottom, and
we perform the following tasks: 1) We connect the new nodes that we may have just introduced to that layer, by
choosing substrates based on the generality probabilities of the layer below s(l−1), and by choosing products for them
based on the generality probability of the current layer s(l). 2) We update the value of each node at each layer l, given
that we may have new nodes added to the same layer l. 3) We examine all nodes, in order of decreasing value in that
layer, and remove the nodes that should die. C) Finally, we stop the execution of the model when the network reaches
a given number of nodes.
Question:
What are the ramifications of the hourglass shape of the internet?
A. Many technologies that were not originally designed for the internet have been modified so that they have versions
that can communicate over the internet (such as Radio over IP).
B. It has been a difficult and slow process to transition to IPv6, despite the shortage of public IPv4 addresses.
Question:
Repeaters, hubs, bridges, routers operate on which layers?
Repeaters and Hubs work over L1 (Physical Layer)
Bridges and Layer 2-Switches work over L2 (Data link layer)
Routers and Layer 3-Switches work over L3 (Network layer)
Question:
What is a bridge, and how does it "learn"?
A bridge is a device with multiple inputs/outputs. A bridge transfers frames from an input to one (or multiple)
outputs. Though it doesn't need to forward all the frames it receives.
A learning bridge learns, populates and maintains a forwarding table. The bridge consults that table so that it only
forwards frames on specific ports, rather than over all ports. So how does the bridge learn? When the bridge receives
any frame this is a "learning opportunity" to know which hosts are reachable through which ports. This is because the
bridge can view the port over which a frame arrives and the source host.
Question:
What is a distributed algorithm?
A distributed algorithm is an algorithm designed to run on computer hardware constructed from interconnected
processors. Distributed algorithms are used in many varied application areas of distributed computing, such as
telecommunications, scientific computing, distributed information processing, and real-time proces
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