ISYE 6402 COMPREHENSIVE STUDY GUIDE
2026 FULL QUESTIONS AND SOLUTIONS
GRADED A+
◍ Smoothing.
Answer: Spikes in data are smoothed down
◍ Provide examples of popular protocols at each layer of the five-layered
Internet model..
Answer: Application: NFS, DNS, SNMP, ftp, rcp, telnet, HTTPTransport:
TCP, UDPInternet: IP, ARP, ICMPData Link: PPP, IEEE 802.2,
EthernetPhysical Network: Token Ring, RS-232
◍ 3 potions of a data set.
Answer: 1. training- data set to fit the model2. validating-chooses best
model3. testing- estimates performance of chosen model
◍ What is hot potato routing?.
Answer: Hot potato routing is a technique/practice of choosing a path within
the network, by choosing the closest egress point(network exit) based on
intra domain path cost (Interior Gateway Protocol/IGP cost).Hot potato
routing simplifies computations for the routers as they are already aware of
the IGP path costs. It makes sure that the path remains consistent, since the
next router in the path will also choose to send the packet to the same egress
point.Hot potato routing also effectively reduces the network's resource
consumption by getting the traffic out as soon as possible.
◍ Quantitative Data.
Answer: Most numerical data, numbers have a meaning
◍ ● When does the count-to-infinity problem occur in the distance vector
algorithm?.
, Answer: When two or more nodes keep updating their values and informs
the neighbors of the change and they in turn update their values causing the
original root to update its value again. This continues for a long time in a
constant loop.This happens primarily when a neighbor's advertised path
includes the present node's path as a loop.
◍ Time series data.
Answer: same data recorded over time, often at different intervals
◍ Classification.
Answer: The process of grouping things based on their similaritiesEx.
Classifying consumers by who is likely to pay back a loan and who is not
◍ Basic Learning Algorithms.
Answer: Among the first algorithms learned--ex. Linear Regression.Logistic
Regression.Decision Tree.SVM.Naive Bayes.kNN.K-Means.
◍ 2 types of patterns in data.
Answer: real effect-real relationship between attribute and response, same in
all data setsrandom effect- random, but looks like a real effect, different
across data sets
◍ 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.
◍ Explain the TCP connection teardown..
Answer: Teardown:Step 1: When client wants to end the connection, it
sends a segment with FIN bit set to 1 to the server.Step 2: Server
acknowledges that it has received the connection closing request
(FIN-ACK) and is now working on closing the connection.Step 3: The
, Server then sends a segment with FIN bit set to 1, indicating that connection
is closed.Step 4: The Client sends an ACK for it to the server. It also waits
for sometime to resend this acknowledgment in case the first ACK segment
is lost.
◍ ● What are the goals of congestion control?.
Answer: Efficiency. We should get high throughput or utilization of the
network should be high.Match the load to available capacity.Fairness. Each
user should have its fair share of the network bandwidth. The notion of
fairness is dependent on the network policy. For this context, we will
assume that every flow under the same bottleneck link should get equal
bandwidth.Low delay. In theory, it is possible to design protocols that have
consistently high throughput assuming infinite buffer. Essentially, we could
just keep sending the packets to the network and they will get stored in the
buffer and will eventually get delivered. However, it will lead to long
queues in the network leading to delays. Thus, applications that are sensitive
to network delays such as video conferencing will suffer. Thus, we want the
network delays to be small.Fast convergence. The idea here is that a flow
should be able to converge to its fair allocation fast. This is important as a
typical network's workload is composed of a lot of short flows and few long
flows. If the convergence to fair share is not fast enough, the network will
still be unfair for these short flows.
◍ ● What are / were the original design goals of BGP? What was considered
later?.
Answer: The original design goals of BGP were:1. Scalabilitymanage the
complications of this growth, while achieving convergence in reasonable
timescales and providing loop-free paths.2. Express routing policiesBGP has
defined route attributes that allow ASes to implement policies (which routes
to import and export), through route filtering and route ranking3. Allowing
cooperation among ASesindividual AS can still make local decisions (which
routes to import and export) while keeping these decisions confidential from
other ASes.Security was considered later as the complexity and size of the
Internet has been increasing. Solutions have not been widely deployed or
, adopted due to difficulty to transition to new protocols and lack of
incentives.
◍ Heuristic.
Answer: An algorithm that's not guaranteed to find the best solution, but in
many cases it usually gets very close to the absolute best solution and it gets
us there quickly
◍ 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.
◍ Hyperplane.
Answer: 1. A flat affine subspace of dimension p-1! 2. 2 dimensions-flat one
dimensional subspace- a line3. 3 dimensions- flat two dimensional
subspace- a plane
◍ ● What is an AS?.
Answer: AS stands for autonomous systems. ISPs, IXPs and CDNs can all
operate as an AS. An AS is a group of routers including the links among
them that operate under the same administrative authority.
◍ ● Explain TCP throughput calculation..
Answer: The calculation is:P = Probability of packet lossMSS = Maximum
Segment SizeRTT = Round-Trip TimesBW = data per cycle / time per
cycleBW = MSS/RTT * C / sqrt(P)
◍ Explain the Spanning Tree Algorithm..
Answer: The algorithm runs in "rounds" and at every round each node sends
to each neighbor node a configuration message with three fields: a) the
sending node's ID, b) the ID of the roots as perceived by the sending node,
and c) the number of hops between that (perceived) root and the sending
node.At every round, each node keeps track of the best configuration
message that it has received so far, and it compares that against the
configuration messages it receives from neighboring nodes at that round.At
2026 FULL QUESTIONS AND SOLUTIONS
GRADED A+
◍ Smoothing.
Answer: Spikes in data are smoothed down
◍ Provide examples of popular protocols at each layer of the five-layered
Internet model..
Answer: Application: NFS, DNS, SNMP, ftp, rcp, telnet, HTTPTransport:
TCP, UDPInternet: IP, ARP, ICMPData Link: PPP, IEEE 802.2,
EthernetPhysical Network: Token Ring, RS-232
◍ 3 potions of a data set.
Answer: 1. training- data set to fit the model2. validating-chooses best
model3. testing- estimates performance of chosen model
◍ What is hot potato routing?.
Answer: Hot potato routing is a technique/practice of choosing a path within
the network, by choosing the closest egress point(network exit) based on
intra domain path cost (Interior Gateway Protocol/IGP cost).Hot potato
routing simplifies computations for the routers as they are already aware of
the IGP path costs. It makes sure that the path remains consistent, since the
next router in the path will also choose to send the packet to the same egress
point.Hot potato routing also effectively reduces the network's resource
consumption by getting the traffic out as soon as possible.
◍ Quantitative Data.
Answer: Most numerical data, numbers have a meaning
◍ ● When does the count-to-infinity problem occur in the distance vector
algorithm?.
, Answer: When two or more nodes keep updating their values and informs
the neighbors of the change and they in turn update their values causing the
original root to update its value again. This continues for a long time in a
constant loop.This happens primarily when a neighbor's advertised path
includes the present node's path as a loop.
◍ Time series data.
Answer: same data recorded over time, often at different intervals
◍ Classification.
Answer: The process of grouping things based on their similaritiesEx.
Classifying consumers by who is likely to pay back a loan and who is not
◍ Basic Learning Algorithms.
Answer: Among the first algorithms learned--ex. Linear Regression.Logistic
Regression.Decision Tree.SVM.Naive Bayes.kNN.K-Means.
◍ 2 types of patterns in data.
Answer: real effect-real relationship between attribute and response, same in
all data setsrandom effect- random, but looks like a real effect, different
across data sets
◍ 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.
◍ Explain the TCP connection teardown..
Answer: Teardown:Step 1: When client wants to end the connection, it
sends a segment with FIN bit set to 1 to the server.Step 2: Server
acknowledges that it has received the connection closing request
(FIN-ACK) and is now working on closing the connection.Step 3: The
, Server then sends a segment with FIN bit set to 1, indicating that connection
is closed.Step 4: The Client sends an ACK for it to the server. It also waits
for sometime to resend this acknowledgment in case the first ACK segment
is lost.
◍ ● What are the goals of congestion control?.
Answer: Efficiency. We should get high throughput or utilization of the
network should be high.Match the load to available capacity.Fairness. Each
user should have its fair share of the network bandwidth. The notion of
fairness is dependent on the network policy. For this context, we will
assume that every flow under the same bottleneck link should get equal
bandwidth.Low delay. In theory, it is possible to design protocols that have
consistently high throughput assuming infinite buffer. Essentially, we could
just keep sending the packets to the network and they will get stored in the
buffer and will eventually get delivered. However, it will lead to long
queues in the network leading to delays. Thus, applications that are sensitive
to network delays such as video conferencing will suffer. Thus, we want the
network delays to be small.Fast convergence. The idea here is that a flow
should be able to converge to its fair allocation fast. This is important as a
typical network's workload is composed of a lot of short flows and few long
flows. If the convergence to fair share is not fast enough, the network will
still be unfair for these short flows.
◍ ● What are / were the original design goals of BGP? What was considered
later?.
Answer: The original design goals of BGP were:1. Scalabilitymanage the
complications of this growth, while achieving convergence in reasonable
timescales and providing loop-free paths.2. Express routing policiesBGP has
defined route attributes that allow ASes to implement policies (which routes
to import and export), through route filtering and route ranking3. Allowing
cooperation among ASesindividual AS can still make local decisions (which
routes to import and export) while keeping these decisions confidential from
other ASes.Security was considered later as the complexity and size of the
Internet has been increasing. Solutions have not been widely deployed or
, adopted due to difficulty to transition to new protocols and lack of
incentives.
◍ Heuristic.
Answer: An algorithm that's not guaranteed to find the best solution, but in
many cases it usually gets very close to the absolute best solution and it gets
us there quickly
◍ 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.
◍ Hyperplane.
Answer: 1. A flat affine subspace of dimension p-1! 2. 2 dimensions-flat one
dimensional subspace- a line3. 3 dimensions- flat two dimensional
subspace- a plane
◍ ● What is an AS?.
Answer: AS stands for autonomous systems. ISPs, IXPs and CDNs can all
operate as an AS. An AS is a group of routers including the links among
them that operate under the same administrative authority.
◍ ● Explain TCP throughput calculation..
Answer: The calculation is:P = Probability of packet lossMSS = Maximum
Segment SizeRTT = Round-Trip TimesBW = data per cycle / time per
cycleBW = MSS/RTT * C / sqrt(P)
◍ Explain the Spanning Tree Algorithm..
Answer: The algorithm runs in "rounds" and at every round each node sends
to each neighbor node a configuration message with three fields: a) the
sending node's ID, b) the ID of the roots as perceived by the sending node,
and c) the number of hops between that (perceived) root and the sending
node.At every round, each node keeps track of the best configuration
message that it has received so far, and it compares that against the
configuration messages it receives from neighboring nodes at that round.At
