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Unit 5 - Practice Quiz

CSE306

1 Which of the following best defines the primary function of the Network Layer in the OSI model?

A. Process-to-process delivery
B. Node-to-node delivery with error control
C. Routing and logical addressing
D. Framing and physical addressing

2 In the context of routing algorithms, what does the Optimality Principle state?

A. If router is on the optimal path from router to router , then the optimal path from to also falls along the same route.
B. The shortest path is always the one with the fewest number of hops.
C. The optimal path is determined solely by the bandwidth of the links.
D. All routers must use the same operating system to achieve optimality.

3 Which algorithm is commonly used to calculate the shortest path tree in Link State routing protocols like OSPF?

A. Bellman-Ford Algorithm
B. Dijkstra's Algorithm
C. Floyd-Warshall Algorithm
D. Spanning Tree Protocol

4 In Distance Vector Routing, what information does a router send to its neighbors?

A. The complete topology map of the network
B. The status of its own links only
C. Its entire routing table (vectors of distances)
D. Hello packets to discover neighbors

5 The Count-to-Infinity problem is a specific characteristic/drawback of which routing approach?

A. Link State Routing
B. Distance Vector Routing
C. Source Routing
D. Path Vector Routing

6 Which mechanism prevents the Count-to-Infinity problem by prohibiting a router from advertising a route back onto the interface from which it learned it?

A. Route Poisoning
B. Split Horizon
C. Triggered Updates
D. Hold-down Timers

7 In the Leaky Bucket algorithm, what happens if a packet arrives when the bucket is full?

A. The packet is queued indefinitely.
B. The packet is discarded (dropped).
C. The packet is sent immediately at a higher rate.
D. The bucket expands to accommodate the packet.

8 What is the primary difference between Leaky Bucket and Token Bucket algorithms?

A. Leaky Bucket allows bursty traffic; Token Bucket enforces a constant rate.
B. Leaky Bucket enforces a constant output rate; Token Bucket allows for bursty traffic.
C. Leaky Bucket is used for routing; Token Bucket is used for error control.
D. There is no functional difference.

9 Which routing protocol is an Exterior Gateway Protocol (EGP) used for routing between different Autonomous Systems (AS)?

A. OSPF
B. RIP
C. BGP
D. EIGRP

10 In RIP (Routing Information Protocol), what is the value of the metric that signifies a destination is unreachable (infinity)?

A. 15
B. 16
C. 100
D. 255

11 Which packet is sent by a router to the source to signal congestion, effectively telling the source to slow down?

A. Hello Packet
B. LSA Packet
C. Choke Packet
D. Keepalive Packet

12 In Link State Routing, how is the topological information disseminated?

A. By exchanging routing tables with neighbors only.
B. By flooding Link State Packets (LSPs) to all routers in the area.
C. By sending path vectors to the central controller.
D. By querying the DNS server.

13 Congestion control that relies on the receiver sending feedback to the sender is classified as:

A. Open-loop congestion control
B. Closed-loop congestion control
C. Static congestion control
D. Forward error correction

14 What is the formula for the updating rule in the Bellman-Ford equation used in Distance Vector routing? (Where is the cost from to , and is the cost to neighbor )

A.
B.
C.
D.

15 Which of the following describes Flooding?

A. A packet is sent only to the destination address.
B. A packet received on one line is sent out on all other lines.
C. Packets are held in a buffer until the line is clear.
D. Packets are sent based on a probability distribution.

16 OSPF (Open Shortest Path First) divides an Autonomous System into:

A. Zones
B. Areas
C. Clusters
D. Segments

17 What is Backpressure in the context of congestion control?

A. Discarding packets at the tail of the queue.
B. Node-by-node congestion propagation in the reverse direction of data flow.
C. Increasing the window size to push more data.
D. Prioritizing voice traffic over data traffic.

18 Which of the following is a Unicast routing protocol?

A. DVMRP
B. PIM
C. RIP
D. MOSPF

19 The Token Bucket algorithm requires which two parameters?

A. Bucket size and Leak rate
B. Burst size and Maximum delay
C. Token generation rate and Bucket capacity
D. Hop count and Bandwidth

20 Which mechanism allows a router to randomly drop packets before its queue becomes full to prevent global synchronization of TCP sessions?

A. Tail Drop
B. RED (Random Early Detection)
C. Leaky Bucket
D. Priority Queuing

21 BGP uses which type of routing algorithm?

A. Distance Vector
B. Link State
C. Path Vector
D. Shortest Path First

22 In Hierarchical Routing, routers are grouped into:

A. Regions or Clusters
B. Vectors
C. Subnets only
D. Datagrams

23 Which of the following is a symptom of severe congestion?

A. Low latency
B. High throughput
C. Packet loss and increased delay
D. Increased bandwidth

24 In the TCP Congestion Control mechanism (often discussed in network layer contexts regarding flow interaction), what happens during the 'Slow Start' phase?

A. The congestion window increases linearly.
B. The congestion window increases exponentially.
C. The congestion window remains constant.
D. The sender stops sending packets.

25 What is the 'Poison Reverse' technique?

A. A security attack on routing tables.
B. A variation of Split Horizon where the route is advertised with a cost of infinity.
C. Reversing the path of the packet to the source.
D. Flooding bad packets to clear the buffer.

26 Which routing algorithm requires a global knowledge of the network topology?

A. Distance Vector
B. Link State
C. Flooding
D. Random Walk

27 What is the standard administrative distance (trustworthiness) order for these protocols (Lowest to Highest implies Most to Least trusted)?

A. RIP < OSPF < Connected Interface
B. Connected Interface < OSPF < RIP
C. OSPF < Connected Interface < RIP
D. RIP < Connected Interface < OSPF

28 Which concept refers to the maximum amount of data that the network can transmit per unit of time?

A. Latency
B. Jitter
C. Throughput
D. Packet Delay

29 In the context of Quality of Service (QoS), Jitter refers to:

A. The total time taken for a packet to reach the destination.
B. The variation in packet arrival times.
C. The number of packets lost.
D. The size of the packet header.

30 In Congestion Control, what is Load Shedding?

A. Adding more routers to the network.
B. Dropping packets when routers cannot process them fast enough.
C. Distributing traffic equally among all links.
D. Compressing data to reduce size.

31 Which BGP attribute is used to detect loops in routing paths?

A. Next Hop
B. AS_PATH
C. Local Preference
D. MED

32 What happens in the Congestion Avoidance phase of TCP (AIMD)?

A. Window size doubles every RTT.
B. Window size increases by 1 segment (MSS) every RTT.
C. Window size is cut to zero.
D. Window size grows exponentially.

33 ECN (Explicit Congestion Notification) allows routers to:

A. Drop packets immediately.
B. Mark packets to signal impending congestion to endpoints without dropping them.
C. Reroute packets to a faster path.
D. Increase the bandwidth of the link.

34 The Knee in the throughput vs. load graph represents:

A. The point where throughput drops to zero.
B. The point where throughput stops increasing linearly and delay starts increasing rapidly.
C. The maximum capacity of the link.
D. The point of zero latency.

35 Which of the following is true for Static Routing?

A. Routes are updated automatically when topology changes.
B. It is suitable for very large, changing networks.
C. Routes are manually configured by the administrator.
D. It uses complex algorithms like Dijkstra.

36 In OSPF, the Backbone Area is numbered as:

A. Area 1
B. Area 100
C. Area 0
D. Area 255

37 Which variable tracks the available capacity in a Token Bucket algorithm?

A. Counter
B. Window Size
C. TTL
D. Sequence Number

38 What is the main disadvantage of Flooding?

A. It is not robust.
B. It always finds the longest path.
C. It generates a vast number of duplicate packets, wasting bandwidth.
D. It requires complex routing tables.

39 RIP updates are sent periodically every:

A. 10 seconds
B. 30 seconds
C. 60 seconds
D. 90 seconds

40 Traffic Shaping is about:

A. Dropping packets that exceed limits.
B. Controlling the rate of traffic sent to the network to comply with a profile.
C. Compressing headers.
D. Encrypting the payload.

41 In the context of routing, what is Convergence?

A. The process of combining two networks.
B. The state where all routers share a consistent view of the network.
C. The compression of routing tables.
D. The merging of two distinct packets.

42 What type of graph search does the Distance Vector algorithm effectively perform?

A. Breadth-First Search
B. Distributed Bellman-Ford
C. Depth-First Search
D. Minimum Spanning Tree

43 Which field in the IP header is used to prevent infinite looping of packets?

A. Checksum
B. Version
C. Time to Live (TTL)
D. Fragment Offset

44 In a Datagram network (Connectionless), routing decisions are made:

A. Only once at the connection setup.
B. For every individual packet.
C. Only at the source node.
D. Only at the destination node.

45 If a router receives a packet with a destination address that is not in its routing table, and no default route exists, what does it usually do?

A. Broadcasts the packet to all ports.
B. Sends the packet back to the sender.
C. Discards the packet and sends an ICMP Destination Unreachable message.
D. Holds the packet until a route appears.

46 The Cliff in the Load vs. Throughput/Delay graph signifies:

A. The point where congestion begins.
B. The point where throughput collapses heavily due to extreme congestion.
C. The ideal operating point.
D. The start of the slow start phase.

47 RSVP (Resource Reservation Protocol) is used primarily for:

A. Routing table updates.
B. Reserving resources (bandwidth/buffers) for QoS flows.
C. Assigning IP addresses.
D. Detecting link failures.

48 In Dijkstra's algorithm, which data structure is typically used to select the node with the smallest tentative distance?

A. Stack
B. Queue
C. Priority Queue
D. Linked List

49 What is the primary metric used by OSPF to calculate cost?

A. Hop Count
B. Bandwidth
C. Delay
D. Load

50 Which of the following describes Multipath Routing?

A. Routing all traffic through a single best path.
B. Sending the same packet over multiple paths for redundancy.
C. Distributing traffic load over multiple available paths to the same destination.
D. Routing based on multiple metrics like delay and cost combined.