Advanced Computer Networks Quiz 3

1.Between three mobility choices: i) Etherent        ii) IP Routing        iii) Mobile IP

Which mobility choice provides less efficient communication when node moves?

Select one:
a. Mobile IP{correct}
b. IP Routing and Mobile IP Both
c. IP Routing
d. Mobile IP and Ethernet Both

2.Which of the following is not an appropriate objective for Data Center Networks?
Select one:
a. Assigning servers to service should be dependent of network topology{correct}
b. Maximum rate of server to server traffic flow should be limited only by capacity on network cards
c. Traffic of one service should not be affected by traffic of other services
d. Capapble to assign any service to any server

3.An extra DNS lookup is required in-
Select one:
a. Cluster based Routing
b. Anycast Routing
c. HTTP redirection{correct}
d. DNS redirection

4.Which of the following protocols can be used as south bound protocol to extract topology information for a SDN controller?

Select one or more:
{correct} choose all
a. LISP{correct}
b. BGP{correct}
c. TCP
d. SNMP{correct}

5.Which of the following is TRUE for the snoopy protocol approach used for improving TCP performance over wireless links?
Select one:
a. It voilates end to end semantics of Internet design
b. It increases the possibility of the adverse interactions between protocol layers
c. It compltely shields the TCP sender from the wireless losses{correct}
d. TCP protocol processing at base more complex

6.Consider the argument: "The link layer protocols can shield the TCP sender from wireless losses by local retransmissions."
Select one:
a. FALSE
b. TRUE{correct}
c. Can't Say

7.Which of the following service function does not belong to the basic service function category for the Open Daylight controller?

Select one:
a. VTN Manager{correct}
b. Host-Tracker
c. Topology Manager
d. Forwarding Manager

8.The use of PEPs has not been encourged to integrate challenged networks into the existing TCP/IP architecture because of
Select one or more:
a. they can not handle the mobility
b. they store state of connection which is nessasary for the connectin operation{correct}
c. Use of these violates the fate sharing principle{correct}
d. they can pose challenge for end to end security mechanism implemented below transport layer{correct}

9.Which of the following is better in terms of number of messages (consider average case) required per lookup?
Select one:
a. Gnutella
b. Chord
c. Kazaa
d. Napster{correct}


10.Consider A, B, C, and D are wireless nodes shown in Figure.

Assume there is an ongoing transmission from node B to A. Can node C initiate a transmission to node D. Assume nodes are following MACAW (Multiple Access with Collision Avoidance for Wireless networks) protocol for media access? The signal interference range is shown with ovals.

Select one:
a. No
b. Yes, with assuming that the nodes are synchronized with respect to packet size and data rate.{correct}
c. Yes

Advanced Computer Networks Quiz 2

1.Consider the Chord system where key and node identifiers are represented by 6 bits length (m=6). A lookup request for the key 28 has arrived at node N1. How many messages will require to get the desired key. (Assume that the key is available and nodes are maintaining Finger table of m/2 entries) 

Select one:
a. 2
b. 3
c. Undetermined
d. 1
e. 4{correct}

2.Three MPTCP flows (each of them having 2 sub-flows) are sharing links as shown in the figure. What will be the bandwidth share for each of the MPTCP flows? Assume MPTCP flows are using Equal Weight Congestion Protocol. The link capacities are mentioned over the links.

Select one:
a. Flow 1 = 11 Mbps, Flow 2 = 15 Mbps, Flow 3 = 8 Mbps
b. Flow 1 = 8 Mbps, Flow 2 = 20 Mbps, Flow 3 = 6 Mbps
c. Flow 1 = 11 Mbps, Flow 2 = 12 Mbps, Flow 3 = 11 Mbps{correct}
d. Flow 1 = 10 Mbps, Flow 2 = 14 Mbps, Flow 3 = 10 Mbps

3.Which of the following is/are not TRUE for CORAL CDN?
Select one or more:
a. It uses DHT for value/key distribution{correct}
b. CORAL Client's needs to be modified accordingly before requesting for any object{correct}
c. It is a Peer to Peer web content distribution network.
d. It does clustering of nodes to handle requests in efficient manner

4.Which of the following is correct about BGP and Resilient Overlay Networks(RONs)?
Select one:
a. In RON application specific routing can be achieved but in BGP it is not possible{correct}
b. RON is more scalable than BGP
c. Link failure detection is fast in BGP as compared to RONs
d. BGP provides optimal routing as compared to RONs

5.Assume you have a Chord system of 5 nodes with identifiers 0, 1, 2, 4, and 7. Assume the identifier space is 0-9. Which of the following is/are correct "node-key" pair combination?
Select one or more:
a. 7,6{correct}
b. 4,5
c. 0,8{correct}
d. 2,3

6.Which of the following is not TRUE for the Prefix aggregation used in BGP protocol?
Select one:
a. Enabling Prefix aggregation in BGP router could be a cause of BGP mis-configuration type
b. Aggregated Prefix hijacks do more damage than non aggregated prefix hijacks
c. In prefix aggregation process AS path can loose it's origin information
d. Route distribution across the network is better for aggregated prefix as compared to non-aggregated prefixes{correct}

7.Which of the following is TRUE for the Resilient Overlay (RON) Network for routing-
Select one:
a. RON nodes exchange information about the quality of the paths among themselves via a separate routing protocol
b. The nodes comprising a RON should reside in same Autonomous System (AS)
c. It is network layer overlay
d. RON recovers from failure using physical path redundancy available at underlying topology{correct}

8.Which of the BGP path attribute(s) can be used by an ISP to route the traffic as per its own traffic engineering requirements?
Select one or more:
a. Local Preference{correct}
b. Origin
c. MED{correct}
d. AS Path

9.Which of the following is/are TRUE for the MPLS based routing?

Select one or more:
a. It works at Layer-2 in IP Network
b. It works independent of underlying network{correct}
c. It does circuit switching
d. It does packet switching{correct}

10.Which of these is/are can be probable cause of oscillations in routes in BGP?
Select one or more:
a. Misconfigurations in routing tables{correct}
b. Policy disputes{correct}
c. Prefix aggregation
d. Non monotonic ranking used for paths{correct}

11.Which of the following is TRUE for MPTCP protocol but FALSE for TCP protocol?

Select one:
a. Does Congestion Control
b. Does Flow Control
c. Does Reliable data Transfer
d. Does Traffic Load Balancing{correct}

12.Consider the Chord system where key and node identifiers are represented by 6 bits length. A lookup request for the key 40 has arrived at node N1. How many messages will be required to get access of the desired key. (Assume that the key is available and nodes are not maintaining any Finger table) 

Select one:
a. 6{correct}
b. 5
c. 1
d. 3
e. 4

13.Which of these method is used by CORAL CDN to choose an appropriate server to satisfy the user request?
Select one:
a. DNS redirection{correct}
b. HTTP redirection
c. Routing redirection
d. Anycast

14.Which of the following is not an example of structured loookup service?
Select one:
a. Tapestry
b. Pastry
c. Chord
d. Gnutella{correct}

15.Which of these is NOT an example of related origin misconfiguration for a route "a.0.0.0/8 PQR" in BGP?
Select one:
a. a.0.0.0/8 PQ
b. a.b.0.0/16 PQ{correct}
c. a.b.c.0/24 PQRS
d. a.b.0.0/16 PQR

16.A BGP router is not allowed to advertised the prefix learned from one of its I-BGP neighbor to its another I-BGP neighbor because of:
Select one:
a. Scalability Problem
b. Looping Problem{correct}
c. Control traffic overhead
d. Policy reason

17.In general, which order is followed by ASes as per local preferences to import a route?
Select one:
a. Provider > Customer > Peer
b. Customer > Peer > Provider{correct}
c. Peer > Customer > Provider
d. Provider > Peer > Customer


18.Consider the Chord system where key and node identifiers are represented by 6 bits length (i.e. m=6). A lookup request for the key 28 has arrived at node N1. How many messages will require to get the desired key. (Assume that the key is available and nodes are maintaining Finger table of m entries) 

Select one:
a. 3
b. Undetermined
c. 4
d. 2{correct}
e. 1

19.Which of the following are valid points for a source routing protocol?

Select one or more:
a. The source can exploit knowledge of the performance or reliability of the links to route data.{correct}
b. The source can pick a path that matches the application requirements.{correct}
c. The source can not avoid un-trusted links or ASes in path selection.
d. The source can react quickly to changes in the network conditions as compared to destination based routing.{correct}

20.The Coupled congestion algorithm used for MPTCP gives unfair bandwidth distribution among multiple flows over a bottleneck link due to -

Select one or more:
a. Change in total traffic load on paths used by MPTCP sub-flows {correct}
b. more number of flows on a bottleneck link 
c. mix of MPTCP and TCP flows on a bottle link 
d. Mismatch in RTT values of different paths used by MPTCP sub-flows {correct}

Advanced Computer Networks Quiz 1

1.Which of the following does not voilate end to end principle of Internet design?
Select one:
a. Packet sniffer{correct}
b. NAT Router
c. Proxy Server
d. Firewall

2.Which of these is/are become easy to achieve in the Internet using Datagram approach-

Select one or more:
a. Resource Management
b. Providing multiple services{correct}
c. Surviability{correct}
d. Connecting different types of networks{correct}

3.Which of the following is correctly defines RED gatways?
Select one:
a. Differentiate between persistent and intermittent congestion level{correct}
b. Consider only the intermittent congestion level
c. Consider only the persistent congestion level
d. Can not identify the connections, which uses more bandwidth than others

4.Which of the following is NOT true for linear control based congestion control mechanism?
Select one:
a. Multiplicative increase and additive increase improves utilization
b. Multiplicative increase or multiplicative decrease doesn't change in fairness
c. Additive increase reduces fairness and additive decrease improves fairness{correct}
d. Additive increase improves fairness and additive decrease reduces fairness

5.Which of these has not been mentioned as a design goal for the Ineternet design in the Clark's paper on Design Philosophy of DARPA Internet Design?
Select one:
a. Resource Acountability
b. Cost Effectiveness
c. Surviability
d. Security{correct}

6.Which of the following is/are violates the Internet's End to End principle?
Select one or more: 2 are correct but i selected all that's also correct'
a. File Sharing using FTP
b. NAT Firewall{correct}
c. HTTP Proxy Server{correct}
d. Virtual Private Networking (VPN)

7.The TCP's sender side window size is NOT dependent on-
Select one:
a. Maximum Segment Size (MSS){correct}
b. Network Congestion
c. Receiver side buffer space
d. Round Trip Time (RTT)

8.Consider an application that transmits data at a steady rate (for example, the sender generates an N bit unit of data every k time units, where k is small and fixed). Also, when such an application starts, it will continue running for a relatively long period of time. Which type of network will be more appropriate for this application?
Select one:
a. Circuit Switched{correct}
b. Application performance is independent to the Networks types
c. Can not determined
d. Packet Switched

9.Which of the following is not an appropriate reason for congestion collapse
Select one:
a. Undelivered packets in the network
b. Bursty traffic nature{correct}
c. Mismatch of transmission and retransmission packet size
d. Spurious retransmissions of packets still in flight

10.Which of these congestion control policy is not used at Transport layer in the Internet?
Select one:
a. Packet discard policy{correct}
b. Out of order packet caching
 c. Timeout
 d. Negative Acknowledgement

11.Consider, the four flows with their corresponding demands are 2, 2.6, 4 and 5 units. The total capacity of the link is 10 units. What will be the correct sequence of bandwidth allocation for these flows using Max-min algorithm?
Select one:
 a. 2.0, 2.6, 2.6, 2.8
 b. 2.0, 2.6, 2.7, 2.7{correct}
 c. 2.0, 2.6, 2.4, 3.0
 d. 2.6, 2.0, 2.7, 2.7

12.Which of the following tussle example belongs to the Tussle of Trust as per "Tussle in Cyber Space....? paper? 

Select one:
 a. Customer want to share the contents but proprietary content holders do not like it
 b. ISPs does application filtering/monitoring but customer don't like it{correct}
 c. ISPs insists customers to use certain services offered by them only
 d. Customers tussle with providers to get the service at a low price

13.Consider a link having a capacity of 12Mbps. Four flows, f1, f2, f3 and f4 , all send traffic over this link at rates r1=2Mbps, r2=4Mbps, r3=3Mbps and r4=6Mbps respectively. Under max-min fairness allocation, what outgoing rate does each flow receive through this link?
Select one:
 a. f1=2Mbps, f2=3.5Mbps, f3=3Mbps, f4=3.5Mbps{correct}
 b. f1=2Mbps, f2=4Mbps, f3=3Mbps, f4=3Mbps
 c. f1=2Mbps, f2=3.5Mbps, f3=3.5Mbps, f4=3Mbps
 d. f1=2Mbps, f2=2Mbps, f3=3Mbps, f4=5Mbps

14.Host A sends a TCP segment (Seq=43, ACK=103) with payload (i.e. application data) of 20 bytes. The host B successfully received the segment and wants to send a segment with payload of 28 bytes. What will be the value of Seq and ACK field in the reply from host B? Assume that host A sends the first segment to the host B after connection setup.
Select one:
 a. Seq=44, ACK=63
 b. Can't find with given data
 c. Seq=103, ACK=63{correct}
 d. Seq=81, ACK=103

15.The TCP round trip time (RTT) is currently 300 msec. Three RTT samples has been collected as 260, 320, and 240 msec, respectively, what is the new estimated RTT after second sample according to jacobson's formula? Assume α = 0.8
Select one:
 a. 292.6 ms
 b. 292 ms
 c. 297.6 ms{correct}
 d. 296.2 ms

16.Which of the following is/are TRUE for TCP protocol?

Select one or more:
 a. It is a byte stream protocol{correct}
 b. TCP receiver doesn't receive out of order packets
 c. It supports reliable in order delivery of packets{correct}
 d. TCP receiver doesn't send cumulative ACKs
 e. It does flow control{correct}

17.When multiple packets are dropped from a single window, which of the TCP implementation is good in reducing spurious retransmissions?
Select one:
 a. Reno
 b. Vegas
 c. Westwood
 d. SACK{correct}
 e. Tahoe

18.Which of the queuing method implemented at the router does suffer from the global window synchronization problem?
Select one:
 a. RED
 b. FQ + Random
 c. FIFO + DropTail{correct}

19.The three TCP flows are sharing a bottleneck link. The bandwidth share among them is 2,4, and 4 Mbps respectively. What is the fairness ratio for the link?
Select one:
 a. 0.755
 b. 0.852
 c. 0.850
 d. 0.925{correct}
 e. 0.700

20.As per Name Data Networking (NDN) architecture, an interest packet can be forwarded to multiple interfaces by a router. This can lead to a looping problem. Which of the following is the correct justification to say that packet is not going to loop?

Select one:
 a. The information contained in PIT avoids the looping
 b. The uniqueness of interest packets is identified by a time stamp value
 c. The Nonce field in the packet takes care of it{correct}
 d. NDN inherently supports multi-path routing