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}