Routing

Question 1
 
A
I and IV only
B
I, II and III only
C
I, II and IV only
D
II, III and IV only
       Computer-Networks       Routing       GATE 2017(set-02)
Question 1 Explanation: 
I: RIP uses distance vector routing. “TRUE”
RIP is one of the oldest DVR protocol which employ the hop count as a routing metric.
II: RIP packets are sent using UDP. “TRUE”
RIP uses the UDP as its transport protocol, and is assigned the reserved port no 520.
III: OSPF packets are sent using TCP. “FASLE”
OSPF encapsulates its data directly into IP Packets and does not use either TCP or UDP.
IV: OSPF operation is based on link state routing. “TRUE”
OSPF is a routing protocol which uses link state routing (LSR) and works within a single autonomous system.
Hence correct is answer “C”.
Question 2
A
S1, S2, and S3 are all true.
B
S1, S2, and S3 are all false.
C
S1 and S2 are true, but S3 is false.
D
S1 and S3 are true, but S2 is false.
       Computer-Networks       Routing       GATE 2014(Set-01)
Question 2 Explanation: 
S1: The computational overhead in link state protocols is higher than in distance vector protocols. Because LSR is based upon global knowledge whereas DVR is based upon Local info.(True)
S2: A distance vector protocol with split horizon avoid persistent routing loops is true, but not a link state protocol is false because link state protocols do not have count to infinity problem.
S3: As Distance vector protocol has count to infinity problem and converges slower. (True)
Question 3
Which one of the following is TRUE about the interior gateway routing protocols – Routing Information Protocol (RIP) and Open Shortest Path First (OSPF)?
A
RIP uses distance vector routing and OSPF uses link state routing
B
OSPF uses distance vector routing and RIP uses link state routing
C
Both RIP and OSPF use link state routing
D
Both RIP and OSPF use distance vector routing
       Computer-Networks       Routing       Gate 2014 Set -02
Question 3 Explanation: 
RIP Uses Distance Vector Routing and OSPF uses Link State Routing.
Question 4
   
A
(3, 2, 0, 2, 5)
B
(3, 2, 0, 2, 6)
C
(7, 2, 0, 2, 5)
D
(7, 2, 0, 2, 6)
       Computer-Networks       Routing       Gate 2011
Question 4 Explanation: 
Question 5
   
A
3
B
9
C
10
D
       Computer-Networks       Routing       Gate 2011
Question 5 Explanation: 
N3 has neighbors N2 and N4
N2 has made entry ∞
N4 has the distance of 8 to N1
N3 has the distance of 2 to N4
So 2 + 8 = 10
Question 6
A
4
B
3
C
2
D
1
       Computer-Networks       Routing       2010
Question 6 Explanation: 
Link R1- R2 will not be used because its cost is 6 and link R1-R3-R2 costs 5, which is lesser than R1-R2 link.
Similarly, link R4-R6 will not be used, instead this link we can use R4-R5-R6 link which costs only 5 unit.
Question 7
 
A
0
B
1
C
2
D
4
       Computer-Networks       Routing       2010
Question 7 Explanation: 
Now Graph will look like

And only link that will be removed is R5-R6 link.
Question 8
 
A
S1, S2 and S4 only
B
S1, S3 and S4 only
C
S2 and S3 only
D
S1 and S4 only
       Computer-Networks       Routing       Gate 2008-IT
Question 8 Explanation: 
→ Count to infinity problem only exist into the DVR.
→ In LSR shortest path is calculated at each every router. (B) is wrong.
→ In DVR also shortest path is calculated at each and every router. (C) is wrong.
→ Since DVR is based upon local knowledge whereas LSR is based upon global knowledge.
Question 9
Packets of the same session may be routed through different paths in:  
A
TCP, but not UDP
B
TCP and UDP
C
UDP, but not TCP
D
Neither TCP nor UDP
       Computer-Networks       Routing       Gate-2005
Question 9 Explanation: 
Both TCP and UDP uses IP, which is a datagram service.
There are 9 questions to complete.