Cisco Most Frequently Asked Interview Questions

Cisco most Frequently Asked interview question in various interview

,We heartily Thanks to our couple of Visitors who shared these questions with Q4Interview.

1.    Reverse a string in C using as little additional memory as possible.

2.    Setting, Clearing and Toggling a single bit in a value..?

3.    Difference between macro and inline functions ?

4.    Find nth node from last in single linked list

5.    How will you implement macro sizeof    

6.    How will you organize 1 lakh numbers??

7.    Difference between little endian and big endian,write a code that tells you machine is little or big endian ??

8.    What is NAT   ??

9.    What things will you keep in mind while writing a high level design ??

10. How will you allocate a memory to 2d integer array ??

11. What is alignment ??

12. How will you align an allocated pointer ??

13. Write a code for reversing a linked list, recursive and non-recursive.

14. How to find whether a machine is 32bit or 64 bit? Write code for this..??

15. What is Y shape linked list.. ??

16. How will you implement a linked list library using void pointers? Write the complete code

17. Sorted array is given, find 2 nos whose sum equals X ??

18. Complement the odd bits in a byte                                         

19. How does traceroute works                                                     

20. What are the different means of IPC in linux kernel                 

21. What is difference between process and threads                                 

22. What is difference between const char *, char const * etc...    

23. Write a code to merge two sorted linked lists                          

24. If ttl is set to 15 and we have 10 machines, and each machine takes 2 seconds to process the packet, will the packet reach the end point?                        

25. Single linked list questions

26. Given a pointer to node in linked list, no start pointer is given,

27. how would you delete the node ??     

28. To detect a loop in linked list? How many ways can you do that       

29. Find the middle node in the linked list                                                                          

30. In binary search tree parent pointer is given, given is pointer to 2 nodes, find their least common successor. If we go up the tree its a Y shape linked list question, not a tree question.

31. What is 1 and 2's complement

32. How is -1 stored in computer

33. What is masking?

34. What is IP fragmentation? How will you assemble and identify packets which are fragmented?

35. What are storage classes in C

36. What are volatile variables, when to use them

37. How will you make blocking call in C

38. What does FD_ISSET do

39. How will you send a RAW IP packet

40. How will you send a RAW MAC packet

41. When PF_PACKET is used

42. What is difference between hub and bridge

43. Can gdb be used to debug inline functions? How

44. What are ICMP redirects?

45. What is active and passive ftp? Which ftp will work when we are behind a NAT machine (compression fails behind a NAT machine and we have a separate function to bypass such packets, nat_adm_ctrl)

46. What is port forwarding

47. When to use SNAT and DNAT

48. What happens when we open a web page in terms of packet and OSI flow

Cisco Placement Paper

Aptitude Questions :
1. Find perimeter of a trapezium with 3 sides given and distance between parallel sides given.

2. A triangle ABC is given, a line DE is paralel to base side and that cuts the triangle. The ratio of area of triangle to the area of trapezium .given DE/BC=3/5.

3. Four concentric circles are given. The radius of 1st circle is x.next is 2x,then 3x and 4x. given that area b/w 2nd and 1st is A and 4th and 3rd circles being B.find ratio of A to B

4. What is the Difference between the perimeteres of two concentric circles is 66. Find the difference between radius ?

5. 3/p=6,3/q=15. Find p-q

CISCO Technical Questions :

6. #define clrscr() 100
main()
{
clrscr();
printf(?%d?,clrscr());
} 

7. which of the followin is used for avoiding network congestion
a. bufferin 
b. cachin 
c. sourcequench
d. all of de above

8. main()
{
int a;
printf(?%d?,scanf(%d,&a));
}
wats o/p of this pgm. What will b printed
ans :0

9. main()
{
printf(?as?); 
printf(?\bhi?); 
printf(?is\n?);
} wat will b printed.

10. main()
{
unsigned short a=-1;
unsigned char b=a;
printf(?%d %d ?,a,b);
}
wat is o/p of the program
a. 65535 -1
b. 65535 65535
c. -1 -1 

11. arrays base address is 1000?.array is a[5][4]..then what is the correct address of a[4][3]?
ans:1056

12. one packet is 64bytes..no of pkts send is 16000..then total no of bytes send is 
ans 1024000


13. main()
{
int *i;
int s=(int *)malloc(10*sizeof(int));
for (i=0;i<10;i++)
{
printf(?%d?,i*i)
}
whats the output?
14. #define a 3+3
#define b 11-3
main()
{
printf(?%d?,a*b);
}
wat is o/p?????

15. A question in which segment address is given. logical address is 800. Base addresses also given. You have 2 find physical address

16. There was a question on processor speed in nanocycles. Then it performs a instruction in x cycles. like this..

17. #define maxval 5 (programming / computer science engineering technical questions)
int main (void)
{
int i=1;
if(i-maxval)
{
printf(?inside?);
}
else
{
printf(?out?); 
}
find o/p???


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Cisco Interview Question Part-1

Cisco Interview Questions

Kindly find below the most frequently interview question from the c programming, Operating system, networking asked in various company.
Here the below listed question asked in Cisco. We hope it will help you to crack interview.  

C Programming

+++++++++++++

1.Program to insert a node in a linked list in a sorted manner.

2.Search and delete a node from linked list based on data value.

3.Program to reverse the linked list and display the reversed linked list nodes.

4.Program to swap the 2 nibbles of a byte size variable.

5.Program to count the number of SET bits in an integer.

6.Program to swap two variables without using 3rd variable.

7.Allocating memory for a 2D array where number of rows and columns is dynamically decided.

8.What are the contents of argc and argv[]?

9.What is the difference between array of pointers and pointer to an array. Write the declarations.

10.Strcpy, strncpy, strcat etc.

11.What is the difference between array of pointers and pointer to an array. Give example of usage.

12.Program to implement strcat() or strstr() equivalents in your own program

Operating System

++++++++++++++++

1.What are the various segments of RAM memory and their significance/usage?

2.IOS versus Linux - important points.

3.What are PP processes in IOS?

4.What is flat memory architecture?

5.Is IOS an RTOS?

6.What is stack corruption? Given example.

7.What is the difference between Mutex and Semaphore?

8.Write a sample program having two processes using semaphore to synchronize the access to a common resource. Use a C structure as the shared resource.

9. Write a sample program having 2 processes communicating using message queues.

10. fork(), exec(), signal() calls – what do they do? Give examples in pseudo code

Networking

++++++++++

1.What are the important contents of IP header, MAC header, MPLS header?

2.What are ARP and gratuitous ARP?

3.How does ping work?

4.How does Trace-route work?

5.What does an ARP table look like? Contents?

6.What is a routing table? What does it look like?

7.What is the role of routing protocols like OSPF/IS-IS/BGP?

8.What is MTU and MRU significance?