Cisco interview questions for freshers

Last Updated on August 22, 2022 by Gokul Kannan

Thousands of job seekers apply every year to Cisco where their skills are tested and thoroughly. Here we will be discussing some of the important questions that were commonly asked in Cisco interview.

1. What is an IP access list and what are its features?
Ans. IP access list is a set of rules for controlling the traffic in network and reducing the chances of attacks. This list is used to filter traffic based on rules defined for incoming and outgoing network. The standard list features are given by

• Provide bandwidth control
• Provide NAT control
• Trigger dial-on-demand
• Control access to vty
• Block Unwanted traffic
• Authenticate rsh and rcp
• Limit Debug command output

2. Which layer is responsible for identifying and establishing the availability of the Intended Communication Partner?
Ans. Application layer is responsible for establishing the connection with Communication partner.

3. In the following code snippet how many times it will print “Hello” –

main()
   { fork();
     fork();
     fork();
     printf("hello");
   }

Ans. The number of hello printed is given by number of fork() is called as – 23=8 times.

4. What are bridges and which layer they are used int?
Ans. Bridges connect two parts of the same network. It operates in the Data-Link layer of the OSI model and can distinguish local and remote data so travelling from one service to another.
It can also connect LAN segments to new LAN segments.

5. Can you write the output of the following program?

#include<stdio.h>
 #define mmx 10+10
 int main()
   { 
   printf("%d",mmx*mmx);
return 0;
   }

Ans. 120 which is got by 10+10*10+10 = 120.

6. What are the conditions for deadlock?
Ans. The following conditions if satisfied then the process is considered to be in deadlock –

• Mutual Exclusion: When two process share same resource and both of the process are different then each of them wait for the other to utilise the resource.
• Hold and Wait: When two resources wait for each other and do not get executed.
• No pre-emption: This means we cannot force stop or remove one process among the waiting processes.
• Circular Wait: When a process is waiting for a resource being hold by another process which is again waiting for a resource hold by the first one, this cyclic wait is called circular wait. This leads to deadlock.

7. What is a firewall?
Ans. Firewall is device or layer placed between safe and unsafe networks which regulates the access and of unauthorised users and authorised users. It provides a filter to prevent unauthorised changes to the network.

8. What are the different memories used in Cisco router?
Ans. Three types of memories are used in a Cisco router –

• DRAM: configuration file which gets executed
• NVRAM: start-up configuration file
• Flash Memory: Cisco IOS.

9. Explain IP address to a layman.
Ans. Each computer connected to the internet has a unique number assigned which distinguishes its presence in the network. This number is referred as IP address. If a computer does not have one then it won’t be able to communicate with other computers in the network.

10. What are the features of Object-Oriented Programming Language?
Ans. The following features of OOP are –
Polymorphism: Multiple forms of a function can be used.

• Abstraction: Important parts of the program are hidden from general user.
• Isolation: In OOP, isolation is performed using wrapping the members into a class and having access specifiers to change their scope of access in the program.
• Encapsulation: Classes are used to wrap up data and member functions into modules, this is called encapsulation.

11. Do you know what is a Gateway?
Ans. A gateway is node which is considered as an entrance for requests and responses to some services. It is different than default gateway.

12. What is routing?
Ans. Routing is basically the process of creating routes for the data packets to be transferred from one source to destination. It is done with a router and we can easily select routes in the network traffic across multiple networks.

This article explained about the important Cisco interview questions for freshers. To practice more problems you can check out MYCODE | Competitive Programming.