Wireless engineer interview questions
A recruiter from Atlanta submitted this set of questions for interviewing at a wireless equipment company.
Describe your home WLAN setup.(Pay attention to candidate’s confidence. Plus if the candidate built it himself. Plus if the network is secured additionally, regardless of the protocols used. Plus if the candidate fought poor coverage.)
Ad-hoc vs. infrastructure topology. Advantages and disadvantages. Ad-hoc networks are easy to set up. By definition ad-hoc WLANs do not require access point, so they are cheaper. With infrastructured WLANs one can connect to wired LAN, enable wireless roaming for office workers, centralize WLAN management, boost the range.
Your preferred brand for wireless cards and access points. (An experienced candidate will be able to come up with strong argument to defend his preferences. He will point to the past projects as well.) Read more…
CCNA/Cisco admin interview questions
You need to retrieve a file from the file server for your word processing application, which layer of the OSI model is responsible for this function?
You are working in a word processing program, which is run from the file server. Your data comes back to you in an unintelligible manner. Which layer of the OSI model would you investigate?
Interview questions for network engineer
Describe the OSI model.
What is the difference between a repeater, bridge, router? Relate this to the OSI model.
Describe an Ethernet switch and where it fits into the OSI model.
What is a VLAN? What is an ELAN? What is the difference?
Relate FDDI/ATM/SONET to the OSI model.
Explain how to configure a host network interface (e.g. IP address, netmask, broadcast address)? Read more…
Windows admin interview questions
Describe how the DHCP lease is obtained. It’s a four-step process consisting of (a) IP request, (b) IP offer, © IP selection and (d) acknowledgement.
I can’t seem to access the Internet, don’t have any access to the corporate network and on ipconfig my address is 169.254.*.*. What happened? The 169.254.*.* netmask is assigned to Windows machines running 98/2000/XP if the DHCP server is not available. The name for the technology is APIPA (Automatic Private Internet Protocol Addressing).
We’ve installed a new Windows-based DHCP server, however, the users do not seem to be getting DHCP leases off of it. The server must be authorized first with the Active Directory.
How can you force the client to give up the dhcp lease if you have access to the client PC? ipconfig /release
What authentication options do Windows 2000 Servers have for remote clients? PAP, SPAP, CHAP, MS-CHAP and EAP. Read more…
Networking interview questions
Q1. Name of seven layers in Open System Interconnection model.
A. They are Application, Presentation, Session, Transport, Network, Data link, and Physical.
Q2. What is the time complexity of matrix multiplication ?
void Mult_Matrix(matrix A, matrix B, matrix C)
int i, j, k;
for ( i = 1; i < N; i++)
for ( j = 1; j < N; j++ )
C[i][j] = 0;
for ( k = 0; k < N; k++ )
C[i][j] = A[i][j]*B[k][j];
A. The time comlexity of matrix mulitiplication is O(N^3)
Q3. What is the null pointer in C++ ?
A. The null pointer is a special C++ pointer value that can be used for any pointer that doesn’t pointer anywhere. It can be written as the constant NULL form stlib.h
Q4. What is the goal of the shortest distance algorithm ?
A. The goal is to completely fill the distance array so that for each vertex v, the value of distance[v] is the weight of the shortest path from start to v.
Q5. What is the difference between an abstract class and an interface?
An abstract class may have fields and some implemented methods.
An interface has no implementation; only constants and method declarations
Networking and protocols interview questions
Q: What are the seven layers of the OSI model?
A: The layers are physical, data link, network, transport, session, presentation, and application layers.
Q: In the TCP client-servel model, how does the three-way handshake work in opening connection?
A: The client first sends a packet with sequence “x” to the server. When the server receives this packet, the server will send back another packet with sequence “y”, acknowledging the request of the client. When the client receives the acknowledgement from the server, the client will then send an acknowledge back to the server for acknowledging that sequence “y” has been received.
Q: What is the purpose of exchanging beginning sequence numbers during the the connection in the TCP client-server model?
A: To ensure that any data lost during data transfer can be retransmitted.
Q: How does Asynchronous Transfer Mode (ATM) work?
A: ATM works by transmitting all traffic in small, fixed-sized cells. These small, fixed-size cells reduces queuing delay and can be switched quickly. ATM fits into layer 2 of the OSI model and provides functions for framing and error correction. At the port interface, ATM switches convert cells into frames, and vice versa. ATM provides Quality of Service and traffic shaping.
Q: Given a Class B Network with subnet mask of 255.255.248.0 and a packet addressed to 188.8.131.52, what is the subnet address?
A: Take the 2 addresses, write them in binary form, then AND them. The answer is 130.40.32.
Network engineer/architect interview questions
Explain how traceroute, ping, and tcpdump work and what they are used for?
Describe a case where you have used these tools to troubleshoot.
What is the last major networking problem you troubleshot and solved on your own in the last year?
What LAN analyzer tools are you familiar with and describe how you use them to troubleshoot and on what media and network types.
Explain the contents of a routing table (default route, next hop, etc.)
What routing protocols have you configured?
Describe the commands to set up a route.
What routing problems have you troubleshot?
How do you display a routing table on a Cisco? On a host? Read more…
Network programming interview questions
Question 1: How does the race condition occur?
It occurs when two or more processes are reading or writing some shared data and the final result depends on who runs precisely when.
Question 2: What is multiprogramming?
Multiprogramming is a rapid switching of the CPU back and forth between processes.
Question 3: Name the seven layers of the OSI Model and describe them briefly.
Physical Layer – covers the physical interface between devices and the rules by which bits are passed from one to another.
Data Link Layer - attempts o make the physical link reliable and provides the means to activate, maintain, and deactivate the link. Read more…
Networking and Unix interview questions
What is UTP?
UTP – Unshielded twisted pair 10BASE-T is the preferred Ethernet medium of the 90s. It is based on a star topology and provides a number of advantages over coaxial media:
It uses inexpensive, readily available copper phone wire. UTP wire is much easier to install and debug than coax. UTP uses RG-45 connectors, which are cheap and reliable.
What is a router? What is a gateway?
Routers are machines that direct a packet through the maze of etworks that stand between its source and destination. Normally a router is used for internal networks while a gateway acts a door for the packet to reach the ‘outside’ of the internal network
What is Semaphore? What is deadlock?
Semaphore is a synchronization tool to solve critical-section problem, can be used to control access to the critical section for a process or thread. The main disadvantage (same of mutual-exclusion) is require busy waiting. It will create problems in a multiprogramming system, where a single CPU is shared among many processes. Read more…