Statistics Show That The Demand For Wireless Network Engineers Is Growing. Because Companies Tend To Implement In-House Networks With The Least Hassle, They Are Reluctant To Let Different Types Of Ducts And Cables Pass-Through The Edges Of Walls So Clients Can Communicate With The Network.
For this purpose, they prefer to hire a wireless network engineer to manage the work from start to finish and maintain the network after commissioning. In addition, large network service companies have to hire engineers familiar with wired and wireless LANs to do business.
The critical question is how to hire a Carbold Wireless Network Engineer? You have to ask the seven questions in this article and ask the candidates to provide a technical and comprehensive answer to each in simple language. You do not need to prepare a long list of questions and take a few hours for each interview.
If the answers were comprehensive and accurate, you have found the person.
A good job market for wireless network engineers
To find a suitable job in this field that suits your skills and expertise, you must first appear in a proud job interview. It is possible that you have all the essential qualifications required in this field and even have experience working with wireless equipment and designing wireless LANs, have high analytical skills in problem-solving, and in a word, are an expert in this field. Be in the area. However, if you are not prepared for the employers’ questions, you will miss out on a great opportunity.
Depending on the company or organization you intend to enter, if you are lucky, the interview will start with a few simple questions, But meaningful life opportunities can not easily miss with such a mindset.
To get general information about the questions that you may encounter in the interview session, in this article, we will get acquainted with seven essential questions that most wireless network engineers will answer in the interview sessions. We have also provided short answers to help readers increase their chances of success in interviews.
1. Explain the difference between IBSS, BSS, and ESS.
The Basic Service Set (BSS) refers to stations that can communicate with each other in the physical layer of the OSI model. Each BSS is identified by a BSSID, the Wi-Fi chip address of a wireless access point (WAP) chip that serves the BSS. IEEE 802.11 defines the basic service suite as wireless LAN building blocks. These blocks consist of essential services composed of fixed or mobile wireless stations and an optional central base station known as an access point.
Independent Basic Services (IBSS) The Independent BSS is a temporary form of BSS that cannot be connected to other essential services because it does not contain any access points. In other words, it can not link to any additional basic service suite.
Extended Service Set (ESS) The Extended Service Set includes essential services that are access points and interconnected by a distribution system. An extended service suite combines two or more BSSs with an access point.
In this case, the BSSs are connected through a distribution system that is a wired or wireless network. In the above architecture, the system distributes the exponents in the BSSs. It should note that the developed service suite uses two types of stations that are mobile and fixed. Mobile Stations Typical stations are within a BSS. Fixed stations are access point stations that are part of a wired LAN.
A wireless network engineer must have in-depth knowledge to answer these questions and provide a complete explanation with examples for each concept.
2. Explain the difference between WLAN and WiMAX
Wireless Local Area Network (WLAN) provides a connection between WLAN-compatible devices based on the protocol supported by the network. Wireless LANs support the 802.11 standards set by the Institute of Electrical and Electronics Engineers (IEEE), such as 11a, 11b, 11g, 11n, 11ac, and 11 ad.
On the other hand, WiMAX is used as a broadband network to connect various wireless devices. WiMAX supports IEEE 16d and IEEE e16 standards.
To answer these two questions, you must have in-depth knowledge of standards, channels, frequency bands, frequency distortion, security, etc. In other words, to answer these two questions, you need to have hands-on experience and in-depth study of wireless network architecture to be able to describe problems and provide solutions to them.
Hiring managers are strict about sensitive job positions, such as wireless network engineers. In most cases, they do not easily hire people who submit resumes and ask technical and micro-questions. Now that you are familiar with the two simple questions in this area, it is better to get acquainted with the other two more complex questions.
3. Explain the DSSS and CCK modulation schemes.
Direct Sequence Spread Spectrum (DSSS) and Complementary Code Keying (CCK) refer to WLAN modulation schemes that comply with IEEE 802.11b.
In DSSS systems, PN codes modulate data bits and allow all system bandwidth to be available to users. DSSS is a modulation in which data streams are divided into small chunks called chips. Chips are distributed simultaneously on all frequencies in one of the three wide channels. In this architecture, sharing and encrypting data is called “chipping.” The distribution rate used to transmit information is also called “chip code,” which is unique to each device.
CCK was introduced in 1999 as an alternative to Barker code in wireless digital networks because CCK uses bit sequences more efficiently and can use them more efficiently. CCK is capable of transmitting more data per unit for signal bandwidth.
As you might have guessed, a wireless network engineer should have enough knowledge about these technologies and the security challenges and vulnerabilities that cause hackers to attack wireless networks.
4. Explain why TCP / IP and OSI stacks are different.
TCP / IP (Transmission Control Protocol / Internet Protocol) and OSI (Open System Connection) models have different layers. TCP / IP is a four-tier standard designed for Internet applications. On the other hand, OSI is a seven-tier network protocol architecture standard. OSI is a public stack that allows different devices to communicate with each other without any problems and allows free access to protocols. In the TCP / IP model, the network access layer is compatible with the OSI model’s physical and data link layers.
Experienced network experts know that understanding how these two protocols and sub-protocols work, especially TCP / IP, widely used in communication networks today, requires several months of in-depth study and practical work. A networking expert can provide a comprehensive but straightforward explanation of how information is transmitted by the layers of each of these protocols, headers, flags, and other details of these layers.
More advanced interview questions
If you are applying for a wireless network engineer position, you need to prepare yourself for more challenging technical questions. Three of these questions are as follows:
5. Describe the basic instructions for implementing CAPWAP.
Control and Provisioning of Wireless Access Points (CAPWAP) The title Control and Provisioning of Wireless Access Points is a standard network protocol that allows central wireless LAN access control to manage wireless access points. The CAPWAP protocol creates special communication tunnels to exchange traffic between access points and wireless LAN controllers. The CAPWAP protocol is based on the LWAPP protocol called Lightweight Access Point. The protocol allows the wireless LAN controller to control wireless access points. It should note that LWAPP-compliant access points can find and connect to the CAPWAP controller.
To implement CAPWAP, you must first configure the firewall settings correctly. The first thing to consider is whether firewall configurations only allow traffic to be transferred from access points that use the LWAPP protocol. If the answer is yes, you need to adjust the firewall to allow access to CAPWAP access points. Next, enable the CAPWAP protocol ports 5246 and 5247 UDP. The goal is that if access control lists (ACLs) block the control path between access points and the controller, by opening new protocol ports, you can allow access point traffic to clients.
6. Explain how WLC works when checking packet transfers
An LWAPP packet encapsulates all 802.11 packets and sends them to the Wireless LAN Controller (WLC) named Wireless LAN Controller. Note that WLC works based on the destination IP address, so if the destination is a wireless client, the packet will be encapsulated and sent to the wireless client before reaching LWAPP. If the goal is on a wired network, LWAPP switches the 802.11 headers to the Ethernet header, sending the packet to the network switch to eventually reach the wired client. WLC removes the Ethernet header when a box arrives from the wired network, replaces it with an 802.11 title, and adds LWAPP header information. Finally, the package is encapsulated and sent to the wireless client.
7. In WLAN, what messages are exchanged between AP and STA, and what are the functions of each?
Access points are devices that play an essential role in improving the performance of wireless and wired networks. Various messages are exchanged between access points and stations on a wireless LAN for multiple purposes, including connection, data transfer, termination, and more. Here are some WLAN MAC messages along with their primary function.
- Association response: Sends the access point of this message in response to receiving the connection request.
- Association request: The station sends this message to the access point after authentication to get the connection.
- Authentication: The station requests authentication with this message.
- De-authentication: An authentication station uses this message to indicate that the recipient no longer needs authentication.
- Probe request: This message is sent on the wireless LAN to find the access point.
It would help if you had enough time to answer the wireless network engineer interview questions. While you may use your experience as a wireless network engineer to answer questions like the ones above, you still need to be able to summarize your answers concisely and straightforwardly. Therefore, I suggest that you read the questions in this article carefully because you must have a comprehensive study to answer each of these questions.