Cable Tester Interview Questions And Answers

Open System Interconnection, the name itself suggest that it is a reference model which defines how applications can communicate with each other over a networking system.

It also helps to understand the relationship between networks and defines the process of communication in a network.

It is the lowest layer of TCP/IP model. It transfers the packets between different hosts. It includes encapsulation of IP packets into frames, mapping IP addresses to physical hardware devices etc.

NIC stands for Network Interface Card. It is also known as Network Adapter or Ethernet Card. It is in the form of add-in card and is installed in a computer so that the computer can be connected to a network.

Each NIC has a MAC address which helps in identifying the computer on a network.

Using shared infrastructure over an intranet, suppliers, customers, and partners are connected using dedicated connections.

OSI model stands for Open System Interconnection It is a framework which guides the applications how they can communicate in a network.

OSI model has seven layers. They are listed below,

☛ Physical Layer (Deals with transmission and reception of unstructured data through a physical medium)
☛ Data Link Layer (Helps in transferring error-free data frames between nodes)
☛ Network Layer (Decides the physical path that should be taken by the data as per the network conditions)
☛ Transport Layer (Ensures that the messages are delivered in sequence and without any loss or duplication)
☛ Session Layer (Helps in establishing a session between processes of different stations)
☛ Presentation Layer (Formats the data as per the need and presents the same to Application layer)
☛ Application Layer (Serves as the mediator between Users and processes of ap

The physical medium or the communication path through which the devices are connected in a network is called as a Link.

Data transferring which takes place only in one direction is called Simplex. In Simplex mode, the data gets transferred either from sender to receiver or from receiver to sender.

Eg: Radio signal, the print signal given from computer to printer etc.

In Ring Topology, each device of the network is connected to two other devices on either side which in turn forms a loop. Data or Signal in ring topology flow only in a single direction from one device to another and reaches the destination node.

The advantage of ring topology is that it can be installed easily. Adding or deleting devices to the network is also easy. The main disadvantage of ring topology is the data flows only in one direction. And a break at a node in the network can affect the whole network.

A network can be certified as an effective network based on below-mentioned points,

☛ Performance: A network’s performance is based on its transmitted time and response time. The factors affecting the performance of a network are hardware, software, transmission medium types and the number of users using the network.
☛ Reliability: Reliability is nothing but measuring the probability of failures occurred in a network and the time taken by it to recover from it. The factors affecting the same are the frequency of failure and recovery time from failure.
☛ Security: Protecting the data from viruses and unauthorized users. The factors affecting the security are viruses and users who do not have permission to access the network.

Test cases are not always straight-forward and QA Engineers will need to act on their personal judgement. They need to feel comfortable with ambiguity.

Data transmitted through the networks’ comes in different ways like text, audio, video, images, numbers etc.

☛ Audio: It is nothing but the continuous sound which is different from text and numbers.
☛ Video: Continuous visual images or a combination of images.
☛ Images: Every image is divided into pixels. And the pixels are represented using bits. Pixels may vary in size based on the image resolution.
☛ Numbers: These are converted into binary numbers and are represented using bits.
☛ Text: Text is also represented as bits.

In Bus Topology, all the devices of the network are connected to a common cable (also called as the backbone). As the devices are connected to a single cable, it is also termed as Linear Bus Topology.

The advantage of bus topology is that it can be installed easily. And the disadvantage is that if the backbone cable breaks then the whole network will be down.

This deals with how the computers or nodes are arranged in the network. The computers are arranged physically or logically.

The devices or the computers connected to the links are named as nodes.

Size of the Network is defined as the geographic area and the number of computers covered in it. Based on the size of the network they are classified as below,

Based on the size of the Network they are classified as below,

☛ Local Area Network (LAN): A network with a minimum of two computers to a maximum of thousands of computers within an office or a building is termed as LAN.Generally, it works for a single site where people can share resources like printers, data storage etc.
☛ Metropolitan Area Network (MAN): It is larger than LAN and used to connect various LAN’s across small regions, a city, campus of colleges or universities etc which in turn forms a bigger network.
☛ Wide Area Network (WAN): Multiple LAN’s and MAN’s connected together form a WAN. It covers a wider area like a whole country or world.

It is more complex than LAN and covers a large span of area typically a large physical distance. The Internet is the largest WAN which is spread across the world. WAN is not owned by any single organization but it has distributed ownership.

Ipconfig stands for Internet Protocol Configuration and this command is used on Microsoft Windows to view and configure the network interface.

The command ipconfig is useful for displaying all TCP/IP network summary information currently available on a network. It also helps to modify the DHCP protocol and DNS setting.

Ifconfig (Interface Configuration) is a command that is used on Linux, Mac, and UNIX operating system. It is used to configure, control the TCP/IP network interface parameters from CLI i.e. Command Line Interface. It allows you to see the IP addresses of these network interfaces.

Domain Name Server (DNS), in a non-professional language and we can call it as Internet’s phone book. All the public IP addresses and their hostnames are stored in the DNS and later it translates into a corresponding IP address.

For a human being, it is easy to remember and recognize the domain name, however, the computer is a machine that does not understand the human language and they only understand the language of IP addresses for data transfer.

There is a “Central Registry” where all the domain names are stored and it gets updated on a periodic basis. All the internet service providers and different host companies usually interact with this central registry to get the updated DNS details.

This is the top layer in TCP/IP model. It includes processes which use Transport Layer Protocol to transmit the data to their destination. There are different Application Layer Protocols such as HTTP, FTP, SMTP, SNMP protocols etc.

Network Topology is a physical layout of the computer network and it defines how the computers, devices, cables etc are connected to each other.

☛ #1) Physical Layer (Layer 1): Physical Layer converts data bits into electrical impulse or radio signals. E.g. Ethernet.

☛ #2) Data Link Layer (Layer 2): At Data Link layer, data packets are encoded and decoded into bits and it provides a node to node data transfer. Data Link Layer also detects the errors occurred at Layer 1.

☛ #3) Network Layer (Layer 3): Network Layer transfers variable length data sequence from one node to another node in the same network. This variable length data sequence is also known as “Datagrams”.

☛ #4) Transport Layer (Layer 4): It transfers data between nodes and also provides acknowledgment of successful data transmission. It keeps track of transmission and sends the segments again if the transmission fails.

OSI Reference Model

☛ #5) Session Layer (Layer 5): Session Layer manages and controls the connections between computers. It establishes, coordinates, exchange and terminates the connections between local and the remote applications.

☛ #6) Presentation Layer (Layer 6): It is also called as “Syntax Layer”. Layer 6 transforms the data into the form in which the application layer accepts.

☛ #7) Application Layer (Layer 7): This is the last layer of OSI Reference Model and is the one which is close to the end user. Both end-user and application layer interacts with the software application. This layer provides services for email, file transfer etc.

Through Transmission the data gets transferred from source to destination (Only one way). It is treated as the physical movement of data.

Communication means the process of sending and receiving data between two media (data is transferred between source and destination in both ways).

Sending one copy of data from a single sender to multiple clients or receivers (selected clients) of the networks which are in need of such data.

In this type of network, a central server is located to store the data, applications etc of the clients. The server computer provides the security and network administration to the network.

Often times within the QA process, test cases fail. But why are they failing? This can be tricky. A great QA engineer is able to provide exact reasons to the developer, rather than simply saying a test case “failed”.