Refer to the below industrial networking and wireless interview questions with answers.
Voltages swing between 0 and -2.05 volts on coaxial cables or between -2.5 V to +2.5 V on twisted pair.
It is a rule to find the maximum transmission path in a network.
It stands for 5 segments-4 repeaters-3coax segments-2 link segments.
Repeater delay, cable delay, NIC delays and safety factor.
The sum of these delays must be less than 2.56 microseconds for healthy transmission.
Industrial network require fast response and real-time operation, while Ethernet does not require same response.
Security is another concern where industrial network is split off from commercial networks. Industrial network are also partitioned into sub-networks for these reasons.
Problems attributed to either cabling, the LAN devices, the NIC or the protocol stack configuration on the hosts.
Ultra-high frequency (mid and low); Very high frequency (high, mid, low); High frequency
A network is a set of devices (referred to as nodes) connected by media links.
A node can be a computer, printer, or any other device capable of sending or/receiving data generated by other nodded on the network. The links connecting the devices are called as communication channels.
Line configuration refers to the way two or more communication devices attach to a link.
A link is the physical communication pathway that transfers data from one device to another.
Topology refers to the way a network is laid out, either physically or logically. Two or more devices connect to a link; two or more links forms a topology.
The different types of topology are,
Peer-to-peer is one where the devices share the link equally.
Primary-secondary is one where one device controls traffic and the others must transmit through it.
Active hub:-
The central hub in the tree is an active hub. An active hub contains a repeater, which is hardware device that regenerates the received bit patterns before sending them out.
A passive hub provides a simple physical connection between the attached devices.
Transmission mode is used to define the direction of flow between two linked devices. There are three types of transmission modes;
The communication is unidirectional, as on a one-way street. Only one of the two stations on link can transmit; the other can only receive.
Each station can transmit and receive but not at the same time. When one device is sending the other can only receive, and vice versa.
Both stations can transmit and receive simultaneously.
A LAN is usually privately owned and links the devices in a single office, building or campus. LANs are designed to allow resources to be shared between personal computers are workstations.
A MAN is designed to extend over an entire city. It may be a single n/w such as a cable tv n/w, or it may be means of connecting a number of LANs into a larger network so that resources may be shared LAN-to-LAN as well device-to-device.
WAN provides long distance transmission of data, voice, image and video information over large geographical areas that may comprise a country, or even the whole world.
A open system model is a model that allows any two different systems to communicated regardless of their underlying architecture.
It is a layered frame work for the design of network systems that allows for communication across all types of computer systems. It is built of seven ordered layers. They are,
The initiator first transmits a frame called an enquiry asking if the receiver is available to receive data.
The receiver must answer either with an acknowledgement frame if it is ready to receive with negative acknowledgement.
Flow control refers to a set of procedures used to restrict the amount of data the sender can send before waiting for acknowledgment.
In the stop and wait method of flow control sender sends one frame and waits for an acknowledgement before sending the next frame.
In the sliding window flow control; the sending of data is constrained by imaginary window that expands and contracts according to the acknowledgement received by the sender.
Error control in the data link layer is based on the automatic repeat request which means re-transmission of data in three cases: damaged frame lost frame, lost acknowledgment.
A poll is sent to the secondary device by the primary to determine if the secondary has to send. Thesecondary can respond by sending a acknowledgement or a data frame.
A select frame is sent from the primary device to the secondary device to tell the secondary to prepare toreceive data. The secondary responds with an ACK or a NAK.
A protocol in data communications is the set of rules used to implement one or more layers of the OSI model.
Data transparency in data communication means we should be able to send any combination of bits as data. The combination of bits as data is not confused with the control information.
Binary synchronous communication is a well-known character oriented protocol.
BSC operates in half-duplex mode using stop and wait ARQ in a point to –point or multipoint configuration.
Bit stuffing is the process of adding one extra ‘0’ whenever there are five consecutive ‘1’s in the data.
So that the receiver doesn’t mistake the data for a flag.
High-level data link control is a bit oriented data link designed to support both half-duplex and full duplex communication over point-to point and multi point links.
Piggy backing means combining data to be sent and acknowledgement of the frame received in one single frame.
A repeater or regenerators is an electronic device that operates on only physical layer of the OSI model.
A repeater installed on a link receives the signal before it becomes too weak or corrupted. Regenerates the original bit pattern and puts the refreshed copy back onto link.
It is operate on the physical layer and data link layers of the OSI model. Bridges can divide a large network into the small segments. They can also relay frames between two originally separate LANs.
Bridges contain logic that filters traffic, thus making them useful for controlling congestion and isolating problem links.
These have access to network layer address and contain software that enables them to determine which of several possible paths between those addresses in the best for a particular transmission.
Routers operate in the physical, data link and network layers of the OSI model.
A gateway is a protocol converter.
A gateway can accept a packet formatted for one protocol and convert into a packet formatted for another protocol before forwarding it.
A gateway potentially operates in all seven layers of the OSI model. A gateway is a protocol converter.
A gateway by itself can accept a packet formatted for one protocol & convert it to a pocket formatted for another protocol before forwarding it.
A network is a set of devices often referred to as nodes, connected by media link.
A node can be a computer, printer or any device capable of sending and or receiving data generated by other nodes on the network. The links connecting the devices are often called communication channels.
When two are networks are connected they become an internetwork or internet. Individual network are joined into internetworks by the use of internetworking devices.
These include routers and gateways. The word internet means an interconnection of networks and is world-wide network.
It involves a method in which router may select a new route for each packet in response to changes in condition and topology of the networks.
Once the path way towards a destination has been selected, the router sends all the packets to that destination along that one route.
So the routing destinations are not made based on the condition or topology of the network.
Each router periodically shares its knowledge about the entire network with its neighbors.
Periodically sends its knowledge about the network only to those routers to which it has direct links. Information sharing occurs.
In link state routing each router shares its knowledge of its neighborhood with every other router in their internetwork.
Each router sends out information about the neighbors when there is a change.
Each router sends the information to every other router on the internet working not just to its neighbors.
It does so by a process called flooding.Flooding means that a router sends its information to all of its neighbors.
Two LANs may be connected by more than one bridge. In this case, if the bridges are transparent bridges, they may create a loop, which means a packet may be going round, from one LAN to another and back again to the first LAN.
To avoid this situation bridges today use what is called the spanning tree algorithm.
It operates at 100 Mbps. With new applications such as computer aided design, image processing and real time audio and video being implemented on LANs.
It has a data rate of 1000Mbps. It is used in optical fiber, although the protocol does not eliminate the use of twisted pair cables.
10 BASE 5: Thick Ethernet; 10 BASE 2: Thin Ethernet.; 10 BASE T: Twisted pair Ethernet Fast Ethernet, Gigabit Ethernet, Switched Ethernet.
Advantages- Many devices to be attached to a single central hub, Allows the networks to isolate
A routing table has columns for at least three types of information: the network ID and ID of the next router. The network ID is the final destination of the packet.
The cost is the number of hops a packet must make packet to get there. And the next router is the router is the router to which a packet must be delivered on its way to a particular destination.
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