Basic Networking Interview Questions
What is Piggy Backing?
A technique called piggybacking is used to improve the efficiency of the bidirectional protocols. When a frame is carrying data from A to B, it can also carry control information about arrived (or lost) frames from B; when a frame is carrying data from B to A, it can also carry control information about the arrived (or lost) frames from A.
What is Pipelining ?
In networking and in other areas, a task is often begun before the previous task has ended. This is known as pipelining.
What is point-point link?
If the physical links are limited to a pair of nodes it is said to be point-point link.
What is point-to-point protocol?
A communications protocol used to connect computers to remote networking services including Internet service providers.
What is Project 802?
It is a project started by IEEE to set standards to enable intercommunication between equipment from a variety of manufacturers. It is a way for specifying functions of the physical layer, the data link layer and to some extent the network layer to allow for interconnectivity of major LAN protocols.It consists of the following:
- 802.1 is an internetworking standard for compatibility of different LANs and MANs across protocols.
- 802.2 Logical link control (LLC) is the upper sublayer of the data link layer which is non-architecture-specific, that is remains the same for all IEEE-defined LANs.
- Media access control (MAC) is the lower sublayer of the data link layer that contains some distinct modules each carrying proprietary information specific to the LAN product being used. The modules are Ethernet LAN (802.3), Token ring LAN (802.4), Token bus LAN (802.5).
- 802.6 is distributed queue dual bus (DQDB) designed to be used in MANs.
What is Protocol Data Unit?
The data unit in the LLC level is called the protocol data unit (PDU). The PDU contains of four fields a destination service access point (DSAP), a source service access point (SSAP), a control field and an information field. DSAP, SSAP are addresses used by the LLC to identify the protocol stacks on the receiving and sending machines that are generating and using the data. The control field specifies whether the PDU frame is a information frame (I – frame) or a supervisory frame (S – frame) or a unnumbered frame (U – frame).
What is Protocol?
A protocol is a set of rules that govern all aspects of information communication.
What is Proxy ARP?
It is using a router to answer ARP requests. This will be done when the originating host believes that a destination is local, when in fact is lies beyond router.
What is RAID?
A method for providing fault tolerance by using multiple hard disk drives.
What is redirector?
Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.
What is Redundancy?
The concept of including extra information in the transmission solely for the purpose of comparison. This technique is called redundancy.
What is region?
When hierarchical routing is used, the routers are divided into what we will call regions, with each router knowing all the details about how to route packets to destinations within its own region, but knowing nothing about the internal structure of other regions.
What is RIP (Routing Information Protocol)?
It is a simple protocol used to exchange information between the routers.
What is Round Trip Time?
The duration of time it takes to send a message from one end of a network to the other and back, is called RTT.
What is SAP?
Series of interface points that allow other computers to communicate with the other layers of network protocol stack.
What is semantic gap?
Defining a useful channel involves both understanding the applications requirements and recognizing the limitations of the underlying technology. The gap between what applications expects and what the underlying technology can provide is called semantic gap.
What is silly window syndrome?
It is a problem that can ruin TCP performance. This problem occurs when data are passed to the sending TCP entity in large blocks, but an interactive application on the receiving side reads 1 byte at a time.
What is Sliding Window?
The sliding window is an abstract concept that defines the range of sequence numbers that is the concern of the sender and receiver. In other words, he sender and receiver need to deal with only part of the possible sequence numbers.
What is SLIP (Serial Line Interface Protocol)?
It is a very simple protocol used for transmission of IP datagrams across a serial line.
What is source route?
It is a sequence of IP addresses identifying the route a datagram must follow. A source route may optionally be included in an IP datagram header.&
What is Stop-and-Wait Automatic Repeat Request?
Error correction in Stop-and-Wait ARQ is done by keeping a copy of the sent frame and retransmitting of the frame when the timer expires.
What is Stop-and-Wait Protocol?
In Stop and wait protocol, sender sends one frame, waits until it receives confirmation from the receiver (okay to go ahead), and then sends the next frame.
What is subnet?
A generic term for section of a large networks usually separated by a bridge or router.
What is Synchronous TDM?
In STDM, the multiplexer allocates exactly the same time slot to each device at all times, whether or not a device has anything to transmit.
What is TDM?
TDM is a digital process that can be applied when the data rate capacity of the transmission medium is greater than the data rate required by the sending and receiving devices.
What is terminal emulation, in which layer it comes?
Telnet is also called as terminal emulation. It belongs to application layer.
What is the difference between routable and non- routable protocols?
Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.
What is the difference between TFTP and FTP application layer protocols?
The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP.The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offer by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information.
What is the minimum and maximum length of the header in the TCP segment and IP datagram?
The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes.
What is the range of addresses in the classes of internet addresses?
Class A – 0.0.0.0 – 127.255.255.255Class B – 22.214.171.124 – 126.96.36.199Class C – 192.0.0.0 – 188.8.131.52Class D – 184.108.40.206 – 220.127.116.11Class E – 240.0.0.0 – 247.255.255.255
What is traffic shaping?
One of the main causes of congestion is that traffic is often busy. If hosts could be made to transmit at a uniform rate, congestion would be less common. Another open loop method to help manage congestion is forcing the packet to be transmitted at a more predictable rate. This is called traffic shaping.
What is usage of Sequence Number in Relaible Transmission?
The protocol specifies that frames need to be numbered. This is done by using sequence numbers. A field is added to the data frame to hold the sequence number of that frame. Since we want to minimize the frame size, the smallest range that provides unambiguous communication. The sequence numbers can wrap around.
What is virtual channel?
Virtual channel is normally a connection from one source to one destination, although multicast connections are also permitted. The other name for virtual channel is virtual circuit.
What is virtual path?
Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.
What is VRC?
It is the most common and least expensive mechanism for Error Detection. In VRC, a parity bit is added to every data unit so that the total number of 1s becomes even for even parity. It can detect all single-bit errors. It can detect burst errors only if the total number of errors in each data unit is odd.
What is WDM?
WDM is conceptually the same as FDM, except that the multiplexing and demultiplexing involve light signals transmitted through fiber optics channel.
What is wide-mouth frog?
Wide-mouth frog is the simplest known key distribution center (KDC) authentication protocol.
In token Ring , hub is called Multistation Access Unit(MAU).
When a switch is said to be congested?
It is possible that a switch receives packets faster than the shared link can accommodate and stores in its memory, for an extended period of time, then the switch will eventually run out of buffer space, and some packets will have to be dropped and in this state is said to congested state.
Which layer links the network support layers and user support layers?
The Transport layer links the network support layers and user support layers.
Which layers are network support layers?
a. Physical Layerb. Data link Layer andc. Network Layers
Which layers are user support layers?
a. Session Layerb. Presentation Layer andc. Application Layer
Why should you care about the OSI Reference Model?
It provides a framework for discussing network operations and design.