Wednesday, April 11, 2018

Networking questions for B.C.A., P.G.D.C.A. and all IT Students


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Prepared By : Preash Limbad
Contact No : 7600044051
E-Mail : rupareleducation@gmail.com


Networking questions


(1) What is a network ?
Answer: A network is the connection of two or more computers. These computers are linked together. The most common types of networks are:
(a) Local Area Networks (LANS) and
(b) Wide Area Networks (WANS).
The primary difference between the two is that a LAN is generally confined to a limited  area, whereas a WAN covers a large area. Severally connected LANS creates a WAN.
(2) Write the types of networks.
Answer: Intranet –The private LAN which is used by everyone within an organization or
Basic Networking questions and answers
company is called intranet. It might consist of an e-mail system, a message accesing  board and one or more Web site portals .
Extranet – A network  that connects people within this company with people who are outside of the company is called extranet. It happens within a secure ,password protected network.
(3) What is physical and wireless media?
Answer:- Physical media: 
·                                 Twisted pair cable – consists of two independently insulated wires twisted around each other
·                                 Coaxial cable – consists of an insulated center wire grounded by a shield of braided wire Fiber optic cable – contains hundreds of clear fiberglass or plastic fibers
·                                 ISDN line – a special digital telephone line that transmits and receives information at very high speeds
Wireless media:
·                                 Microwave system – transmits data via high-frequency radio signals through the atmosphere
·                                 Satellite system – receive signals from the earth, amplify them, and then transmit back these signals to the appropriate locations on the earth.
·                                 Cellular technology – uses antennae resembling telephone towers to pick up radio signals within a specific area
(4) What is network topologies?
Answer: Network Topology  is refers to the way computers and its peripheral environment  is configured to form networks.
·                                 Bus topology – all computers are synchronize by a single line of cable.
·                                 Star topology – multiple computers are linked to a main computer, which is called a host
·                                 Ring topology – each computer is connected to two other computers, with the entire network. It forms a circle
·                                 Hybrid topology – combine network layout types to meet their wants.
(5) What is network /communication protocols?
Answer :- A protocol is s an agreed/admitted set of rules and procedures for exchanging data between two or more devices.
Features :
·                                 The sending device shows it has finished sending the message.
·                                 The receiving device shows it has received the message.
The type of error checking to be used.
Ethernet is used by most networks, but some network may use  Token Ring protocol from IBM.
(6) What are the communication types?
Answer: There are three types of communication.
·                                 Unicasting –Here one to one communication occurs
·                                 Multicasting –Here one to many communication occurs
·                                 Broadcasting –here one to all communication occurs.
(7) What is client/server network?
Answer:
·                                  Here nodes and servers share data roles.
·                                  Nodes are defined as clients.
·                                  To control access servers are used.
·                                  Server is the most important part computer.
 (8) What is STAR connectivity in computer network?
Answer: Here all nodes are connect to a hub. Packets sent to hub. Again packets are sent by Hub to destination.
Advantages
·                                 It is easy to set up in a network.
·                                 One single cable can not crash the whole network.
             Disadvantages
·                                 One single hub crashing downs the whole network
·                                  It uses a lot of cables
·                                 It is the most common topology
(9) What is RING connectivity in computer network?
Answer: Here all nodes are  connected in a circle. Token is used for transferring data from computers. Here nodes  waits for token to send.
Advantages
·                                 Time for sending data is known.
·                                  Here no data collisions occurs
Disadvantages
·                                  Connection is very slow
·                                 Lots of cable required.
(10) Define HUB, SWITCH, ROUTER
Answer: These are the larger one connections of networks. multiple segments are connected to them
·                                 Hub:- It is a multiport repeater to enhance signals within the same LAN
·                                 Switch:- It is mostly like hub but it is more intelligent.It gives better performance
·                                 Router:- It forwards packets from one LAN to another LAN.

11) What is a Link?
A link refers to the connectivity between two devices. It includes the type of cables and protocols used in order for one device to be able to communicate with the other.
12) What are the layers of the OSI reference model?
There are 7 OSI layers: Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer and Application Layer.
13) What is backbone network?
A backbone network is a centralized infrastructure that is designed to distribute different routes and data to various networks. It also handles management of bandwidth and various channels.
14) What is a LAN?
LAN is short for Local Area Network. It refers to the connection between computers and other network devices that are located within a small physical location.
15) What is a node?

A node refers to a point or joint where a connection takes place. It can be computer or device that is part of a network. Two or more nodes are needed in order to form a network connection.
16) What are routers?
Routers can connect two or more network segments. These are intelligent network devices that store information in its routing table such as paths, hops and bottlenecks. With this info, they are able to determine the best path for data transfer. Routers operate at the OSI Network Layer.
17) What is point to point link?
It refers to a direct connection between two computers on a network. A point to point connection does not need any other network devices other than connecting a cable to the NIC cards of both computers.
18) What is anonymous FTP?
Anonymous FTP is a way of granting user access to files in public servers. Users that are allowed access to data in these servers do not need to identify themselves, but instead log in as an anonymous guest.
19) What is subnet mask?
A subnet mask is combined with an IP address in order to identify two parts: the extended network address and the host address. Like an IP address, a subnet mask is made up of 32 bits.
20) Describe Network Topology
Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.
21) What is VPN?
VPN means Virtual Private Network, a technology that allows a secure tunnel to be created across a network such as the Internet. For example, VPNs allow you to establish a secure dial-up connection to a remote server.
22) What is the job of the Network Layer under the OSI reference model?
The Network layer is responsible for data routing, packet switching and control of network congestion. Routers operate under this layer.
23) What are different ways of securing a computer network?
There are several ways to do this. Install reliable and updated anti-virus program on all computers. Make sure firewalls are setup and configured properly. User authentication will also help a lot. All of these combined would make a highly secured network.
24) What is NIC?
NIC is short for Network Interface Card. This is a peripheral card that is attached to a PC in order to connect to a network. Every NIC has its own MAC address that identifies the PC on the network.
25) What is WAN?
WAN stands for Wide Area Network. It is an interconnection of computers and devices that are geographically dispersed. It connects networks that are located in different regions and countries.
26) What is the importance of the OSI Physical Layer?
The physical layer does the conversion from data bits to electrical signal, and vice versa. This is where network devices and cable types are considered and setup.
27) How many layers are there under TCP/IP?
There are four layers: the Network Layer, Internet Layer, Transport Layer and Application Layer.
28) What are proxy servers and how do they protect computer networks?
Proxy servers primarily prevent external users who identifying the IP addresses of an internal network. Without knowledge of the correct IP address, even the physical location of the network cannot be identified. Proxy servers can make a network virtually invisible to external users.
29) What is the function of the OSI Session Layer?
This layer provides the protocols and means for two devices on the network to communicate with each other by holding a session.  This includes setting up the session, managing information exchange during the session, and tear-down process upon termination of the session.
30) What is OSI and what role does it play in computer networks?
OSI (Open Systems Interconnect) serves as a reference model for data communication. It is made up of 7 layers, with each layer defining a particular aspect on how network devices connect and communicate with one another. One layer may deal with the physical media used, while another layer dictates how data is actually transmitted across the network.
31) What is the equivalent layer or layers of the TCP/IP Application layer in terms of OSI reference model?
The TCP/IP Application layer actually has three counterparts on the OSI model: the Session layer, Presentation Layer and Application Layer.
32) How can you identify the IP class of a given IP address?
By looking at the first octet of any given IP address, you can identify whether it’s Class A, B or C. If the first octet begins with a 0 bit, that address is Class A. If it begins with bits 10 then that address is a Class B address. If it begins with 110, then it’s a Class C network.
33) What is the main purpose of OSPF?
OSPF, or Open Shortest Path First, is a link-state routing protocol that uses routing tables to determine the best possible path for data exchange.
34) What are firewalls?
Firewalls serve to protect an internal network from external attacks. These external threats can be hackers who want to steal data or computer viruses that can wipe out data in an instant. It also prevents other users from external networks from gaining access to the private network.
35) Describe star topology
Star topology consists of a central hub that connects to nodes. This is one of the easiest to setup and maintain.
36) What are gateways?
Gateways provide connectivity between two or more network segments. It is usually a computer that runs the gateway software and provides translation services. This translation is a key in allowing different systems to communicate on the network.
37) What is the disadvantage of a star topology?
One major disadvantage of star topology is that once the central hub or switch get damaged, the entire network becomes unusable.
38) What is SLIP?
SLIP, or Serial Line Interface Protocol, is actually an old protocol developed during the early UNIX days. This is one of the protocols that are used for remote access.
39) Give some examples of private network addresses.
10.0.0.0 with a subnet mask of 255.0.0.0
172.16.0.0 with subnet mask of 255.240.0.0
192.168.0.0 with subnet mask of 255.255.0.0
40) What are the functions of a network administrator?
A network administrator has many responsibilities that can be summarize into 3 key functions: installation of a network, configuration of network settings, and maintenance/troubleshooting of networks.
41) Describe at one disadvantage of a peer to peer network.
When you are accessing the resources that are shared by one of the workstations on the network, that workstation takes a performance hit.
42) What is DHCP?
DHCP is short for Dynamic Host Configuration Protocol. Its main task is to automatically assign an IP address to devices across the network. It first checks for the next available address not yet taken by any device, then assigns this to a network device.
43) What is the main job of the ARP?
The main task of ARP or Address Resolution Protocol is to map a known IP address to a MAC layer address.
44) What is TCP/IP?
TCP/IP is short for Transmission Control Protocol / Internet Protocol. This is a set of protocol layers that is designed to make data exchange possible on different types of computer networks, also known as heterogeneous network.
45) How can you manage a network using a router?
Routers have built in console that lets you configure different settings, like security and data logging. You can assign restrictions to computers, such as what resources it is allowed access, or what particular time of the day they can browse the internet. You can even put restrictions on what websites are not viewable across the entire network.
46) What is the use of a default gateway?
Default gateways provide means for the local networks to connect to the external network. The default gateway for connecting to the external network is usually the address of the external router port.
47) What is peer to peer?
Peer to peer are networks that does not reply on a server. All PCs on this network act as individual workstations.
48) What is DNS?
DNS is Domain Name System. The main function of this network service is to provide host names to TCP/IP address resolution.
49) What advantages does fiber optics have over other media?
One major advantage of fiber optics is that is it less susceptible to electrical interference. It also supports higher bandwidth, meaning more data can be transmitted and received. Signal degrading is also very minimal over long distances.
50) What is the difference between a hub and a switch?
A hub acts as a multiport repeater. However, as more and more devices connect to it, it would not be able to efficiently manage the volume of traffic that passes through it. A switch provides a better alternative that can improve the performance especially when high traffic volume is expected across all ports.
51) What are the maximum networks and hosts in a class A, B and C network?
For Class A, there are 126 possible networks and 16,777,214 hosts
For Class B, there are 16,384 possible networks and 65,534 hosts
For Class C, there are 2,097,152 possible networks and 254 hosts
52) What is client/server?
Client/server is a type of network wherein one or more computers act as servers. Servers provide a centralized repository of resources such as printers and files. Clients refers to workstation that access the server.
53) Describe networking.
Networking refers to the inter connection between computers and peripherals for data communication. Networking can be done using wired cabling or through wireless link.
54) In a network that contains two servers and twenty workstations, where is the best place to install an Anti-virus program?
An anti-virus program must be installed on all servers and workstations to ensure protection. That’s because individual users can access any workstation and introduce a computer virus when plugging in their removable hard drives or flash drives.
55) Describe Ethernet.
Ethernet is one of the popular networking technologies used these days. It was developed during the early 1970s and is based on specifications as stated in the IEEE. Ethernet is used in local area networks.
56) What are some drawbacks of implementing a ring topology?
In case one workstation on the network suffers a malfunction, it can bring down the entire network. Another drawback is that when there are adjustments and reconfigurations needed to be performed on a particular part of the network, the entire network has to be temporarily brought down as well.
57) What is the difference between CSMA/CD and CSMA/CA?
CSMA/CD, or Collision Detect, retransmits data frames whenever a collision occurred. CSMA/CA, or Collision Avoidance, will first broadcast intent to send prior to data transmission.
58) What is SMTP?
SMTP is short for Simple Mail Transfer Protocol. This protocol deals with all Internal mail, and provides the necessary mail delivery services on the TCP/IP protocol stack.
59) What is multicast routing?
Multicast routing is a targeted form of broadcasting that sends message to a selected group of user, instead of sending it to all users on a subnet.
60) What is the importance of Encryption on a network?
Encryption is the process of translating information into a code that is unreadable by the user. It is then translated back or decrypted back to its normal readable format using a secret key or password. Encryption help ensure that information that is intercepted halfway would remain unreadable because the user has to have the correct password or key for it.
61) What is one advantage of mesh topology?
In the event that one link fails, there will always be another available. Mesh topology is actually one of the most fault-tolerant network topology.
62) What protocols fall under the TCP/IP Internet Layer?
There are 4 protocols that are being managed by this layer. These are ICMP, IGMP, IP and ARP.
63) When it comes to networking, what are rights?
Rights refer to the authorized permission to perform specific actions on the network. Each user on the network can be assigned individual rights, depending on what must be allowed for that user.
64) What is one basic requirement for establishing VLANs?
A VLAN is required because at switch level there is only one broadcast domain, it means whenever new user is connected to switch this information is spread throughout the network. VLAN on switch helps to create separate broadcast domain at  switch level. It is used for security purpose.
65) What is IPv6?
IPv6 , or Internet Protocol version 6, was developed to replace IPv4. At present, IPv4 is being used to control internet traffic, butis expected to get saturated in the near future. IPv6 was designed to overcome this limitation.
66) What is mesh topology?
Mesh topology is a setup wherein each device is connected directly to every other device on the network. Consequently, it requires that each device have at least two network connections.
67) what is the maximum segment length of a 100Base-FX network?
The maximum allowable length for a network segment using 100Base-FX is 412 meters. The maximum length for the entire network is 5 kilometers.

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