SBI IT OFFICER THEORY MCQ-6

1)DTE is the end user management machine, generally refers to terminals and computers eg: email terminal, workstation, ATM, sales terminal in a department store.DCE is used to connect the communication channel. Modem is DCE device. It interacts with DTE and provides an interface of DTE to communication network transmit and receives bit one at a time over the communication channel. Modem, Switch,hub,Repeaters etc all are DCE devices.DCE devices provide the clock signal (internal clocking) and the DTE device synchronizes on the provided clock (external clocking). 

2)A microcontroller (or MCU, short for microcontroller unit) is a small computer(SoC) on a single integrated circuit containing a processor core,memory,and programmable  input/output peripherals. Communication Handler(or COMH) is basically an 80C186 16 bit micro controller based card working at a clock speed of 6Mhz.

3) Class A: 1.0.0.1 to 126.255.255.254   Supports 16 million hosts on each of 127 networks.   Class B: 128.1.0.1 to 191.255.255.254   Supports 65,000 hosts on each of 16,000 networks.   Class C: 192.0.1.1 to 223.255.254.254   Supports 254 hosts on each of 2 million networks.   Class D: 224.0.0.0 to 239.255.255.255   Reserved for multicast groups.   Class E: 240.0.0.0 to 254.255.255.254   Reserved for future use, or Research and Development Purposes.

4) A gateway is a network node connecting two networks that use different protocols.Gateways can take several forms -- including routers or computers -- and can perform a variety of tasks. These range from simply passing traffic on to the next hop on its path to offering complex traffic filtering, proxies or protocol translations at various network layers.

The most common gateway is the internet gateway, which connects a home or enterprise network to the internet. An internet gateway also often acts as a security node, variously filling one or more security roles, such as proxy server, firewall or network address translation (NAT) server. Software-defined WAN (SD-WAN) and virtual WAN systems serve as gateways between an enterprise network and two or more wide area networks (WANs).

5)White-box testing (also known as clear box testing, glass box testing, transparent box testing, and structural testing) is a method of testing software that tests internal structures or workings of an application, as opposed to its functionality (i.e. black-box testing). In white-box testing an internal perspective of the system, as well as programming skills, are used to design test cases.White-box testing can be applied at the unit, integration and system levels of the software testing process.

6)IPSec is a suite of protocols that provide security services at IP layer of TCP/IP stack i.e. Network Layer in OSI model.

As Andy Lemke mentioned, IPSec suite comprises of two protocols to offer security to
1. AH - Authentication Header Protocol.(Protocol no: 51)
2. ESP - Encapsulation of security payload Protocol. (Protocol no:50)
AH provides authentication, integrity and anti-replay services at Network Layer and above.
ESP provides authentication, integrity, anti-replay and confidentiality services at Transport Layer and above.
Hence, we can say, IPSec(AH+ESP) operates at Network Layer and provide security services at Network and above layers.

7)A wildcard character can be used to substitute for any other character(s) in a string.In SQL, wildcard characters are used with the SQL LIKE operator.SQL wildcards are used to search for data within a table. 

8)A loopback address is a type of IP address that is used to test the communication or transportation medium on a local network card and/or for testing network applications. Data packets sent on a loopback address are re-routed back to the orginating node without any alteration or modification.In IPv4, 127.0.0.1 is the most commonly used loopback address, however, this can range be extended to 127.255.255.255.

9)Data warehousing is the process of constructing and using a data warehouse. A data warehouse is constructed by integrating data from multiple heterogeneous sources that support analytical reporting, structured and/or ad hoc queries, and decision making. Data warehousing involves data cleaning, data integration, and data consolidations.

To integrate heterogeneous databases, we have two approaches:

•Query-driven Approach

•Update-driven Approach

10)Queue is also an abstract data type or a linear data structure, in which the first element is inserted from one end called REAR(also called tail), and the deletion of exisiting element takes place from the other end called as FRONT(also called head). This makes queue as FIFO data structure, which means that element inserted first will also be removed first.

The process to add an element into queue is called Enqueue and the process of removal of an element from queue is called Dequeue.

peek( ) function is oftenly used to return the value of first element without dequeuing it.