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Difference between LINQ to SQL and Entity Framework


LINQ to SQL allow you to query and modify SQL Server database by using LINQ syntax. Entity framework is a great ORM shipped by Microsoft which allow you to query and modify RDBMS like SQL Server, Oracle, DB2 and MySQL etc. by using LINQ syntax. Today, EF is widely used by each and every .NET application to query to database. The difference between LINQ to SQL and EF is given below.

LINQ to SQL
Entity Framework
It only works with SQL Server Database.
It can works with various databases like Oracle, DB2, MYSQL, SQL Server etc.
It generates a .dbml to maintain the relation
It generates an .edmx files initially. The relation is maintained using 3 different files .csdl, .msl and .ssdl
It has not support for complex type.
It has support for complex type.
It cannot generate database from model.
It can generate database from model.
It allows only one to one mapping between the entity classes and the relational tables /views.
It allows one-to-one, one-to-many & many-to-many mappings between the Entity classes and the relational tables /views
It allows you to query data using DataContext.
It allows you to query data using EntitySQL, ObjectContext, DbContext.
It provides a tightly coupled approach.
It provides a loosely coupled approach. Since its code first approach allow you to use Dependency Injection pattern which make it loosely coupled .
It can be used for rapid application development only with SQL Server.
It can be used for rapid application development with RDBMS like SQL Server, Oracle, DB2 and MySQL etc.

Oracle 12C New Features

 The Oracle 12C means different things to different people. It all depends on which areas you are looking at, as there are improvements in many areas. Summarized below is the list of Top 12 Features of Oracle 12C as I see it. I have summarized below, the top 12 which I found interesting.


01. Pluggable Databases Through Database Consolidation:

Oracle is doing every thing to jump into the cloud bandwagon. With 12C, Oracle is trying to address the problem of Multitenancy through this feature. There is a radical change and a major change in the core database architecture through the introduction of Container Databases also called CBD and Pluggable Databases (PDB). The memory and process is owned by the Container Database. The container holds the metadata where the PDBs hold the user data. You can create upto 253 PDBs including the seed PDB.
In a large setup, it is common to see 20 or 30 different instances running in production environment. With these many instances, it is a maintenance nightmare as all these instances have to be separately
•Upgraded
•Patched
•Monitored
•Tuned
•RAC Enabled
•Adjusted
•Backed up and 
•Data Guarded.

With Pluggable Databases feature, you just have to do all this for ONE single instance. Without this feature, prior to 12C, you would have to create separate schemas and there is always a thread of security how much ever the isolation we build into it. There are problems with namespace conflicts, there is always going to be one public synonym that you can create. With PDBs you can have a separate HR or Scott schema for each PDB, separate Emp, Dept Tables and separate public synonyms. Additionally, 2 PDBs can talk to each other through the regular DB Link feature. There is no high startup cost of creating a database any more. Instead of one instance per day, the shift is into one instance per many databases. For the developer community, you can be oblivious of all this and still continue to use the PDBs as if it were a traditional database, but for the DBAs the world would look like it has changed a lot.
Another cool feature is, you can allocate a CPU percentage for each PDB.
Another initiative being, it has announced a strategic tieup with salesforce.com during the first week of July 2013.

02. Redaction Policy:

This is one of the top features in Oracle 12C. Data Redaction in simple terms means, masking of data. You can setup a Data Redaction policy, for example SSN field in a Employee table can be masked. This is called redaction. From Sql Develop you can do this by going to the table: Employee->Right click on Security Policy->click on New->click on Redaction Policy->Enter SSN. 
When you do a select * from employee, it will show that the SSN is masked.
The new data masking will use a package called DBMS_REDACT. It is the extension to the FGAC and VPD present in earlier versions.
By doing this, whoever needs to view the data will be able to see it where as the other users will not be able to view it.

03. Top N Query and Fetch and offset Replacement to Rownum:

With the release of Oracle Database 12c, Oracle has introduced this new SQL syntax to simplify fetching the first few rows. The new sql syntax "Fetch First X Rows only" can be used.

04. Adaptive Query Optimization and Online Stats Gathering:

With this feature, it helps the optimizer to make runtime adjustments to execution plan which leads to better stats. For statements like CTAS (Create Table As Select) and IAS (Insert As Select), the stats is gathered online so that it is available immediately.

05. Restore a Table easily through RMAN:

Earlier if you had to restore a particular table, you had to do all sorts of things like restoring a tablespace and or do Export and Import. The new restore command in RMAN simplifies this task.

06. Size Limit on Varchar2, NVarchar2, Raw Data Types increased:

The previous limit on these data types was 4K. In 12C, it has been increased to 32,767 bytes. Upto 4K, the data is stored inline. I am sure everyone will be happy with this small and cute enhancement.

07. Inline PL/SQL Functions and Procedures:

The in line feature is extended in Oracle 12C. In addition to Views, we can now have PL/SQL Procedures and Functions as in line constructs. The query can be written as if it is calling a real stored procedure, but however the functions do not actually exist in the database. You will not be able to find them in ALL_OBJECTS. I think this will be a very good feature for the developers to explore as there is no code that needs to be compiled.

08. Generated as Identity/Sequence Replacement:

You can now create a col with 'generated as identity' clause. Thats it. Doing this is equivalent to creating a separate sequence and doing a sequence.nextval for each row. This is another handy and a neat feature which will help developer community. This is also called No Sequence Auto Increment Primary Key.

09. Multiple Indexes on a Single Column:

Prior to 12C, a column cant be in more than one index. In 12C, you can include a column in B-tree index as well as a Bit Map index. But, please note that only one index is usable at a given time.

10. Online Migration of Table Partition or Sub Partition:

You can very easily migrate a partition or sub partition from one tablespace to another. Similar to how the online migration was achieved for a non-partitioned table in prior releases, a table partition or sub partition can be moved to another tablespace online or offline. When an ONLINE clause is specified, all DML operations can be performed without any interruption on the partition|sub-partition which is involved in the procedure. In contrast, no DML operations are allowed if the partition|sub-partition is moved offline.

11. Temporary UNDO:

Prior to 12C, undo records generated by TEMP Tablespace is stored in the undo tablespace. With Temp undo feature in 12C, temp undo records can be stored in temporary table instead of UNDO TS. The benefit is - reduced undo tablespace and reduced redo log space used.
SQL> ALTER SYSTEM SET PGA_AGGREGATE_LIMIT=2G;
SQL> ALTER SYSTEM SET PGA_AGGREGATE_LIMIT=0; --disables the hard limit

12. In Database Archiving:

This feature enables archiving rows within a table by marking them as inactive. These inactive rows are in the database and can be optimized using compression but are not visible to the application. These records are skipped during FTS (Full Table Scan).

Other Features:

Advanced Replication and Streams are Dead. It is being replaced with Oracle Golden Gate.
Invisible Columns. You can now have a invisible column in a table. When a column is defined as invisible, the column won’t appear in generic queries
PGA Aggregate Limit setting:
In 12c, you can set a hard limit on PGA by enabling the automatic PGA management, which requires PGA_AGGREGATE_LIMIT parameter settings. Therefore, you can now set the hard limit on PGA by setting the new parameter to avoid excessive PGA usage.
DDL Logging:
The DDL statements will automatically get recorded in xml/log file if ENABLE_DDL_LOGGING is set to True. ALTER SYSTEM|SESSION SET ENABLE_DDL_LOGGING=TRUE



An Introduction to Entity Framework for Beginners


Introduction

This article introduces Entity Framework to absolute beginners. The article is meant for developers who are primarily using ADO.NET to write their data access layers. Many experienced developers will find this article very basic but since the article is written from the perspective of beginners, I've tried to keep things simple.

Background

ADO.NET is a very strong framework for data access. ADO.NET has been around since many years and there are a lot of systems running over ADO.NET. Developers who are totally oblivious to the concept of ORMs will probably be asking "What is Entity Framework? What are the benefits of using it and is it an alternative to ADO.NET?"
Well, to answer the first question about what is Entity Framework, Entity Framework is an Object Relational Mapper (ORM). It basically generates business objects and entities according to the database tables and provides the mechanism for:
  1. Performing basic CRUD (Create, Read, Update, Delete) operations.
  1. Easily managing "1 to 1", "1 to many", and "many to many" relationships.
  1. Ability to have inheritance relationships between entities.
and to answer the second question, the benefits are:
  1. We can have all data access logic written in higher level languages.
  1. The conceptual model can be represented in a better way by using relationships among entities.
  1. The underlying data store can be replaced without much overhead since all data access logic is present at a higher level.
and finally, the last question that whether it is an alternative to ADO.NET, the answer would be "yes and no". Yes because the developer will not be writing ADO.NET methods and classes for performing data operations and no because this model is actually written on top of ADO.NET, meaning under this framework, we are still using ADO.NET. So let us look at the architecture of Entity Framework (diagram taken from MSDN):
Entity framework article image

Using the code

Let's try to understand the ease of use that Entity Framework provides by performing simple CRUD operations. Once we look at the code and how effortlessly and efficiently we can do these operations, the benefits of Entity Framework will become quite obvious.
Creating the database
Let's have a simple database with one table. Let's create a simple table for Contacts and we will perform CRUD operations on this table.
Entity framework article image
Adding the Entity Model to the Website
Once we have the database ready, we can add the entity model to our website. We can do this by adding anADO.NET Entity Data Model to the website.
Entity framework article image
Once we select to add this data model to our website, we will have to select the approach we want to take for our Model's contents.
Entity framework article image
What this selection means is that we can either choose to generate the entity model from an existing database schema or we can design the entity model here and then later hook it up to the database. Since we already have the database ready, we will use the first option. Once the Model is generated, the Entity for each table is generated. The generated entity for our contact table is:
Entity framework article image
Also, the classes for performing database operations are also created. We just need to know how to use these classes to perform database operations.
Entity framework article image
Insert operation
Let us create a simple page to perform an insert operation.
Entity framework article image
Now once the user chooses to insert the values into the database, the actual data operation can be performed by using the AddObject method of the Model class entity collection. The following code snippet show how to perform the insert.

Contact con = new Contact();
con.fname = TextBox1.Text;
con.lname = TextBox2.Text;
con.phone = TextBox3.Text;
ContactsDb db = new ContactsDb();
db.Contacts.AddObject(con);
db.SaveChanges();
This will insert the record into the table. You can notice the simplicity and efficiency of the code we wrote to perform the insertion.
Reading all the records
There are scenarios when we want to read all records. Let's say we are making a page that will display all the contact information in a single page.
Entity framework article image
We can retrieve the collection of Entities using the Model object to achieve this. The code snippet below will show how that can be done.

ContactsDb db = new ContactsDb();
Repeater1.DataSource = db.Contacts;
Repeater1.DataBind();
Selecting a specific record
If we want to select a specific record from the table, we can use the SingleOrDefault method on the Model's entities collection. Let's say we want the functionality of updating/deleting a record on a single page then we will first have to select the record based on the ID, then update/delete the selected record.
Entity framework article image
Selection of any particular record (Contact) based on ID can be done as:

int idToupdate = Convert.ToInt32(Request.QueryString["id"].ToString());
ContactsDb db = new ContactsDb();
Contact con = db.Contacts.SingleOrDefault(p => p.id == idToupdate);
Once this code is executed, the Contact object will contain the required values.
Updating the record
If we want to update a record, then a simple update operation can be performed as:

int idToupdate = Convert.ToInt32(Request.QueryString["id"].ToString());
ContactsDb db = new ContactsDb();
Contact con = db.Contacts.SingleOrDefault(p => p.id == idToupdate); con.phone = TextBox1.Text;
db.SaveChanges();
Once this code executes, the value of phone number will be updated by a new value which is retrieved fromTextBox1.
Deleting a record
If we want to delete a particular record then we can perform a delete operation by using the DeleteObjectfunction. The following code snippet demonstrates the same:

//delete this contact
int idToupdate = Convert.ToInt32(Request.QueryString["id"].ToString());
ContactsDb db = new ContactsDb();
Contact con = db.Contacts.SingleOrDefault(p => p.id == idToupdate); 

db.Contacts.DeleteObject(con);
db.SaveChanges();


Now that we have the basic CRUD operations performed on the database using the Entity Framework.
A note on Relationships and Lazy Loading
To understand the Entity Framework we need to understand some things like naming conventions, relationships between tables, and relationships between entities. Also, the concept of lazy loading once fully understood will give the power to the developer to use the Entity Framework efficiently.
Note: Since this is an introductory article on Entity Framework we have not discussed these things. Perhaps we will discuss them in a separate article.
Entity Framework has been in use for some time now. But there are many developers who are still getting started with Entity Framework. This article was meant as an overview of the Entity Framework. This should not be treated as a complete tutorial. Also, the code written is very simple and there is a lot of scope for optimization but since the idea here is to understand Entity Framework, I tried to keep the code simple and readable rather and optimal.

Installing Oracle Database and Creating a Database(Linux) OS


  1. Log on to your computer as a member of the administrative group that is authorized to install Oracle Database software and to create and run the database.
    Refer to your operating system-specific documentation or contact your system administrator to determine whether you have the necessary privileges and permissions to install new software.
  2. Do one of the following:
    • If you are installing from distribution media, then insert the distribution media for the database into your computer.
      The Autorun feature opens the Select a Product to Install window automatically.
    • If you downloaded the installation software from the Oracle Web site, then follow the instructions on the site to run the Oracle Universal Installer. Or, see the Oracle Database Installation Guide for your platform.
  3. The first window that appears is the Configure Security Updates window. To receive notifications about security issues via e-mail, enter your e-mail address in the Email text field. To receive security updates from My Oracle Support, enter the e-mail address registered with My Oracle Support, select the I wish to receive security updates... option, and enter your My Oracle Support password.
    Click Next to continue.
    The Select Installation Option window appears.
  4. Choose the Create and configure a database option. Or, you also have the option of choosing to only install the database software, but then you must create a database in an additional step after the software is installed. If you are currently using a previous version of Oracle Database, choose Upgrade an existing database. After you have chosen an option, click Next.
    The System Class window appears.
  5. Choose Desktop Class.
    You can choose the Server Class option to customize your installation. For example, you use this method to configure Oracle Automatic Storage Management for your database, install the Sample Schemas, or configure automated backups. Selecting this option guides you through a series of installation steps that are not documented in this guide. For more information about the advanced choices, see "About Advanced Installation". Also see Oracle Database Installation Guide for your platform.
    Click Next.
    The Typical Install Configuration window appears.
    Description of install_basic.gif follows

  6. Provide the following configuration details for the database:
    • Oracle Base Location— The Oracle base directory helps to facilitate the organization of multiple Oracle software installations. See the Oracle Database Installation Guide for your platform for more information about ORACLE_BASE.
      If you did not set the ORACLE_BASE environment variable before starting OUI, then the Oracle base directory is created in anapp/username/directory on the first existing and writable directory from /u01 through /u09 for UNIX and Linux systems, or on the disk drive with the most available space for Windows systems. If /u01 through /u09 does not exist on the UNIX or Linux system, then the default location is user_home_directory/app/username.
      You can click Browse to find the directory you want to act as the Oracle base directory.
    • Software Location—The software location is the Oracle home for your database. You must specify a new Oracle home directory for each new installation of Oracle Database software. By default, the Oracle home directory is a subdirectory of the Oracle base directory.
      You can click Browse to find the directory where you want to install the Oracle Database software.
    • Database File Location—The database file location is the location where Oracle Database files are stored. By default, this location is Oracle_base/oradata. You can click Browse to select a different location.
    • Database Edition—Select either Enterprise EditionStandard EditionStandard Edition One, or Personal Edition (Microsoft Windows platforms only). See "Installation Type".
    • Character Set—Choose the character set to use to store the data within the database. You can choose between the Default, which is based on the operating system language settings, or Unicode.
    • OSDBA Group (Linux and UNIX platforms only)—Specify the operating system DBA group. Host computer users in this group have administrative privileges on the database. This group is typically named dba. Refer to Oracle Database Installation Guide for Linuxor for your UNIX platform for more details.
    • Global Database Name—Enter the fully qualified global database name. See "Installation Type" for more on global database name.
    • Administrative Password—Specify the initial password for the SYSSYSTEMSYSMAN, and DBSNMP administrator accounts. If the password you choose is not a secure password, a warning message will be displayed.
    After you enter the required information, click Next.
    If Oracle software has not previously been installed on this server, then the Create Inventory window appears. If this is not the first installation attempt on this server, then the Perform Prerequisite Checks window appears.
  7. For first time installations on Linux and UNIX operating systems only, specify a directory for installation files and the name of an operating system group that has write permissions for that directory.
    If this is the first time you are installing any Oracle software on this computer, then the Create Inventory Directory window appears. You must specify a local directory for the inventory, which OUI uses to keep track of all Oracle software installed on the computer. This information is used while applying patches or upgrading an existing installation, and while deinstalling Oracle software. Note that this directory is different from the Oracle home directory. The recommended value for the inventory directory isOracle_base/../oraInventory, or one level above the Oracle base directory, in the oraInventory subdirectory. If your Oracle base directory is /u01/app/oracle, then the Oracle inventory directory defaults to /u01/app/oraInventory.
    In this window you can also specify the operating system group that has write permissions on the inventory directory. This prevents other users from writing over the Oracle product installation files. Typically the oinstall group is selected.
    After you enter a directory path and optionally specify an operating system group, click Next to continue.
    The Perform Prerequisite Checks window appears.
  8. If any checks failed, then take corrective actions.
    OUI performs several environment checks and indicates whether the check was a success, or resulted in a warning or failure. Details of the checks are provided in the displayed window. The installation can proceed only when all checks have a status of either Succeeded or Warning. If any of the environment checks failed, then they must be resolved manually. See "Checking Prerequisites" for more information.
    If all the prerequisite checks passed, or after you click Next, the Summary window appears,
  9. Review the installation summary, then click Finish to start the installation.
    The Install window appears, showing the installation progress. After the installation phase, the Configuration Assistants window appears. This window lists the configuration assistants that are started automatically. If you chose to create a starter database, then Database Configuration Assistant starts automatically in a separate window.
    After database creation, a window is displayed that summarizes the database creation.
  10. (Optional) Click Password Management to unlock user accounts to make the accounts accessible to users.
    The SYS and SYSTEM accounts are unlocked by default.
  11. Click OK to continue the installation.
  12. For Linux and UNIX operating systems only, run the specified scripts, then click OK.
    In the Execute Configuration Scripts window, you are prompted to open a new terminal window, and to run scripts as the root user. After you run the scripts, return to this window and click OK.
  13. Make note of the information in the Finish window, then click Close to exit OUI.
    Your installation and database creation is now complete. The Finish window displays one or more important URLs, including one for the Oracle Enterprise Manager Database Control console. (The console is the user interface—the Web application—portion of Oracle Enterprise Manager Database Control.)
    You use Oracle Enterprise Manager Database Control to perform common database administration tasks. The URL and port information for Database Control can be found after installation in the Oracle_home/install/portlist.ini file.



Top 30 CCNA Interview Questions


 

1)    What is Routing?


Routing is the process of finding a path on which data can pass from source to destination. Routing is done by a device called routers, which are network layer devices.


2)    What is the purpose of the Data Link?


The job of the Data Link layer is to check messages are sent to the right device. Another function of this layer is framing.

3)    What is the key advantage of using switches?


When a switch receives a signal, it creates a frame out of the bits that was extracted from that signal. With this process, it gains access and reads the destination address, after which it forwards that frame to the appropriate port. This is a very efficient means of data transmission, instead of broadcasting it on all ports.

4)    When does network congestion occur?


Network congestion occurs when too many users are trying to use the same bandwidth. This is especially true in big networks that do not resort to network segmentation.

5)    What is a Window in networking terms?


A Window refers to the number of segments that is allowed to be sent from source to destination before an acknowledgement is sent back.

6)    Does a bridge divide a network into smaller segments?


Not really. What a bridge actually does is to take the large network and filter it, without changing the size of the network.

7)    Which LAN switching method is used in CISCO Catalyst 5000?



This model uses the Store-and-forward switching method. It stores the entire frame to its buffers and performs a crc check before deciding whether or not to forward that data frame.

8 ) What is the role of the LLC sublayer?


The LLC sublayer, short for Logical Link Control, can provide optional services to an application developer. One option is to provide flow control to the Network layer by using stop/start codes. The LLC can also provide error correction.

9)    How does RIP differ from IGRP?


RIP relies on the number of hops in order to determine the best route to a network. On the other hand, IGRP takes consideration many factors before it decides the best route to take, such as bandwidth, reliability, MTU and hop count.

10)    What are the different memories used in a CISCO router?


-    NVRAM stores the startup configuration file
-    DRAM stores the configuration file that is being executed
-    Flash Memory - stores the Cisco IOS.

11)    What is BootP?


BootP is a protocol that is used to boot diskless workstations that are connected to the network. It is short for Boot Program. Diskless workstations also use BootP in order to determine its own IP address as well as the IP address of the server PC.

12)    What is the function of the Application Layer in networking?


The Application Layer supports the communication components of an application and provides network services to application processes that span beyond the OSI reference model specifications. It also synchonizes applications on the server and client.

13)    Differentiate User Mode from Privileged Mode


User Mode is used for regular task when using a CISCO router, such as to view system information, connecting to remote devices, and checking the status of the router. On the other hand, privileged mode includes all options that are available for User Mode, plus more. You can use this mode in order to make configurations on the router, including making tests and debugging.

14)    What is 100BaseFX?


This is Ethernet that makes use of fiber optic cable as the main transmission medium. The 100 stands for 100Mbps, which is the data speed.


15)    Differentiate full-duplex from half-duplex.


In full-duplex, both the transmitting device and the receiving device can communicate simultaneously, that is, both can be transmitting and receiving at the same time. In the case of half-duplex, a device cannot receive while it is transmitting, and vice versa.

16)    What is MTU?


MTU stands for Maximum Transmission Unit. It refers to the maximum packet size that can be sent out onto the data line without the need to fragment it.

17)    How does cut-through LAN switching work?


In Cut-Through LAN switching, as soon as the router receives the data frame, it will immediately send it out again and forward it to the next network segment after reading the destination address.

18)    What is latency?


Latency is the amount of time delay that measures the point from which a network device receives a data frame to the time it sends it out again towards another network segment.

19)    Utilizing RIP, what is the limit when it comes to number of hops?


The maximum limit is 15 hop counts. Anything higher than 15 indicates that the network is considered unreachable.

20)    What is a Frame Relay?


Frame Relay is a WAN protocol that provides connection-oriented communication by creating and maintaining virtual circuits. It has a high performance rating and operates at the Data Link and Physical Layers.

21)    How do you configure a Cisco router to route IPX?


The initial thing to do is to enable IPX routing by using the "ipx routing" command. Each interface that is used in the IPX network is then configured with a network number and encapsulation method.

22)    What are the different IPX access lists?


There are two access lists: Standard and Extended. Standard Access List can only filter the source or destination IP address. An Extended Access List uses the source and destination IP addresses, port, socket and protocol when filtering a network.

23)    Explain the benefits of VLANs.



VLANs allow the creation of collision domains by groups other than just physical location. Using VLANs, it is possible to establish networks by different means, such as by function, type of hardware, protocol, among others. This is a big advantage when compared to conventional LANs wherein collision domains are always tied to physical location.

24)    What is subnetting?


Subnetting is the process of creating smaller networks from a big parent network. Being a part of a network, each subnet is assigned some additional parameters or identifier to indicate its subnet number.

25)    What are the advantages of a layered model in the networking industry?


A layered network offers many advantages. It allows administrators to make changes in one layer without the need to make changes in the other layers. Specialization is encouraged, allowing the network industry to make progress faster. A layered model also lets administrators troubleshoot problems more efficiently.

26)    Why is UDP lease favored when compared to TCP?


It's because UDP is unreliable and unsequenced. It is not capable of establishing virtual circuits and acknowledgements.

27)    What are some standards supported by the Presentation layer?


Presentation layer supports many standards, which ensures that data is presented correctly. These include PICT, TIFF and JPEG for graphics, MIDI, MPEG and QuickTime for Video/Audio.

28)    What's the simplest way to remotely configure a router?


In cases when you need to configure a router remotely, the most convenient is to use the Cisco AutoInstall Procedure. However, the router must be connected to the WAN or LAN through one of the interfaces.

29)    What does the show protocol display?


-    routed protocols that is configured on the router
-    the address assigned on each interface
-    the encapsulation method that was configured on each interface

30)    How do you depict an IP address?


It can be done in three possible ways:
-    using Dotted-decimal. For example: 192.168.0.1
- using Binary. For example: 10000010.00111011.01110010.01110011
-    using Hexadecimal. For example: 82 1E 10 A1
----------------------------------------------------------------------------------------------------------------

Network Administrator Preparation Questions


Question # 1
Who is network administrator?
Answer:-
Network administrator is responsible for the maintenance of computer hardware and software systems that make up a computer network including the maintenance and monitoring of active data network or converged infrastructure and related network equipment.
Network administrators are generally mid-level support staff within an organization and do not typically get involved directly with users. Network administrators focus on network components within a company's LAN/WAN infrastructure ensuring integrity. Depending on the company and its size, the network administrator may also design and deploy networks.


Question # 2
What is network management?
Answer:-
Network management is the operation, administration, maintenance, and provisioning (OAMP) of networked systems. Network management is essential to command and control practices and is generally carried out of a network operations center.


Question # 3
List the layers of the OSI reference model?
Answer:-
There are 7 OSI reference layers:
*    Physical Layer
*    Data Link Layer
*    Network Layer
*    Transport Layer
*    Session Layer
*    Presentation Layer
*    Application Layer


Question # 4
Explain routers?
Answer:-
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.


Question # 5
Describe point to point link?
Answer:-
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.


Question # 6
What is link?
Answer:-


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.


Question # 7
Explain backbone network?
Answer:-
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.


Question # 8
Define LAN?
Answer:-
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.


Question # 9
Define node?
Answer:-
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.


Question # 10
Explain subnet mask?
Answer:-
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.


Question # 11
Explain the maximum length allowed for a UTP cable?
Answer:-
A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.


Question # 12
What can be considered as good passwords?
Answer:-
Good passwords are made up of not just letters, but by combining letters and numbers. A password that combines uppercase and lowercase letters is favorable than one that uses all upper case or all lower case letters. Passwords must be not words that can easily be guessed by hackers, such as dates, names, favorites, etc. Longer passwords are also better than short ones.


Question # 13
Define the number of network IDs in a class C network?
Answer:-
For a Class C network, the number of usable Network ID bits is 21. The number of possible network IDs is 2 raised to 21 or 2,097,152. The number of host IDs per network ID is 2 raised to 8 minus 2, or 254.


Question # 14
Tell me what happens when you use cables longer than the prescribed length?
Answer:-
Cables that are too long would result in signal loss. This means that data transmission and reception would be affected, because the signal degrades over length.


Question # 15
What common software problems can lead to network defects?
Answer:-
Software related problems can be any or a combination of the following:


*    Client server problems
*    Application conflicts
*    Error in configuration
*    Protocol mismatch
*    Security issues
*    User policy and rights issues


Question # 16
Tell me which protocol can be applied when you want to transfer files between different platforms, such between UNIX systems and Windows servers?
Answer:-
Use FTP (File Transfer Protocol) for file transfers between such different servers. This is possible because FTP is platform independent.


Question # 17
Explain the use of a default gateway?
Answer:-
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.


Question # 18
Define the proper termination rate for UTP cables?
Answer:-
The proper termination for unshielded twisted pair network cable is 100 ohms.


Question # 19
Explain netstat?
Answer:-
Netstat is a command line utility program. It provides useful information about the current TCP/IP settings of a connection.


Question # 20
What is ping?
Answer:-
Ping is a utility program that allows you to check connectivity between network devices on the network. You can ping a device by using its IP address or device name, such as a computer name.


Question # 21
Define peer to peer?
Answer:-
Peer to peer are networks that does not reply on a server. All PCs on this network act as individual workstations.


Question # 22
Tell me what advantages does fiber optics have over other media?
Answer:-
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.


Question # 23
Can you please explain the difference between hub and a switch?
Answer:-
A hub acts as a multi-port 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.


Question # 24
Explain DNS?


Answer:-
DNS is Domain Name System. The main function of this network service is to provide host names to TCP/IP address resolution.


Question # 25
List the different network protocols that are supported by Windows RRAS services?
Answer:-
There are three main network protocols supported: NetBEUI, TCP/IP, and IPX.


Question # 26
How maximum networks and hosts are in a class A, B and C network?
Answer:-
1)    For Class A, there are 126 possible networks and 16,777,214 hosts
2)    For Class B, there are 16,384 possible networks and 65,534 hosts
3)    For Class C, there are 2,097,152 possible networks and 254 hosts


Question # 27
What is the standard color sequence of a straight-through cable?
Answer:-
Orange/white, orange, green/white, blue, blue/white, green, brown/white, brown.


Question # 28
Tell me what protocols fall under the application layer of the TCP/IP stack?
Answer:-
Following are the protocols under TCP/IP Application layer: FTP, TFTP, Telnet and SMTP.


Question # 29
Is it possible to connect two computers for file sharing without using a hub or router?
Answer:-
Yes, you can connect two computers together using only one cable. A crossover type cable can be use in this scenario. In this setup, the data transmit pin of one cable is connected to the data receive pin of the other cable, and vice versa.


Question # 30
Define ipconfig?
Answer:-
Ipconfig is a utility program that is commonly used to identify the addresses information of a computer on a network. It can show the physical address as well as the IP address.


Question # 31
Can you please explain the difference between straight-through and crossover cable?
Answer:-
A straight-through cable is used to connect computers to a switch, hub or router. A crossover cable is used to connect two similar devices together, such as a PC to PC or Hub to hub.


Question # 32
Explain client/server?
Answer:-
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.


Question # 33
What is networking?
Answer:-


Networking refers to the inter connection between computers and peripherals for data communication. Networking can be done using wired cabling or through wireless link.


Question # 34
Suppose when you move the NIC cards from one PC to another PC, does the MAC address gets transferred as well?
Answer:-
Yes, that's because MAC addresses are hard-wired into the NIC circuitry, not the PC. This also means that a PC can have a different MAC address when the NIC card was replace by another one.


Question # 35
What is clustering support?
Answer:-
Clustering support refers to the ability of a network operating system to connect multiple servers in a fault-tolerant group. The main purpose of this is the in the event that one server fails, all processing will continue on with the next server in the cluster.


Question # 36
Suppose if a network which contains two servers and twenty workstations, where is the best place to install an Anti-virus program?
Answer:-
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.


Question # 37
What is Ethernet?
Answer:-
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.


Question # 38
Give some drawbacks of implementing a ring topology?
Answer:-
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 reconfiguration's needed to be performed on a particular part of the network, the entire network has to be temporarily brought down as well.


Question # 39
Can you please explain the difference between CSMA/CD and CSMA/CA?
Answer:-
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.


Question # 40
What is SMTP?
Answer:-
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.


Question # 41
Define multicast routing?
Answer:-
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.


Question # 42
Explain the importance of encryption on a network?
Answer:-


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.


Question # 43
How are IP addresses arranged and displayed?
Answer:-
IP addresses are displayed as a series of four decimal numbers that are separated by period or dots. Another term for this arrangement is the dotted decimal format.  An example is 192.168.164.8


Question # 44
Explain the importance of authentication?
Answer:-
Authentication is the process of verifying a user's credentials before he can log into the network. It is normally performed using a username and password. This provides a secure means of limiting the access from unwanted intruders on the network.


Question # 45
What is tunnel mode?
Answer:-
This is a mode of data exchange wherein two communicating computers do not use IPSec themselves. Instead, the gateway that is connecting their LANs to the  transit network creates a virtual tunnel that uses the IPSec protocol to secure all communication that passes through it.

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