ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

7 layer model – IT help desk interview questions and answers

Updated on February 7, 2012

7 Layer model of a network

seven layer model representing the data transmission over the internet
seven layer model representing the data transmission over the internet

Common IT Help desk interview questions and answers

In my earlier hub on help desk interview questions, I have mentioned some of the important interview questions asked in a helpdesk interview. In this hub, I want to talk about the 7 layer model, which is an important part of any network admin or system admin interview process. If you are looking for an IT help desk position, or a basic system admin position, it is important to have a thorough understanding of this seven layer model so that you can answer the common interview questions with authority. This is an interesting topic for others too as you would enjoy knowing the process involved with the communication over the internet.

What is a 7 layer model in a network?

Ever wondered how your mails or message from your computer reach the recipient on the other end? This data transmission is based on the 7 layer model. This is simply referred as APSTNDP. Application layer, Presentation later and Session layer are the top three parts of the seven layer model and represent the dynamic communication. The other 4 layers include Transport Layer, Network Layer, Datalink Layer and the Physical layer which talk about the physical communication of the data over the network. Let us look into more details of this 7 layer model. I will try to put this into simpler language so that everyone can understand this concept easily.

Application Layer

This is the top level layer in the seven layer model. This layer is responsible for identifying the available communications and resources and synchronizing the communication. For instance, if you browse the internet with the help of Google Chrome or Mozilla Firefox, the application layer initiates the communication part and identifies the availability of a port to communicate the HTTP protocol.

Presentation Layer

The second layer in the 7 layer model is the presentation layer. This layer takes care of the presentation part of the data which involves encoding, encrypting and other data management functions. For instance, if you want to send a zip file to another recipient, this presentation layer presents that data in a user friendly format to the application layer. Similarly, the data received from the application layer is encrypted in the right manner so that it is exchanged between the networks.

Session Layer

The third and important part of the seven layer model is the Session Layer. This layer is responsible for handling multiple communication sessions. If you have used a particular application or service in the application layer, there is a specified time after which the session gets timed out. This is the task of the session layer to maintain the integration of the data.

These 3 layers are a part of the application wherein the session layer initiates a session, the presentation layer presents that data in the correct format to the application layer where the actual interaction with the end user is being done.

Transport Layer

The transport Layer takes care of the transportation of the data between end users. This layer collects the data from the network layer and sends this data to the session layer using the appropriate data transportation protocol. Transport Layer acts as an intermediate between the top 3 layers and the bottom 3 layers of the 7 layer model. This layer controls the data flow and regulates the amount of data being transmitted, based on the receiving capabilities of the end user. There are several transport layer protocols like TCP, FTP, UDP, DNS, HTTP IMAP, HTTPS and POP3. TCP is the most commonly used transmission protocol.


Network Layer

Network Layer is an essential portion of this seven layer model wherein the switching and the routing procedures of the data is being done. The data received from the Physical and Datalink layers is routed into the right path in this layer. In simpler words, the physical data is converted into the logical data.

Datalink Layer

Datalink Layer receives the physical data from the Physical Layer for encoding and decoding over the network. This layer is again divided into two, namely Media Access Control Layer and Logical Link Control Layer. Media Control Layer takes care of the data access and permissions of each computer on the network and the Logical Link Control Layer takes care of the data flow.

Physical Layer

The Physical Layer is the important part of the 7 layer model which takes care of the actual transmission of the data and represents the physical equipment used for the data transmission. Modem, Hub, Router and other network hardware form this physical later entity. The physical data is collected through these devices at this layer and then transmitted to the datalink layer for processing it.

These are the 7 parts of the seven layer model which are responsible for the data transmission between networks. It is important to understand this 7 layer model because it helps you in error handling. When you break down this process into 7 layers, you can identify at what level the error is occurring so that effective resolution can be implemented.

Comments

    0 of 8192 characters used
    Post Comment

    • profile image

      PM 

      6 years ago

      This gives a very good understanding to the layman!

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)