ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Shortest Path Routing OSPF & Dijkstra's Algorithm - Finding Shortest Path in a Network using MATLAB

Updated on July 2, 2009

OSPF - A little theory first

OSPF or Open Shortest Path First is a dynamic routing protocol, it is a link state routing protocol and is part of the interior gateway protocols group. OSPF is similar to RIP but unlike RIP that keeps track of the closest router for each destination address OSPF keeps track of the complete network topology and all the nodes and connections within that network.

The basic workings of the OSPF routing protocol are as follow

- Startup

When a router is turned on it sends Hello packets to all neighboring devices, and the router receives a Hello packets in response. From here routing connections are synchronized with adjacent routers that agree to synchronize.

- Update

At regular intervals each router will send an update message called its “link state” to describing its router database to all other devices. So that all the routers connected together have an up to date description of each topology that is connected to each router.

- Shortest path tree

Each router will calculate a mathematical data structure called “shortest path tree” that describes the shortest path to the destination address, this is where OSPF gets it name, it will try to open the shortest path first.

OSPF routing protocol is a very important protocol to consider when setting up routing instructions on your network. As OSPF gives the routers the ability to learn the most optimal (shortest) paths it can definitely speed up data transmission from source to destination.

Even with these capabilities OSPF may not be ideal in a network that is prone to bottlenecks or increased traffic across specific parts of the network.

Determining Shortest Path for your Network

For this example I will use the 10 node network I used for my max flow min cut example in my other hub. Instead of link capacities the numbers across each link represent distances or weights.

First I create my network design using the command in matlab to create a matrix

cm = sparse([1 1 2 2 3 4 4 5 5 6 7 8 9 9],[2 3 3 4 5 6 7 6 7 8 9 10 8 10],[15 10 3 8 9 7 5 6 2 12 10 6 10 8],10,10)

note: for more on how to setup your matrix look at Max Flow Min Cut Algorithm HUB

The Network will look like the following to Matlab ->

Source node 1 to destination node 10

Shortest Path

To determine the shortest path I executed the following command

[dist,path,pred] = graphshortestpath(cm,1,10)
with output:

dist =39

path =1 3 5 7 9 10

pred =0 1 1 2 3 5 5 6 7 9

There you have it the shortest path from source to destination, of course this is an extremely easy example
There you have it the shortest path from source to destination, of course this is an extremely easy example

Comments

    0 of 8192 characters used
    Post Comment

    • profile image

      hanaa 

      3 years ago

      I want find shortest path between nodes , but with a condition on the edges for finding shortest path. how can i do it ?

    • profile image

      chalue 

      7 years ago

      What is the shortest distance between Node 1 to Node 5

    • profile image

      Surf 

      7 years ago

      I've written better algorithms myself..

    • profile image

      apurva sachan 

      7 years ago

      how cn we obtain the dynamic graph changing after certain t sec. Nd den apply ospf in each t sec.

    • profile image

      Babai 

      7 years ago

      1) Give the codes for cross layer design using Matlab.

      2) Give the Matlab codes for Congestion control using TCP/IP

    • expectus profile imageAUTHOR

      expectus 

      8 years ago from Land Downunder

      I will have a look for it used to have it, but a google search should get the same results

    • profile image

      krish 

      8 years ago

      how about in c++

    • expectus profile imageAUTHOR

      expectus 

      8 years ago from Land Downunder

      This is done in MATLAB , it depends what format you want the code in?

    • profile image

      Sushma 

      8 years ago

      how to get the code of this? just explanation is given... how to get dijkstra's algorithm code?

    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)