# Introduction to OSPF **URL:** \ **Category:** Lessons Discussion\ **Created:** [December 20, 2016, 10:26pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878 "2016-12-20T22:26:55Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [December 20, 2016, 10:26pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/1 "2016-12-20T22:26:55Z")
This topic is to discuss the following lesson: > **[Introduction to OSPF](https://networklessons.com/ospf/introduction-to-ospf)** > > This lesson explains the basics of OSPF, a link-state IGP routing protocol that builds a LSDB by exchanging LSAs. ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [October 6, 2013, 2:51am UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/2 "2013-10-06T02:51:27Z")
Hi Rene, Its really cool amazing way of explaining ospf you made it to soft easy to understand I really wish You all success in your carrier. Regards, Mustafa ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [October 6, 2013, 3:16pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/3 "2013-10-06T15:16:00Z")
I’m glad you like it! ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [November 21, 2013, 9:46am UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/4 "2013-11-21T09:46:38Z")
you know the actual way to teach. your lessons are very helpful than any other blogs and i love this site…Thank u very much. Go ahead…May god bless u. Regards Khalidh ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [November 25, 2013, 1:14pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/5 "2013-11-25T13:14:53Z")
Thank you for your kind words Khalidh! ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [December 19, 2013, 12:57pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/6 "2013-12-19T12:57:08Z")
Thank u very much for you lessons!!! I planned pass CCNA in May 2014. Thank you for you lessons!!! ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [August 5, 2014, 11:50am UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/7 "2014-08-05T11:50:04Z")
hello mr Rene i would like to thank you for making me to understand ospf concepts you are the best tutor and this is the best site for learning ccna thank you soo much have a great day ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [August 18, 2014, 11:36am UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/8 "2014-08-18T11:36:32Z")
Its really very much helpful for freshers. ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [August 25, 2014, 3:59pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/9 "2014-08-25T15:59:54Z")
Very good Information for quick learning ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [September 15, 2014, 6:48pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/10 "2014-09-15T18:48:53Z")
that was so useful thnx ---
**Author:** ![egbevanwatson](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/e/cc9497/32.png) [@egbevanwatson](https://forum.networklessons.com/u/egbevanwatson)\ **Post date:** [November 19, 2014, 7:25pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/11 "2014-11-19T19:25:26Z")
The one exclusive sign of thorough knowledge is the power of teaching.Rene your teaching styles is quite explecite and down to earth.You videos are so wonderful and easy to understand. I have a question regarding the reference bandwidth.If i am not making a mistake,you made mention about some older version of the cisco ios using a reference bandwidth of 100Mbit and the Newer versions 1000 Mbit.I was curios to know how the reference bandwidth can be verified on a cisco ios. Thanks in advance ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [November 20, 2014, 10:27am UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/12 "2014-11-20T10:27:39Z")
Hi Emmanuel, Thanks for your kind words 🙂 Glad to hear you like it! You can find the reference bandwidth with the **show ip ospf** command, for example: ```auto R2#show ip ospf | include Reference Reference bandwidth unit is 100 mbps ``` Rene ---
**Author:** ![egbevanwatson](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/e/cc9497/32.png) [@egbevanwatson](https://forum.networklessons.com/u/egbevanwatson)\ **Post date:** [November 20, 2014, 1:41pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/13 "2014-11-20T13:41:30Z")
Thanks rene.your assistance was well appreciation.Keep on with the good work. Kind Regards Emmanuel ---
**Author:** ![egbevanwatson](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/e/cc9497/32.png) [@egbevanwatson](https://forum.networklessons.com/u/egbevanwatson)\ **Post date:** [November 20, 2014, 1:42pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/14 "2014-11-20T13:42:00Z")
Thanks rene.your assistance was well appreciated.Keep on with the good work. Kind Regards Emmanuel Read more: [https://networklessons.com/ospf/introduction-to-ospf/#ixzz3JcFqTtYF](https://networklessons.com/ospf/introduction-to-ospf/#ixzz3JcFqTtYF) ---
**Author:** ![dineshnk.it](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/d/3bc359/32.png) [@dineshnk.it](https://forum.networklessons.com/u/dineshnk.it)\ **Post date:** [December 11, 2014, 7:49pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/15 "2014-12-11T19:49:12Z")
Hi Rene, Excellent way of teaching… From today, you are my inspiration of teaching cisco topics to others 🙂 ---
**Author:** ![praveenapr30](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/p/e19adc/32.png) [@praveenapr30](https://forum.networklessons.com/u/praveenapr30)\ **Post date:** [December 11, 2014, 10:01pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/16 "2014-12-11T22:01:53Z")
HI Rene, nice explanation ..🙂 i have a question. if we have 16 equal cost paths to a specific destination , all these 16 paths will be placed in routing table? and one more thing is that, cost =100Mbps/link bandwidth. if the link is gigabit Ethernet, then the cost will be in fractions right, so how will it managed? “To make paths equal cost, change the “cost” of a link” can u give me an example of the same. Thanks, praveen ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [December 15, 2014, 8:11pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/17 "2014-12-15T20:11:39Z")
Hi Praveen, Yes that’s right, if you have 16 equal cost paths then all of them will be in the routing table. By default OSPF will only use 4 equal cost paths so you’ll have to change this if you want to use more than 4. About the cost, that’s a good question…if the reference bandwidth is 100Mbit then a Gigabit link would have a cost of 0.1. Cisco IOS however doesn’t use a cost lower than 1 so a FastEthernet and Gigabit link both will have a cost of 1. If you use Gigabit links, it’s better to change the “reference bandwidth” to Gigabit…this means Gigabit will have a cost of 1 and FastEthernet a cost of 10. Rene ---
**Author:** ![benedictadjei](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/b/cc9497/32.png) [@benedictadjei](https://forum.networklessons.com/u/benedictadjei)\ **Post date:** [January 9, 2015, 8:30pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/18 "2015-01-09T20:30:19Z")
Hi Rene thanks very much for my last response on the Networking designing recommendation. I will like to quickly ask if you have taken two test of the old ccnp exams in my case 642-802 and 642-813, and i dont take the 642-832 before it expires, would i loss the first two exams, or can i take the new tshoot to make me a full ccnp thank you. ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [January 14, 2015, 2:06pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/19 "2015-01-14T14:06:28Z")
If your 642-802 and 642-813 certifications are valid then you can do the new TSHOOT V2 exam and you will be fully CCNP, that’s no problem at all. ---
**Author:** ![wisamani](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/w/9fc348/32.png) [@wisamani](https://forum.networklessons.com/u/wisamani)\ **Post date:** [February 6, 2015, 12:32am UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/20 "2015-02-06T00:32:30Z")
Very Helpful, Thanks Rene. [Next page](https://forum.networklessons.com/t/introduction-to-ospf/878.md?page=2)