OSPF Hello Packets :: Area Types (Stub/NSSA) :: BDR/DR

OSPF Hello Packets :: Area Types (Stub/NSSA) :: BDR/DR :: Practical OSPF

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Күн бұрын

In this lesson we take a look at Hello Packets and explore all the items they contain. Understanding the content of a Hello packet will show us the requirements for OSPF Routers to become Neighbors with each other.
The Hello packet also includes Area Type and BDR/DR/Priority, which allows us to explain the ideas of Stub areas and Not So Stubby Areas (NSSA). As well as the concepts of the Designated Router (DR), Backup Designated Router (BDR), and the Priority Number.
Here are all the contents of a Hello packet that are explained: Router ID, Area ID, Authentication Data, Network Mask, Hello Interval, Dead Interval, Area Type, Priority Number, Designated Router, Backup Designated Router, and Active Neighbors fields.
This is Lesson 3 of the Practical OSPF series:
• Practical OSPF
00:00 - Start
00:12 - Hello Packet Introduction
01:43 - Router ID
02:36 - Hello Interval / Dead Interval
03:39 - Neighbors Field
05:03 - Area ID
05:18 - Authentication Data
05:51 - Network Mask
06:03 - Area Type / DR / BDR Introduction
06:19 - Normal Area, Stub Area, Not So Stubby Area (NSSA)
11:20 - Designated Router, Backup Designated Router, Priority
14:13 - When does DR/BDR election take place? Multi Access Links
15:35 - What fields must Match in Hello Packets?
17:47 - Outro
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Пікірлер: 136

@PracticalNetworking 2 жыл бұрын

📌 *More free preview lessons from the Practical OSPF course:* pracnet.net/ospf 📌 *Want even more? Check out the full course:* pracnet.net/ospfcourse 📌 *CCNA Resources:* pracnet.net/ccna 📌 *Learn Networking:* pracnet.net/nf 📌 *Learn & Practice Subnetting:* subnetipv4.com

@ahmed.benaros Жыл бұрын

Never heard of any thing so clear, simple and valuable than this. Thanks

@PracticalNetworking Жыл бұрын

Cheers, Ahmed !

@papie5151 3 ай бұрын

I'm a visual learner and this channel and lessons have really helped me in digesting several technical topics.

@matthewcardinal4186 Жыл бұрын

I really hope some company sponsors your content - I would buy something you mentioned just because you are such an amazing teacher!

@randyyihsienhan Жыл бұрын

Best OSPF area type explanation I ever read, especially for stub and NSSA. Thanks a lot for helping to understand the concept within 5 minutes!

@PracticalNetworking Жыл бұрын

Thank you for the kind note. GLad you enjoyed the video, Randy =)

@randyyihsienhan Жыл бұрын

I feel your series is even better than INE and Udemy paid program, that is really awesome work.

@PracticalNetworking Жыл бұрын

@@randyyihsienhan

@erikasantos2595 5 ай бұрын

You have an amazing teaching ability. Content is so well-organized, clear and concise! Thank you!

@afsala.a.6598 2 ай бұрын

Awesome video as well as the series too. Really helpful, easy to follow and understanding. Thank you so much.

@gd2860 3 ай бұрын

Hell of a video series. Im hooked.

@azadkumar6740 2 жыл бұрын

Nicely and clearly explain every pieces. your teaching methods it that much good that in a single day I watch more than 40 videos.

@PracticalNetworking 2 жыл бұрын

Ha! Awesome. Thank you. Glad you've enjoyed my content, Azad =). 40 videos! Wow, you've earned a break =).

@ajaxSAF 2 жыл бұрын

Dude you're really good at this

@PracticalNetworking 2 жыл бұрын

Thank you =)

@guybouaka 2 жыл бұрын

I am finally be able to make a clear distinction between Stub and NSSA. Thank you very much

@PracticalNetworking 2 жыл бұрын

Awesome, Guy! Happy to hear that =).

@olegasgolubevas8773 3 ай бұрын

I would highly recommend it to everyone who is studying OSPF protocol.

@PracticalNetworking Ай бұрын

@DIY-ct1si 2 жыл бұрын

This is the best ospf details I have seen in KZfaq.. very good summarized, just waiting for BGP, QOS series.

@PracticalNetworking 2 жыл бұрын

Glad you've enjoyed it =). Hope you enjoy the rest of the videos in the series as well. kzfaq.info/sun/PLIFyRwBY_4bSkwy0-im5ERL-_CeBxEdx3

@rocdiva530 Ай бұрын

Crystal clear content! Thanks

@sergioalcantar3290 9 ай бұрын

Boy, do I like this training!

@PracticalNetworking 9 ай бұрын

Sergio! I've enjoyed seeing your positive comments on the videos in this series =) Glad you're enjoying them!

@informationstechnologie2478 Жыл бұрын

Thank you for all your efforts you're doing Ed! I really appreciate these handy animations and your so simple way to explain that complex processes. You can wrap it up like no one else ever did. I'm truly amazed!!

@PracticalNetworking Жыл бұрын

Thank you for the kind words. If you're willing... Could you do me a favor? Do you mind sharing this video on Linked In, Reddit, Twitter, Facebook, or any other social media you use? As an independent creator, that would be an _enormous_ help, and I would appreciate it _greatly_ .

@ershadramezani6716 6 ай бұрын

Awesome OSPF videos! Really useful and well explained. Thanks a ton for sharing!

@PracticalNetworking 4 ай бұрын

You're very welcome, thank you for your support.

@ihabsukar2469 6 ай бұрын

Great Lessons love the explanation !!!

@stepankarel903 2 жыл бұрын

Awesome video, thank you for the knowledge. I would be more than happy to support you in the future lessons and make it obvious for you that your work really pays off - trust me, it's just so much more pleasant to learn from your videos rather than some indian youtubers that barely understand the topic and try to speak it out. *Once again, keep it up!*

@PracticalNetworking 2 жыл бұрын

Hi Stepan, Thanks for the kind words =). I'd love to continue creating this content. The best way to support me is to share this content with any audience you think might benefit from it. Beyond that, I also have some courses you can purchase here: classes.pracnet.net/ Either way, thanks for the kind note. Glad you are enjoying the OSPF series!

@MichaelWilliams-vf9vn Жыл бұрын

Nice. Clean , direct, easy to follow and understand. Thanks!

@PracticalNetworking Жыл бұрын

You're welcome, Michael.

@bhattbhaumik3266 Ай бұрын

clear, concise and to the point

@aminelfeky 7 ай бұрын

Love your videos Ed. Your content and your approach to teaching is amazingly unique. Would love a BGP deep dive series

@edpressley653 Жыл бұрын

Great lesson, the way you break this down makes it easy for me to understand.

@PracticalNetworking Жыл бұрын

Thank you, Ed. Glad this is helping OSPF makes sense =). Don't forget to check out the rest of the OSPF lessons either: kzfaq.info/sun/PLIFyRwBY_4bSkwy0-im5ERL-_CeBxEdx3

@megaskater815 Жыл бұрын

Thanks for posting this video! It's easy to understand and your videos keep me motivated to learn more!

@PracticalNetworking Жыл бұрын

Awesome, glad to hear! Keep up the good work!

@ohad8736 Жыл бұрын

best Networking teacher out there

@PracticalNetworking Жыл бұрын

Thank you for the kind words, Ohad. Cheers =)

@pallavi8388 2 жыл бұрын

Beautifully explained. Thanks

@PracticalNetworking 2 жыл бұрын

You're welcome =)

@Therojasvictor 10 ай бұрын

Excellent teaching.

@browneyedbabes7863 Жыл бұрын

Awesome video series! 👏🎬

@PracticalNetworking Жыл бұрын

Glad you enjoy it!

@alexandrkovalsky1711 Жыл бұрын

great video!

@mohamadtalbi6855 Жыл бұрын

thank you of the great content

@lifeisbeautiful7882 2 жыл бұрын

very perfectly explained.Thanks

@PracticalNetworking 2 жыл бұрын

Cheers =). Glad you enjoyed it !

@RishiRap Жыл бұрын

Nice explanation!

@adedejiemmanuel1 2 жыл бұрын

This is a good treaching. Thank you.

@PracticalNetworking 2 жыл бұрын

You're welcome, Azza! 👋

@user-jn5fu4vn1q 3 ай бұрын

Dear Sir, you have very tactfully explained, but plz when you upload the video with multiple language so it is better to understand students.

@rohanofelvenpower5566 Жыл бұрын

this series is very educational and sexum

@arshdeep1286 Жыл бұрын

Thanks so much for your help. God bless you professor

@PracticalNetworking Жыл бұрын

You are very welcome

@subee128 5 ай бұрын

Thank you very much 🙏🏻

@Bandalorian Жыл бұрын

Thanks for this Ed

@PracticalNetworking Жыл бұрын

You're welcome, Ursura =)

@Don-Carillo 2 жыл бұрын

Great video, Ed. The way you break it down is great and makes it easy to absorb. The simple explanation of Area types has already helped more than most videos and I have seen a lot. Love the adjacency non match info too. Does the MTU need to match too or is that somthing else?

@PracticalNetworking 2 жыл бұрын

Hey Don. Thanks for the note. Glad you enjoyed this angle for Areas Types =). The MTU one is tricky. In my labing I've found where the MTU mismatch causes a neighbor adjacency to fail, and other times where it doesn't. In any case, MTU isn't actually in the Hello Packets, it's in the DBD packets, so I didn't include information about the MTU in this video. (which honestly, already went much longer than I expected, ha!)

@joshuadalton6063 4 ай бұрын

MTU should match per the RFC, but keep in mind how different vendors do/don't include ethernet header in the value, so it might be 4-8bytes different also with MPLS or other encapsulation.

@mohanrajc3518 10 ай бұрын

Thank you !!!

@dnj20 Жыл бұрын

great video

@PracticalNetworking Жыл бұрын

Cheers DNJ =). Thank you again.

@poojajaiswal4699 Жыл бұрын

Thank you finally concept is clear

@PracticalNetworking Жыл бұрын

Glad to hear, Pooja. Hope you enjoy the rest of the OSPF series as well: pracnet.net/ospf

@poojajaiswal4699 Жыл бұрын

@@PracticalNetworking sure I have started thanks😊

@kandapahala Жыл бұрын

Great , Thanks

@PracticalNetworking Жыл бұрын

You're welcome, Gihan.

@antifics 2 жыл бұрын

Muchas Gracias!

@PracticalNetworking 2 жыл бұрын

De nada =)

@asish4ever 5 ай бұрын

Thank you !

@PracticalNetworking 5 ай бұрын

You're welcome!

@karanvyas5155 2 жыл бұрын

Awesome video sir

@PracticalNetworking 2 жыл бұрын

You're welcome, Karan!

@ifeelkiing Ай бұрын

Holy moly!

@afshin9 2 жыл бұрын

amazing👏

@PracticalNetworking 2 жыл бұрын

@abdirahmanabdullahi1150 2 жыл бұрын

ed thanks for great explntion

@PracticalNetworking 2 жыл бұрын

You're welcome, Abidirahman =)

@user-wx7ny3pw8t 7 ай бұрын

thank you mate

@Niggro07 2 жыл бұрын

Thanks!!

@PracticalNetworking 2 жыл бұрын

You're welcome =)

@abdulferoz8199 Жыл бұрын

Thanks 😊

@montassirben8560 8 ай бұрын

Thank you

@BekoIQ 2 жыл бұрын

You should make paid course for ccna , ccnp because you will the best trainer trust me

@PracticalNetworking 2 жыл бұрын

I think about committing to something like that all the time.

@rapnetwork4170 Жыл бұрын

Thank you very much for the great videos. Helped me a lot on my job interview process. Are there any plans for future BGP series? =)

@INIOBONGUDOFIA Жыл бұрын

Bravo

@drmanhattan225 2 жыл бұрын

Great videos. Any plans to make a CCNP training series?

@PracticalNetworking 2 жыл бұрын

I've thought about it =). No plans at the moment.

@stepankarel903 2 жыл бұрын

@@PracticalNetworking CCNP series would be great, as I'm entering a university soon and am planning to catch up where I've finished in high school - CCNA :-)

@guibinli1336 2 жыл бұрын

amazing videos to teach network knowledge, would you make lesson for advance network like BGP, VXLAN, etc ?

@PracticalNetworking 2 жыл бұрын

Possibly, yes. BGP has come up a few times as a suggestion =)

@jyotirmoy8082 Жыл бұрын

Awesome, kindly if you have made any Wireshark packet analysis & any interview preparation I believe that will be helpful for many people :) Thanks

@ChiragPatel-bw2rr 2 жыл бұрын

Thanks Ed, prefect visual explanation, do you have transcript of this series on your website ? cheers

@PracticalNetworking 2 жыл бұрын

Glad you enjoyed it, Chirag. I'm afraid I don't have a full transcript. A lot of the content of the first 5 videos has been converted to article format, if that is helpful: www.practicalnetworking.net/stand-alone/ospf-training-course-free-m1/

@devpatel2102 2 жыл бұрын

@@PracticalNetworking thank you so much 🙏

@PracticalNetworking 2 жыл бұрын

@@devpatel2102 You're welcome =)

@mohamedhaneef6379 10 күн бұрын

Is Area Type part of the hello packet ? As usual amazing explanation :) I recall reading that the Hello Packet does not explicitly mention the area type. Could you please confirm? Thanks

@priya34101 Жыл бұрын

nice

@PracticalNetworking Жыл бұрын

Thank you, Priya.

@Alestrix76 Жыл бұрын

Lots of useful and interesting information, thanks! Some questions remain though: ~~- If the Hello Packet contains the sending router's RouterID and the list of neighbours, what new information does R2 in 12:09 have to send to R3/4/5 if only R1 has learned something new? R2's Hello-Packet would still look the same, no? Or are we simply talking of forwarding received Hello-Packets? If so, will the source IPs remain the same or will they be replaced by the relaying router's IP?~~ (forget that, that was LSUs, not Hello Packets) - 16:00 matching of Hello Interval and Dead Interval --> Is this something that is enforced programmatically or is it just best practice? Also, how I understood 3:16 is that R2 tells R1 after what time R1 should assume R2 to be dead, which only needs to be more than the Hello-Interval in order to avoid flapping. No need for R1 to tell R2 the same numbers.

@PracticalNetworking Жыл бұрын

Good questions. The new information wouldn't be contained in a Hello Packet, but in a LSU. The Hello packet would largely be the same. Remember, OSPF is about sharing routes, so in this context the "new information" is learning of a new route. Since R1 is not connected to R3/4/5, that new route must be propagated through R2. Re Hello/Dead intervals is enforced programmatically -- the neighbors will not form an adjacency if they disagree on the hello/dead timers. While I see your point that it _could_ work without an exact match... the creators of OSPF decided to require an exact match. Hence, this is the rule enforced programmatically =).

@abdelaalimhoufini8628 Жыл бұрын

thank you for this great explanation but i have one question why would we interconnect more than two router via a switch ?

@PracticalNetworking Жыл бұрын

I would say it's pretty rare... but it _could_ happen, therefore OSPF has to account for it.

@amitmohapatra292 Жыл бұрын

hy ! actually i have got a doubt that area is basically used to restrict the domain of the lsa's so that means area 88 is going to have 10 routes right ? but when area type is normal its becoming 30 how ?

@PracticalNetworking Жыл бұрын

The answer to your question is in the Areas video: kzfaq.info/get/bejne/ebNpdc93raiXoWg.html Basically, even though the route is in another area, each area still needs to know about the route (so it can send packets to that area). The area boundary limits the propagation of _unnecessary_ changes if they occur in a foreign area. More details in the linked video.

@vladislavkaras491 Жыл бұрын

Very great explanation! I have two questions: 1) 10:30 Is it 80 or 81 route on NSSA? 50 from RIP, 10+10+10 from OSPF (total 80) and then how do we reach EIGRP? Is it +1 from default route (total 81) or is it 1 route from Area 99 that goes to EIGRP? 2) 14:23 Does DR & BDR election happens on every multi-access link or election happens per area? Thus, one area have only 1 DR and 1 BDR or can it have multiple, because there are multiple multi-access links such as Ethernet? Thanks for the video!

@PracticalNetworking Жыл бұрын

Good questions! 1. It's 80 by default, and then you as the Admin can choose how to apply your default route. OSPF itself, however, would only account for 80 routes. 2. The DR/BDR election happen for each multi-access link. You can absolutely have many DR's in a single area (you'll always have one per multi access link). Cheers!

@vladislavkaras491 Жыл бұрын

@@PracticalNetworking alright, thank you for your answers!

@kimosaid3221 2 жыл бұрын

👏👏👏

@PracticalNetworking 2 жыл бұрын

Cheers!

@abdirahmanabdullahi1150 2 жыл бұрын

Salaama

@joshuadalton6063 4 ай бұрын

At 10:52 if the default route for area88 was R5, then neither R5/R6 would be able to reach the 100 EIGRP routes behind R7, no?

@espartaco2028 Жыл бұрын

I´m leaving a comment to help your stats because your videos are excellent, you´re hot. Your voice is clear as well. The lessons well thought out.

@PracticalNetworking Жыл бұрын

Thank you for supporting this channel, and the kind words =).

@majiddehbi9186 20 күн бұрын

hello gtreat guy

@medosasa4580 3 ай бұрын

Is what is meant by the default path...a path that works using the Static Default Routing Protocol?...or what is it intended...help please...and thank you for your excellent explanation

@PracticalNetworking 3 ай бұрын

I don't think "default path" has an objective/absolute definition. It likely context based. -- the default path OSPF uses -- the default path from the default route -- the default path towards the internet etc...

@medosasa4580 3 ай бұрын

@@PracticalNetworking But does this default path make the stub area able to send and receive data from the area that has a protocol other than OSPF??.... And how can this default path reduce 30 paths or networks to one path or one network, as you explained In the example??...Does OSPF say that the paths are converted to one default path automatically once I make the “Stub Area” or do I configure it manually?......and Does the default route exist on the topology table of the ABR router only?.... and Thank you for what you do for us🤍

@reggie9550 Жыл бұрын

Sir, are these available on Udemy, would be great to have them there as well. These series are great learning.. thx

@PracticalNetworking Жыл бұрын

Not at the moment =)

@arrindamroy501 2 жыл бұрын

Hello Sir .... I have gone through you networking fundamental MODULE 1 course and I am interested to buy the entire course . Kindly let me know how can I procure it. Thank you

@PracticalNetworking 2 жыл бұрын

The Networking Fundamentals course hasn't been created. I'm waiting to see how much reach Module 1 gets before committing the time / energy to create the full course. The best way to make it a reality is to help spread the word about the free Module 1 videos.

@parheliaa 2 жыл бұрын

An MTU and link types also have to match to get an adjacency. Very often, this is overlooked (especially in multi-vendor projects), and

@PracticalNetworking 2 жыл бұрын

Yea, great point. I went back and forth about including this, but opted against it since the MTU isn't shared in the Hello packet, it's only shared in the DBD packets. It's a point I plan to circle back to later in the series.