OSPF LSA - the BEST explanation of the Types of OSPF LSAs

Рет қаралды 36,540

Күн бұрын

OSPF Routers share routing information using Link State Advertisements, or LSAs. There are 5 main types of OSPF LSAs, and all of them are used to populate a Router's the Link State Database (LSDB).
In this video, we illustrate and explain the 5 main types of OSPF LSAs:
Type 1 LSAs - Router LSA
Type 2 LSAs - Network LSA
Type 3 LSAs - Summary LSA
Type 4 LSAs - ASBR Summary LSA
Type 5 LSAs - External LSAs
This is lesson 9 of the Practical OSPF series. The full series is available here:
• Practical OSPF
00:00 - Lesson 9, 10, 11, and 12 - OSPF LSAs Types
00:50 - Topology Introduction
01:15 - Type 1 LSAs - Router LSA
02:00 - Type 2 LSAs - Network LSA
02:26 - Simple Illustration of Type 1 and Type 2 LSAs
05:19 - Type 3 LSAs - Summary LSA
08:41 - INTRA Area Routes vs INTER Area Routes vs External Routes
09:36 - Type 5 LSAs - External LSA
11:11 - Type 4 LSAs - ASBR-Summary LSA
13:29 - Summary / Outro / Next Lesson
=== PRE-REQUISITES ===
LSAs and LSDBs:
• OSPF Framework & OSPF ...
OSPF Areas and OSPF Types of Routers:
• OSPF Areas and OSPF Ty...
Designated Routers and Backup Designated Routers (DR / BDR):
• Designated Router // B...
================
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www.practicalnetworking.net/i...
🎯 Full Practical OSPF Series ➡️ pracnet.net/ospf:
• Practical OSPF

Пікірлер: 143

@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

@kingafadll2006 8 күн бұрын

I want to say thank you, I am bluffed by how you have explained that, I have purchased many of CCNA & CCNP courses, but no one has explained it the way you did. Thank you

@scottspa74 2 жыл бұрын

Ed, you're a bit of a savant. I will never understand how you can have such a grasp of all of this. Your instruction is fantastic, I will have to review this when I'm not half asleep, but what you share with us is AMAZING.

@PracticalNetworking 2 жыл бұрын

Thanks for the kind words, Scott =). Yes, definitely let us know what you think when you get back to this video. Cheers !

@usmanhamid7908 Жыл бұрын

All of your videos are presented with such a great explanation and animation that it makes confusing concepts very clear, very quickly. Thanks!

@abulzawabe3 Жыл бұрын

I can't thank you enough for this clear and brief lecture. That was fantastically done!

@rickwiers1905 Жыл бұрын

This is the best video I have seen about LSA's in a simple understandable way!

@aler3119 Жыл бұрын

Best explanation I have come across so far! Thanks for the great work.

@PracticalNetworking Жыл бұрын

You're very welcome, Ale. Cheers.

@lokeshreddysura6836 Жыл бұрын

I have been searching for almost 7 years to know what is the LSA Types differences and their nonsense theory and you nailed it in a shot. Superb. It feels like no instructor knows what exactly LSA's are except you.

@Arvindkumar-vs6mo 8 ай бұрын

Watching OSPF topics on your channel. One of the Best teacher. You are awesome in conveying the information with pictorial form.

@dc4life_956 9 ай бұрын

WOW. Best content I've run across. Greatly appreciate your style.

@tonicshahov8153 Жыл бұрын

Your explanation of LSA types is trully best, as you promised in description!

@PracticalNetworking Жыл бұрын

Glad you enjoyed it, Tonic. Thank you for the kind words.

@mikemoman Жыл бұрын

Brilliant. You explain these topics so well. Thank you.

@user-vg5gn3zp2m 5 ай бұрын

excellent presentation. Thanks!

@DhrubRajGiri01 5 ай бұрын

Love it, short summary of lsa

@idowuaina7674 Жыл бұрын

Your videos are simply the best I have come across. Rich in content and details

@PracticalNetworking Жыл бұрын

Thank you for the kind note, Idowu. Glad you have enjoyed this content.

@fabianravasila6802 Жыл бұрын

Incredibly well explained. Ty!

@babb4214 2 жыл бұрын

Good stuff! Thanks for putting the work in to share this info. Very helpful

@PracticalNetworking 2 жыл бұрын

Glad you enjoyed it =).

@calcen_ Жыл бұрын

It is helpful as I am currently preparing for CCNA. So I am gonna jump to the Type1 and 2 LSA video of yours:) Thanks a lot

@goldisss Жыл бұрын

That was really the BEST explanation. Thank you.

@hampusgotlind2357 Жыл бұрын

You are such a legend. Makin everything so easy to understand! Thank you =]

@PracticalNetworking Жыл бұрын

You're very welcome, Hampus.

@davidjimenez2992 Жыл бұрын

Absolutely amazing how you explain this topic

@PracticalNetworking Жыл бұрын

Glad you enjoyed it, David.

@laminceesay1435 Жыл бұрын

This is a great lesson, Thank you.

@GokhanDoymaz-oi7lx 2 ай бұрын

Perfect explained LSA Types 1,2,3,4,5

@PracticalNetworking Ай бұрын

Thank you, Gokhan =)

@aniswlidi2012 7 ай бұрын

Greate explanation about the LSAs. Thanks

@samueltetteh7133 Жыл бұрын

Great presentation. You simplified every thing .thanks

@PracticalNetworking Жыл бұрын

You're welcome, Samuel !

@DarkArchery1511 5 ай бұрын

Thank you very much. I really appreciate your explanation with moving diagrams. I currently prepare myself for an exam and it was really hard for me to imagine how it works just out of the slides. Before this video I didn't even understand where the LSA are all send to.

@arii4369 8 ай бұрын

Thanks for the explanation it was really helpful!

@h4zedolores 2 ай бұрын

Thank you very much, such an amazing explanation

@yasaralzakout7691 Ай бұрын

Excellent work and clear explanation. Thank you.🤓

@PracticalNetworking Ай бұрын

Thank you so much for supporting the channel, Yasa =) I'm thrilled to hear you enjoyed this content.

@manoj121979 Жыл бұрын

Excelent explanation about LSA

@Noah-xn5th 6 ай бұрын

Yes, this is indeed the best explanation.

@u82zar 6 ай бұрын

Sorry to be that person but there are actually 11 types of LSAs (OSPF). LSA Type 1 Router LSA LSA Type 2 Network LSA LSA Type 3 or 4 Summary LSA & ASBR LSA LSA Type 5 Autonomous System External LSA LSA Type 6 Multicast OSPF LSA Type LSA Type 7 Defined for Not-So-Stubby-Areas LSA Type 8 External Attribute LSA for BGP LSA Type 9,10,11 Opaque LSA RFC 5250 back in 2008 discusses these. Cisco, one, it not the largest, vendor which many people are familiar with, only supported 1-5 for the longest but other vendors supported OSPF LSAs (6-11) well before especially with the advent of Traffic Engineering (10-11 "Opaque" LSAs). Very good explanation on the 5 types you discussed here.

@PracticalNetworking 6 ай бұрын

I did say the 5 "main" types of LSAs at the start of this video ;)

@zulfuqarahmad2780 Жыл бұрын

Saying Thank you is a very least. I really have cleared many doubts through your content.

@eternalblue4660 Жыл бұрын

Thanks a ton, very succinct explanation :)

@saidsabar3184 3 ай бұрын

simply amazing

@chantellemorehead9390 2 жыл бұрын

A passed my CCNA yesterday!! Thank you for the videos, they really helped

@PracticalNetworking 2 жыл бұрын

Wohooo! Congratulations Chantelle! Huge achievement =).

@rum3er0 Ай бұрын

great clarification!

@BasitAli-wy2sq 6 ай бұрын

Great explanation ...

@asish4ever 5 ай бұрын

Thank you !

@weedlax6938 2 ай бұрын

Good explanation!

@mikgruff 2 жыл бұрын

Nicely done thank you so much for your time.

@PracticalNetworking 2 жыл бұрын

You're welcome. Glad you enjoyed it =)

@Mr.Acharyya Жыл бұрын

You made a magic in 14 Minute....Great Man

@MuhammadHassan-wv1ns 2 ай бұрын

awesome thanks for explaining

@martinmokran6324 Жыл бұрын

great explanation

@weberleone4295 2 жыл бұрын

Excellent explanation!

@PracticalNetworking 2 жыл бұрын

Glad you enjoyed it, Weber =)

@randyyihsienhan Жыл бұрын

Another great tutorial. Wish to learn advanced BGP and Eigrp from you.

@PracticalNetworking Жыл бұрын

Noted about BGP, Randy. As for EIGRP, I wrote three EIGRP articles you might enjoy: EIGRP Explained : www.practicalnetworking.net/stand-alone/eigrp-terminology/ EIGRP Metric : www.practicalnetworking.net/stand-alone/eigrp-metric/ EIGRP Feasibility Condition: www.practicalnetworking.net/stand-alone/eigrp-feasibility-condition/

@mobcer 4 ай бұрын

finally an explanation that stick to my mind. tnx

@PracticalNetworking 4 ай бұрын

Awesome, glad this helped =)

@avelinojrrealingo5703 Жыл бұрын

Mind Blown!!! its like a clog in my brain has melted due to this OSPF LSA types

@PracticalNetworking 9 ай бұрын

Fantastic! Glad this video helped !

@MT4_Trade_Manager_EA 2 ай бұрын

Thanks so much!

@ShreyA-ms3pe 3 ай бұрын

Wow just wow. These videos helped me to get into one of the MAMAA companies. Thanks to you. Please please make similar videos on BGP.

@PracticalNetworking 3 ай бұрын

Whoa that's awesome! Congratulations! Which one? BGP is on my list, at some point I'd love to get to it. But no imminent plans.

@mehrdadahmadi585 Жыл бұрын

Absolutely amazing

@PracticalNetworking Жыл бұрын

@Apnakitchen.cuisine 3 ай бұрын

So helpfull

@devanandjha5284 2 жыл бұрын

Ed ..Fabulous.. you are my favorite trainer along with jeremy it's lab

@PracticalNetworking 2 жыл бұрын

Thank you, Devanand =). Cheers !

@shahadatanwar4109 2 жыл бұрын

Thanks for easy explanation

@PracticalNetworking 2 жыл бұрын

You're welcome !

@adedejiemmanuel1 2 жыл бұрын

Great explanation.

@PracticalNetworking 2 жыл бұрын

Thank you, Azza.

@ciscobatais2 Жыл бұрын

AMAZING ❤

@amirniko8014 Жыл бұрын

thank you!!

@WDiamhere Жыл бұрын

you awsome man .

@jalalalzamili4486 8 ай бұрын

Well done

@Kaushik846 23 күн бұрын

nice explanation

@James67851 4 ай бұрын

You've mad something quite confusing very understandable. Thank you.

@PracticalNetworking 4 ай бұрын

You're very welcome, James.

@mahendrakumarsahu4395 Ай бұрын

Marvelous ❤❤❤ Brother

@ahmadsalem7222 Жыл бұрын

Just amazin'!

@PracticalNetworking Жыл бұрын

;)

@s_t_8_l_e_s_s 5 ай бұрын

seriously appreciate your videos, wish I had found you before I payed for other courses...

@s_t_8_l_e_s_s 5 ай бұрын

Only a few days away from my CCNA, and your videos have helped explain some topics I was murky on after jeremy & david B's courses. You dont have a Security+ course do you?

@danielandrade671 Жыл бұрын

superb!

@PracticalNetworking Жыл бұрын

Hi Daniel, thank you for supporting the channel =) Glad you enjoyed the video!

@huyvuquang2041 Жыл бұрын

I really really appreciate your work. Keep it up please. You helped me so much....

@PracticalNetworking Жыл бұрын

So glad you found these helpful, Huy. Cheers =) 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_ .

@huyvuquang2041 Жыл бұрын

@@PracticalNetworking Since I use facebook, I will help you share it on this platform :)))

@PracticalNetworking Жыл бұрын

@@huyvuquang2041 Thank you for your support, Huy =)

@hait7393 Жыл бұрын

Thank you for your great work, just one remark regarding type 4/5 LSA, you mentioned that router 6 (which is an ASBR) introduced itself to router 4 by type 1 LSA, assuming that this type 1 LSA will be forwarded by the ABR R2 as a type 3 LSA to other areas, so other areas will know about R6, so there will be no need for Type 4 LSA as a helper for this redistributed type 5 LSA !!

@PracticalNetworking Жыл бұрын

>> assuming that this type 1 LSA will be forwarded by the ABR R2 as a type 3 LSA This isn't entirely correct. The actual Type 1 LSA will not be forwarded. Instead, only specific information from _within_ the Type 1 LSA is forwarded -- specifically _only the IP Subnets contained in the Type 1 LSA are forwarded._ The Routers identity (which is included in Type 1 LSAs) is not included in the Type 3 LSAs. To really understand it, I'd recommend the LSA Deep DIve videos: Type 1 & 2: kzfaq.info/get/bejne/Z6x_dc561KrGc5c.html Type 3: kzfaq.info/get/bejne/bsx2p7hmvJ-7d58.html

@guganobre Жыл бұрын

Thanks for both contributions. I'd like to make a remark about LSA type 5 that originates from an external non-OSPF domain in an NSSA area. Shouldn't it be converted from type 7 to type 5?

@vanbaole8415 5 ай бұрын

Hi Ed I don't get why we need type 4 LSA. When router R6 introduced it self in area 44 via type 1 LSA should the ABR router R2 have sent type 3 LSA including subnet 9.9..9.0/24 in the summary into area 0? so every routers how to reach R6.

@assohonarvar4819 2 жыл бұрын

Thank you

@PracticalNetworking 2 жыл бұрын

You're welcome.

@viveknjoy25 Ай бұрын

Have a doubt at 11th minute of the video about type 4 LSA, R6 will introduce it to R4 by type 1 LSA, and these will be shared to area 0 via R2 as type 3 LSA, so Routers in R1 will knows about R6 right?

@amazingshots1009 Жыл бұрын

Extensive explanation in a brief way 🫶

@thamkinkottayil6375 2 жыл бұрын

Gooooood woooooorrrkkkk👏👏

@PracticalNetworking 2 жыл бұрын

Thank you =)

@user-vx3iw2qh8d 2 жыл бұрын

Hi! I belive, that you missed one important moment about Type 2 LSAs. When you using Ethernet ports on touter (and nowadays you will mostly use Ethernet) routers by default will treat this links as multiaccess, because they can't know do this link connects directly to another router, or there can be switch in beetwen and potentially multiple routers. So, if you only connect two routers by Ethernet link directly to each other - they will treat this link as multiaccess, chose DR and BDR and will send Type 2 LSAs. You need to explicitly configure this links as p2p.

@PracticalNetworking 2 жыл бұрын

Correct! That is explained in the Type 1 & Type 2 deep dive video: kzfaq.info/get/bejne/Z6x_dc561KrGc5c.html =)

@ezawa4 6 ай бұрын

Many thanks. One question about example with 3 Routers R1,R2,R3 starting approx at 2:30, you mention that there's only 1 LSA type 1 per router (and update if necessary). When R3 emits its LSA type 1, in order for R2 to be aware of R3 update, I guess R1 propagates the update with a LSU (?), is it correct ? i am confused for now, with the propagation mechanism in order for all routers in area 0 to have the same LSDB.

@PracticalNetworking 6 ай бұрын

Yes. Correct. After Routers are already neighbors with each other, they just send LSU's with new / updated info when necessary

@dylanwinslow8585 Ай бұрын

Why is R6’s Type 1 LSA / subnet that is sent to R4 not then sent to area 0 / R1 by R2 via a Type 3 LSA (if a type 3 is summarizing all the Type 1&2’s sent within its area) at which point it would know how to reach R6 when trying to get to the external subnet?

@wwolfram33 6 ай бұрын

@ 2:52, if R2 and R3 are then configured with OSPF, would not Hello Packets, DBD, LSR, ... to form adjacency have happen? The forming of the adjacencies must take place with R2 and R3 before L1's can be sent. I can see how LSU/LSAs would be sent upstream from R1, or after adjacencies have already formed. Could you tell me what I am missing? What is the transition from creating full adjacencies between two OSPF routers and when LSA types begin to fully operate. Thanks!

@PracticalNetworking 6 ай бұрын

Yes, all that would still happen. I'm simplifying that out in this video to focus on LSAs. But everything else in the series still applies (hello packets, LSU/LSR/LSA/DBD, neighbor adjacency sequence, and so on)

@narinderpal61 Жыл бұрын

Brill Sir just Brilllllllllllllllllllllllll

@aniswlidi2012 7 ай бұрын

No sure to understand why there is no TYPE 2 LSAs on the 2 segments between R1and R2, and between R1 and R3 since there is also a DR on each link (this after minute 4). Arent these also multi-access links?

@wwolfram33 6 ай бұрын

@10:56, it is stated that R6 has introduced itself into Area-44 using a Type-1 LSA. I am missing something here. Are we assuming that R4 and R6 are already neighbors? If so, how does this introduction happen?

@PracticalNetworking 6 ай бұрын

Yes, they are already neighbors. The implication is that all routers in the same areas have become neighbors because of their Type 1 LSAs. Of course, normally they would be sending hello packets and validating various attributes, but for this video I'm simplifying and saying all routers in the same area are neighbors.

@wwolfram33 6 ай бұрын

Thanks! @@PracticalNetworking

@user-zr3jy1pu1g 5 ай бұрын

Well explained! do you have deep dive in EIGRP?

@PracticalNetworking 5 ай бұрын

I have three articles on my blog that covers most of what most people need to know about EIGRP.

@blackbarry45 Жыл бұрын

gread vid

@PracticalNetworking Жыл бұрын

Thank you =)

@blackbarry45 Жыл бұрын

4:02 can R2 be a DR ? because it just happened in my GNS3 LAB

@PracticalNetworking Жыл бұрын

Yes! If you're building the topology, any of the routers on the multi access segment could be the DR (R2/R7/R8/R9). Itw ill be whichever router wins the DR election (or is the first to be stood up). Details in the DR video: kzfaq.info/get/bejne/g89jp7GEutDGZ2w.html

@sydneym9970 8 ай бұрын

Good explanation. You might have had a typo on you ASBR. Instead of "Boundary" you used "Border"

@exaaltare1170 Жыл бұрын

So if a ASBR router introduces with Type 1 LSA to area 44. Why doesn't that type 1LSA get summerised within Typer 3LSA together with all of the other type 1 and 2 LSA's? Type 4LSA would seem like a owerhead. Im sure im missing some critical detail, can anyone explain?please

@PracticalNetworking 10 ай бұрын

It's not the LSA itself that gets summarized by a Type 3. It's the _content of the LSA_ (in particular, the IP Networks contained in the LSA) that gets summarized by the type 3. Type 3 LSAs do not contain any information about the routers in foreign areas.

@gong2094 Жыл бұрын

❤

@khusi2145 10 ай бұрын

What an explanation ... by the way I'm from India. Could you please tell me the simple definition of a domain ? I'm not getting it.

@buty161 2 жыл бұрын

Do you planning series about EIGRP?

@PracticalNetworking 2 жыл бұрын

Probably not KZfaq videos, but I did write EIGRP articles you might enjoy: EIGRP Explained : www.practicalnetworking.net/stand-alone/eigrp-terminology/ EIGRP Metric : www.practicalnetworking.net/stand-alone/eigrp-metric/ EIGRP Feasibility Condition: www.practicalnetworking.net/stand-alone/eigrp-feasibility-condition/

@zakariabouguenara3728 Жыл бұрын

OSPF's professor

@PracticalNetworking Жыл бұрын

;)

@Martaftw Жыл бұрын

Fcking brilliant explanation. Smthing my lector failed to do so.

@susmitamazumder8390 2 жыл бұрын

Passed the ccna

@PracticalNetworking 2 жыл бұрын

WOHOOO! Congratulations!

@Alestrix76 Жыл бұрын

If you say that the internal routers are representative of any number of internal routers, how about the ABRs? I've watched several intros to OSPF and they all use just a single ABR between areas which immediately makes be wonder about redundancy. I mean isn't this one of the main reasons to use a routing protocol, resilience to hardware (link or router) failures?

@ramend489 Жыл бұрын

@buzooliibrahim8382 Жыл бұрын

I can't say it in the words ❤ Buy the way u forgot to add type 6 & 7 isn't

@rozhyarghx 9 ай бұрын

Type 3 LSA appears to be useless! In your example, if routers from area 55 does not know about router 6, then what was this type 3 LSA that they received?

@Vova67ify 5 ай бұрын

I still don't understand why they created LSA5. They could use LSA1 that ASBR generates anyway to spread external routes. Just put all the external routes that you got via redistribution inside LSA1 and it's done. And you can spread them as normal LSA1. Instead of that they created LSA5 and when they realised that it was unreacheble they also created LSA4. I don't understand. I think I miss something. It looks like for me that they just didn't want to change LSA1. It was simpler to add a couple of more LSAs to handle external routes.