OSPF Area Types - Stub, NSSA, Totally Stub, Totally NSSA - Practical OSPF
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- čas přidán 24. 07. 2024
- By default, every OSPF area starts as a "Normal" area. Inside a Normal area, every type of LSA / Route is allowed. But OSPF also has the ability to designate areas as Stub, or Not-So-Stubby-Areas (NSSA) which allows an OSPF engineer to optimize the types of Routes and LSAs which exist inside an Area.
In this video, we explore the five OSPF area types (Stub, Totally Stubby, NSSA, Totally NSSA). We also introduce the concept of a Type 7 LSA, and how they are used within Not So Stubby Areas and translated by ABRs which border an NSSA.
This is lesson 14 of the Practical OSPF series. The full series is available here:
• Practical OSPF
00:00 - Intro
00:24 - Pre-Requisites: Understanding OSPF LSAs
00:56 - Topology Introduction & LSA Illustration
02:56 - Normal Areas
03:38 - Stub Area (Stubby Area)
06:08 - Totally Stub Area (Totally Stubby Area)
08:08 - NSSA - Not So Stubby Area
09:49 - Type 7 LSA instead of TYpe 5 LSA in NSSA
11:10 - Type 7 LSAs are translated into Type 5 LSAs
12:08 - The problem with NSSA Areas
13:38 - Yes, I just said Not So Stubby Area Areas
13:55 - Totally NSSA / Totally Not So Stubby Area
15:45 - 5 OSPF Area Types or 3
19:21 - Summary / Outro / Next Lesson
=== PRE-REQUISITES ===
LSAs and LSDBs:
• OSPF LSA - the BEST ex...
Designated Routers and Backup Designated Routers (DR / BDR):
• Designated Router // B...
OSPF Hello Packets:
• OSPF Hello Packets :: ...
================
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Totally!
@@parheliaa ;)
Probably the best video on OSPF areas.
Dear Mr. Harmoush, you're truly a master in this profession. You're sincerely a teacher, and you indeed "have a passion for teaching complicated topics in simple, approachable language." Thank you.
Thank you for the kind words, Azza =)
Thanks for incredible teaching 😊
Great teacher, love your diagrams and how much effort you put into teaching to make something so simple. Thank you!
This video is the best! What a banger covering these topics. Keep it up bro
Absolutely perfect explanations, as always. And just the topic I needed at the moment. Thank you, Ed!
Glad there was good timing =). Cheers, Zvonimir!
Again, so far, Mr. Harmoush, you're the best teacher and master in this field, you are really passionate about teaching, you cover entierly the topics and simplify them in such an easy way, and the illustrations are of high quality. Thank you so much for what you're doing and hope to see more content !
Excellent explanation and clearly presented. Thank you for speaking at a normal pace and the content your providing.
Glad to hear from you clarification on OSPF area type
Great explanation. Thank you for the hard work!
Awesome explanation …I was struggling to get these concept for last 2 -3 years .
Glad it finally clicked =)
The best video on area types!
Thank you, Bill. =)
Great video. I love watching your content
Oh boy! :) being ccnp for 10 years and sometimes need to refresh some stuff i dont work with. Anyway, your ospf videos are the best i have ever seen :) many thanks from Prague
Informative. I am getting addicted to it.
Awesome =)
Amazing work, you helped me a lot
excellent presentation of complicated OSPF area types.
Great lesson! Thank you
This is Awesome!
Awesome videos, Thanks ED!
You're welcome, Nasir =)
Love from India, waiting for your content ☺️
Yes, I'm also
Cheers, from Seattle =). Hope you enjoyed the video!
Cheers! =)
Thank you very much for this explanation.
wonderful video sir Eddie! I am new to this field yet you made it easy for me to learn, I was about to stop pursuing this field (because it was hard to follow through the books and videos) but you brought this passion back to life.
Thrilled to hear that =)
Best ccna content on youtube 👏
It was a very nice and understandable tutorial.Thank You
Excellent video.
Thank you, WIllie =)
Very good video, thank you so much! It helped a lot
I really enjoyed your video, it was very clear and helpful. You have a great way of explaining things and making them easy to understand. I would love to see more videos from you, especially on BGP. That's a topic I'm very interested in and I think you could teach it well. Thanks for sharing your knowledge and skills with us.
Noted, thank you for being a supporter of the channel. I would love to publish some of my BGP related content on the channel.
Thank you for your detailed videos ☺️
You're very welcome. Cheers, Ratheesh!
Thanks for the great explanation 👍🏾
You're very welcome, WemDizzle =)
Finally I have understood these confusing ospf area types after watching this video, thank you.
You're very welcome, Randy. =). It's been neat seeing your comments on these videos =)
@@PracticalNetworking I have read several network CBT from INE, IPTV Pro, CBT Nugget, Udemy for CCNP approach. I really think your videos are on the top of quality and your unique analysis to explain the theory is the best among them. You deserve to set a paid platform to charge a fair fee for the advanced program on this quality and effort.
@@randyyihsienhan Thank you for the very kind words Randy. I'm looking to start doing more in the online course space, so look out for that soon. I already have a few courses published here: classes.pracnet.net/
Thank you Ed for clear explanations , love from India
Cheers, L. Glad you enjoyed it =)
Loved it, Great Explanation!! Request you to complete Network Fundamental Series. Thank you Ed!!
Cheers, Amit =). Noted =)
It would be cool if you do the same course but for EIGRP and for BGP as well . Best networking professor by far
Glad you're enjoying these, Rocio. I do have some EIGRP content published:
Understanding EIGRP - 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/
@@PracticalNetworking what about IS-IS ? i'd love IS-IS course in the same didact way you've done this OSPF course.
awesome
Love you bro
master at work . This is the one i was most confused about , well explained
Glad you enjoyed it Don. =) Cheers !
@@PracticalNetworking Just a quick question though , ED. If Totally stub Area doesn't allow type 3 LSA's , why does it allow one to be injected to give the default route? (assuming i have understood correctly of course)
@@Don-Carillo That default route Type 3 is the exception. It's the only TYpe 3 allowed in a "totally stub" area. If that didn't exist, none of the routers in the stub area would have any routes to _any_ subnet elsewhere in OSPF.
@@PracticalNetworking makes sense. Thank you
@@Don-Carillo Cheers, Don =)
😊 THANK YOU SOO MUCH
Cheers, Kimo. Glad you enjoyed it.
Hi, great graphics, may i know which software or application was it prepared on?
Thnks
Out of curiosity; What sort of case by case approaches are you referring to regarding getting type 5 routes from another area (area 22) into the NSSA? I’m referring to a scenario where no default route is injected.
Are we talking simply using static routing instead or is there some sort of OSPF trickery that can be done ?
Amazing content, as always!!
Thank you very much Ed... Very clear explanation... Can you please also cover the route aggregation, redistribution and filtering topics in OSPF. Really appreciate. Thank you!!!
Those are on the list! Glad you've enjoyed these, Geetha.
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_ .
Fantastic explanation, I hope you do the same for BGP someday.
Eventually, I will. Glad you enjoyed it! Thank you for supporting the channel!
I have a question; in a previous video you mention that type 5 LSA are forwarded by ABRs only.
Assuming area 0 links are P2P, how do the Type 5 LSAs in this video reach Area 33?
If I understand correctly, they are first forwarded by R2 and R4 from Area 22 and Area 44 respectively into Area 0.
From here, how do they reach Router 3 for them to be forwarded to Area 33?
They can't be forwarded by R1, can they?
Thanks for the lessons!
Best explanation!!..Can you do some videos for L2 Protocols? ie. Spanning Tree???
Kindly make videos on EIGRP and BGP in the same fashion like segregating concepts and deep dives so that it would be clear to understand.
How can i access the deep dive videos?
Another superb lesson. thank you. I'm just checking out your website also. Allot of good content on there. Might even get my wallet out :)
Pls differentiates the E1 and E2 routes in ospf
Sir, if area 44 NSSA doesn't allow type 4 LSA how routers of other area going to know about ASBR location (Earlier we learned about ASBR summary LSA )
I feel a bit confused here:
Are these AREA types the same as the LINK type of a link advertised in an LSA? in other words, is a stub AREA the same as a STUB link/network?
What if R6 didn't exist, R3 had a stub link/network instead, and was also part of Area 0? would that mean that R3 had a stub network/link inside a normal (non-stub) area?
How does a router know what type of area that is? is it specifically configured or automatically determined?
How does the LINK (stub, transit, etc.) and AREA types (stub, NSSA, etc) correlate to the NETWORK (broadcast/point-to-point, etc) type?
Good question. No, the _Link types_ are different than the _Area Types_ and different from _Network Types_ . There is some overlap, but for learning I think it's best to understand each of these as completely separate independent topics. It's unfortunate OSPF used such similar terminology for each, it leads to confusion. The video on this series on Type 1 & 2 LSAs will go into more detail about Link types.
@Practical Networking: what is the benefit of changing an area to NSSA when type 7 lsa will be translated to type 5 lsa... why not keep it a regular area?
Because it spares the NSSA from having to maintain the Type 5 LSAs from _other_ areas (i.e., the 100 Type 5 LSAs redistributed from R5)
@@PracticalNetworking Thank you.
@@wizix9877 You're welcome
Ed, I don’t get the point. If that needs to achieved ABR of Area 44 should inject the Default route using Type 3 LSA for to reach other areas. With Type 5, I have 100 routes and with Type 7 also, I have the same 100 routes. Why can’t just have Type 5 and inject a default route to reach other areas. I am confused by the usage of Type 7 LSA.
Why NSSA Area ABR not send default route explicitly inside NSSA area? any reason ?
A stub area, by definition, has only one way out. So it is safe to assume a default route should point to the ABR.
In an NSSA area, there can be two ways out (the ABR, or the Redistribution Router). Therefore, OSPF can not assume where to point the default route, so doesn't inject one by default -- leaving the administrator to define where the route should point.
@@PracticalNetworking Thank you!! how about Totally NSSA?
@@amitpatil1900 "Totally" NSSA is a Cisco implementation, you'd have to ask them why they chose to include a default route by default. I assume it's because without it, you'd lose access to all the networks you would have learned about from the Type 3 LSAs (which are removed in a Totally NSSA area).
@@PracticalNetworking Thank you!! I understand that, just want to confirm is there any reason behind that.
14:01 Michael Scott screaming No God No, Please no !
LSA type
Type 1 LSA: Router identifies itself and it's links
- IP Networks/ Subnet Masks Costs for each Router Link
- Used to build typology map of local area
Type 2 Network LSA: Sent by Designated Router (DR)
- When multiple routers connected to the same multi-access link
Type 3 Summary LSA: Contain IP Networks from foreign areas
- Sent by ABR in both directions
- Summaries Type 1, Type 2 and Type 3 LSAs
Type 4 ASBR Summary LSA: Instructions to reach ASBRs
- Send by ASBR
Type 5 External LSA Contain an IP Subnet redistributed into OSPF
- sent by ASBR
- Forwarded unchanged throughout OSPF domain