# OSPF LSA Types Explained **URL:** \ **Category:** Lessons Discussion\ **Created:** [December 27, 2016, 4:09pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127 "2016-12-27T16:09:56Z")\ **Posts on this page:** 20\ **Page:** 2
**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:** [June 25, 2015, 1:22pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/21 "2015-06-25T13:22:20Z")
No problem 🙂 I’m working on the website today and had Visio open… ---
**Author:** ![soufiane.adil](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/s/3d9bf3/32.png) [@soufiane.adil](https://forum.networklessons.com/u/soufiane.adil)\ **Post date:** [July 13, 2015, 7:35pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/22 "2015-07-13T19:35:55Z")
Good job Rene, i like your explanations. keep going. Soufiane ---
**Author:** ![danishqadri79](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/d/7ea924/32.png) [@danishqadri79](https://forum.networklessons.com/u/danishqadri79)\ **Post date:** [August 11, 2015, 1:15am UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/23 "2015-08-11T01:15:06Z")
Hi Rene just a little confused you did not advertise 2.2.2.2 network in R2 so how come it got populated in ospf database table ? and one more question using redistribute command makes a router an ASBR?? whats the difference between advertising a network with network command or using a redistribute command ? Many Thanks ---
**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:** [August 11, 2015, 11:06am UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/24 "2015-08-11T11:06:19Z")
Hi Muhammed, R2 has selected 2.2.2.2 as the router ID for OSPF, that’s why you see it in the database: > **[OSPF Router ID](https://networklessons.com/ospf/ospf-router-id)** > > Each OSPF router selects a unique router ID. This lesson explains how the router ID is selected. Redistribution is normally used to import/export prefixes between two routing protocols, for example OSPF and EIGRP. When you configure redistribution on OSPF then it becomes an ASBR (Autonomous System Border Router). Here’s an introduction to redistribution: > **[Introduction to Redistribution](https://networklessons.com/ip-routing/introduction-to-redistribution)** > > Redistribution is used to import/export information between routing protocols. This lesson describes the basics of redistribution. Rene ---
**Author:** ![akashmahajan](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/a/d78d45/32.png) [@akashmahajan](https://forum.networklessons.com/u/akashmahajan)\ **Post date:** [September 4, 2015, 5:41pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/25 "2015-09-04T17:41:44Z")
Hi Rene, If the ASBR is in a different area and set the FA to non-zero ( if all condition satisfy for non-zero FA.. of course), then does routers in other area use Type4 LSA to recurse Type5 LSAs? or it will use type 3 LSA for FA address to recurse type5 .in other words in this scenario does type 4 LSA is ever looked at? ---
**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:** [September 6, 2015, 11:21pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/26 "2015-09-06T23:21:57Z")
Hi Akash, Good question, I think as long as there is a forward address then the router will prefer this instead of using LSA type 4 to lookup the ASBR. Even if the ASBR is in another area. I’d have to lab it up to be sure though. Rene ---
**Author:** ![adapa.ajith](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/a/e79b87/32.png) [@adapa.ajith](https://forum.networklessons.com/u/adapa.ajith)\ **Post date:** [September 9, 2015, 6:10am UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/28 "2015-09-09T06:10:09Z")
R1#show ip ospf database Router id is 1.1.1.1but not 11.11.11.11 ---
**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:** [September 11, 2015, 4:59pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/29 "2015-09-11T16:59:03Z")
Hi Ajith, Do you mean in the first example? This happened because I already had a second loopback interface with 11.11.11.11, that’s why this became the router ID. Maybe I should change this, I can imagine it could be confusing. Rene ---
**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:** [September 11, 2015, 5:05pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/30 "2015-09-11T17:05:19Z")
LSA type 8 and 9 are for IPv6 OSPFv3, I’ll cover these in a different lesson. LSA type 10 is used for traffic engineering but I doubt that it’s implemented on Cisco IOS. ---
**Author:** ![edgardh](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/e/5f9b8f/32.png) [@edgardh](https://forum.networklessons.com/u/edgardh)\ **Post date:** [December 5, 2015, 1:36pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/31 "2015-12-05T13:36:01Z")
Hi Rene, Following the first “show ip ospf database” we can see 11.11.11.11 while not yet configured. This could be misleading for many. Thanks for the great content! Eddi ---
**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 13, 2015, 10:16am UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/32 "2015-12-13T10:16:31Z")
Hi Eddi, I agree, I just fixed it so it shows the correct router ID. Rene ---
**Author:** ![suneethabdullah](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/s/f17d59/32.png) [@suneethabdullah](https://forum.networklessons.com/u/suneethabdullah)\ **Post date:** [December 17, 2015, 5:45pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/33 "2015-12-17T17:45:37Z")
Hi Rene, Why is show ip ospf database output Type-5 AS External Link States are shown without assigning any area? also if type 5 external routes are in one area then Type-4 LSA will not be present as the same is not necessary to decode the router ID. or just by seeing the absence of Type-4 LSA can we conclude that an area is stub?.. please help very confused. ---
**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 18, 2015, 1:07pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/34 "2015-12-18T13:07:57Z")
Hi Suneeth, We don’t require area numbers to get to the prefix that the LSA type 5 is advertising. The only thing we need is to know is how to get there, which is advertised with LSA type 4. The absence of LSA type 4/5 only means there is no ASBR, which can also occur if you use regular areas and don’t use redistribution. Rene   ---
**Author:** ![kamawal0008](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/k/e480ec/32.png) [@kamawal0008](https://forum.networklessons.com/u/kamawal0008)\ **Post date:** [January 6, 2016, 11:10pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/35 "2016-01-06T23:10:59Z")
Hi, Rene, Do we have a distinct DR/DBR per area? or we would have only one DR/DBR for the the whole OSPF X? Regards ---
**Author:** ![suneethabdullah](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/s/f17d59/32.png) [@suneethabdullah](https://forum.networklessons.com/u/suneethabdullah)\ **Post date:** [January 7, 2016, 10:16am UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/36 "2016-01-07T10:16:55Z")
DR/BDR is elected per multiaccess segment. So you can have different dr and bdr in same ospf router if the router have different ethernet connections (same.subnet is not.allowed on router) ---
**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 7, 2016, 1:07pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/37 "2016-01-07T13:07:27Z")
Hi Adil, Like Suneeth explained, the DR/BDR election is done per multi-access segment. Not per area or OSPF domain. Rene ---
**Author:** ![kamawal0008](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/k/e480ec/32.png) [@kamawal0008](https://forum.networklessons.com/u/kamawal0008)\ **Post date:** [January 8, 2016, 2:48am UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/38 "2016-01-08T02:48:05Z")
Thank you.. Rene and Suneeth! Would you please explain it a little more! I heard in a video Rene’s saying " Multi access means the ability to access each other mutually. However i don’t know what are the rules for multi access. I mean can you give an example of some networks, multi access and not multi access segments? ---
**Author:** ![shantel](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/shantel/32/360_2.png) [@shantel](https://forum.networklessons.com/u/shantel)\ **Post date:** [December 27, 2016, 4:10pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/39 "2016-12-27T16:10:39Z")
19 posts were merged into an existing topic: [OSPF LSA Types Explained](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127) ---
**Author:** ![suneethabdullah](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/s/f17d59/32.png) [@suneethabdullah](https://forum.networklessons.com/u/suneethabdullah)\ **Post date:** [January 8, 2016, 7:55am UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/40 "2016-01-08T07:55:01Z")
Multi Access - Ethernet, frame relay Non Multi access - Point to point serial links ---
**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 8, 2016, 12:48pm UTC](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127/41 "2016-01-08T12:48:48Z")
The best example of multi-access is indeed Ethernet, all devices on the same segment are able to reach each other directly unlike a point-to-point link where there is only one other device on the other end.   [Previous page](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127.md?page=1) [Next page](https://forum.networklessons.com/t/ospf-lsa-types-explained/1127.md?page=3)