Concept of External Routes in OSPF | OSPF-BGP-MPLS From Scratch !!! | Concept Video-8

This video talks about how to introduce external domain routes in to OSPF. We have covered following questions and concepts in this video,
1. What is E1 and E2 routes? Why do we need have E1 and E2 routes is OSPF?
2. What should be the seed metric while redistributing external route ?
3. How to redistribute RIP routes in to OSP?
4. Does router run SPF algorithm when they receive any external routes?
5. What are Type-4 and Type-5 LSA's ?

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[jsboy]

Another missing point point is that for summary roters i.e for inter area and outside domain routes the cost/metric behaviour is like Distance vector protocol and not as a LINK stateprotocol, stating this will make it easier for people to understand the metric for type-3/type4 and type 5 LSAs

[jsboy]

why will R3 inform of the ASBR information, supposedly R4 is the DR, and also an ABR. isn't the ASBR supposed to share it's information to the DR/BDR. I am assuming that this is a multi-access network, now within the area if the ASBr will have full adjacency with the DR(R4) in this case. R4 is also the an ABR and DR, so which of the two ABRs will generate the Type 4 LSA. Suppose both of them (R3 and R4 are ABRs) and R4 is Dr and the reachability via link cost within the area is same, which routers LSA will be flooded as type 4 LSA in the OSPF domain @bridgewhy

[jsboy]

Type 4 is generated by ABR because ASBR sends a type 1 LSA with special bit set in the options filed which announce about it being a ASBR. Once this is flooded then only ABR knows that an ASBR is present. Now this leads back to my original question, since this is amulti-access network and R4 is the DR and an ABR why will R3 which suppose is not the BDR get the type 1 LSA from R6, R6 will share it's LSA to R4 and then R4 will flood it in the area. Now both R3 and R4 are ABR, R8 will flood the LSA of the ABR which has better cost or will it install both. It is very clear that if R3 is not a BDR, it cannot get the ASBR information from the R6 directly, I think you have skipped over this part

[jsboy]

I don't think that R3 will be able to flood the information about the ASBR to area 2 route, Area 2 is a different Area and the flooding domain for R3 is area 0 and area 1. It will inform to R8 and R8 will be sending the ASBR information to other routers in area 2. How do you think R3 can flood the type 4 LSA to area 2 as it has no interfaces in area 2 @bridgewhy