Is it the last post about OSPF?   I hope this is the last main topic post of OSFP, but many functionalities have not been talked about, so OSPF parts should be in the future post like sham-link , opaque LSA and soon on.   Why OSPF authentication is important?   Why should service providers use IGP authentication?   As I mentioned in my other post IGP is one of a most important thing in a service provider life. IGP is the responsible of the backbone IP network control plane. If a bad face guy can access for the SP's infrastructure...    ... And here the post ended, because I have no time to serve my readers....    Life is hard, you have to prioritize your tasks... I would have liked to write these post, but everyday life is more important, than this hobby.   May I will write about my exam preparation... or the next post can be a report about the experience...   At this this time, that's all folks...        

 OSPF again  Why OSPF is such important? Why do I care for this topic so much time?   Interesting questions, I do not really know. When I start to process a topic for my exam preparation I do not know how much time I have to learn it. But when I learn it, I feel the importance of the subject area.     If you would like to read more detailed information about OSPF I suggest that link: https://www.ciscopress.com/articles/article.asp?p=2294214&seqNum=4   So let me explain to you that what are the differences between OSPFv2 and OSPFv3? In a high level view the two protocols are only different in the Internet Protocol version support. OSPFv2 is only support IPv4. OSPFv3 support both AFs (address family), but If you wanna know some detail about the other differences you need research better this topic. 1. Network types In OSPFv2 there is 5 network type which is the same in OSPFv3 broadcast non broadcast point-to-point point-to-multipoint point-to-multipoint ...

Hello there! I can not leave the OSPF subject because  it is too beautiful to abandon it. In this post I try to demonstrate how the LSAs work in different OSPF scenarios. In the last post I wrote what is the LSAs, which network type is available, and which router types are exist in an OSPF network. But I do not described these things. On this post I try to define these topics better.  To understand that LSAs how can be flooded on different areas you need to understand the area types. As I mentioned before, there is 5 type of area exist of OSPF. Basically in a backbone/regular area the following LSA types will be flooded: Type 1 Router LSA Type 2 Network LSA Type 3 ABR Summary LSA - if ABR exist in the area. Type 4 ASBR Network LSA - if ASBR exist in the area. Type 5 ASBR Summary LSA - if ASBR exist in the area.  Backbone area is special, because it is responsible for the other area can be connected each other. And what about stub area? Stub types of areas help us to redu...