OSPF Update Process

---

OSPF has two different types of updates
        1. Intra-Area
        2. Inter-Area
Intra-Area: When we talk about the update process in the same area, OSPF basically floods the complete database to all the routers present in that area and this is the behavior of Link-State behavior

In this case, let's suppose R1 is already advertising the first 4 addresses to the domain and when we will add one more network 1.1.1.5/32 in OSPF it will regenerate the complete database again including previous prefixes and will share to complete domain
This is how Intra-Area update works
Inter-Area: Now in case of an update process in another area, OSPF just shares the new changes to another area, and it is like an incremental update just like distance vector protocol(EIGRP: uses incremental update, only announce new changes to router) same here router announces only new changes in another area

In this topology, we have 2 different Area, Area 0 and Area 10
So now R2 will act as ABR(Area Border Router) (in future we will discuss more about ABR concept)* so now here assume R1 is advertising only the first 4 prefixes to R2 and R2 will advertise the same to Area-0, now let us advertise 1.1.1.5/32 prefix on R1
So here R1 will first advertise the complete database again to R2 as it is the part of the same area and can say Intra Area, now R2 will get the same update but it will just reflect 1.1.1.5/32 updates to Area-0, it will not send all the received update from Area-10
This is how the Inter-Area update process works