Re: OSPF Area0 Vs Non-Zero Area [ Anyone Please ]

Hi Bilal,

the questions is, Why all the areas must be connected to Area 0, and what
happens if you lose the connectivity to area 0?
Basically, I recommend to you think about, how do you think ospf avoid
routing loops when dijkstra's algoritm is calculating the shortest path?
How other dynamics routing protocols as RIP or BGP do it? Maybe
Split-Horitzon?

So the answer to your q|estions:
OSFP, don't use the shortest path from "R6" to "R1" thru area 1 because
doing that you can loop the network. The mechanism that OSPF has is use area
0 as a central point. So you are nearest of farest from area 0 non nearest
or farest from device A to B.
If you add the cost from router 6 to area 0 and later you add the cost from
router 1 to area 0, and inside the area 0 to the DR if you have it, then you
will have "total cost".

You need to add your own cost, because the cost is calculate it, from router
6 to the DR(itself) PLUS the other router R1 to the DR. At this last point
is when you are adding your own cost, because the total cost is from area 0
and to area 0. Non from router 6 to router 1.

HTH,
Robclav

--
Robert Clavero
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