Cisco CCNA OSPF and Wild Card Part 1
Wild cards are very important in OSPF
There is two ways to represent wild cards:
Method #1)
suppose you have /30
Do as follow:
255.255.255.255-
255.255.255.252
0. 0. 0. 3 this is my wild cards
Another ex:
/29
255.255.255.255-
255.255.255.248
0 .0. 0. 7 this is my wild cards
Another ex:
/28
255.255.255.255-
255.255.255.240
0. 0.0.15 this is my wild cards
Another ex:
/24
255.255.255.255
255.255.255.0
0 . 0. 0. 255 this is my wild cards
Hint: When you advertise your OSPF you need to use subnet ID with correct WILD cards.
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for example
if I have R1 connected to R2
R1 =10.10.10.9 /30
R2 = 10.10.10.10 / 30
My subnet ID=10.10.10.8
R1#config t
router ospf 110
network 10.10.10.8 0.0.0.3 area 0
subnet ID wild cards
If you want to Advertise on R2#
R2#config t
router ospf 110
network 10.10.10.8 0.0.0.3 area 0
[bs_icon name=”glyphicon glyphicon-chevron-right”] [bs_icon name=”glyphicon glyphicon-chevron-right”] Method #2 )
sometimes they give you WILD cards and you have to understand what it covers
[bs_icon name=”glyphicon glyphicon-chevron-right”] hint : Always always the wild cards is one number less than BLOCK size
so If I say
network 10.10.10.0 0.0.0.3 that means I am advertising block size of 4
10.10.10.0
.1
.2
.3 so i am advertising a block size of 4
If I have Network 10.10.10.0 0.0.0.7 area 0
that means I am advertising block of 8
that is I am including 10.10.10.0
.1 ,.2 .3 .4 .5 .6 .7
[bs_icon name=”glyphicon glyphicon-expand”] Watch the video and you will be able to understand OSPF and Wild Card Part 1 much better and Please subscribe to our YouTube Channel.
https://www.youtube.com/watch?v=fw5-2vD-77o
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Also published on Medium.