CISCO CCNA OSPF

Posted filed under Cisco CCNA.

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.

 

Receive our Cisco CCNA Packet Tracer!
Get our complete tutorial in PDF

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

 

  Method #2 )

sometimes they give you WILD cards and you have to understand what it covers

 

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

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-77o50-discount-on-self-study-online-class

Want more information on how to become Cisco CCNA Certified? Learn more!
Join our Cisco CCNA facebook study group!


Also published on Medium.

Comments are closed.