I thought I mastered binary that I could even solve them by looking at it. How
wrong! Personally I had no problems with binary maths and every time I saw it
on my CCNA or CCNP exam I knew that they are my soft points. It seems the way
the instructor does binary tricks me somehow and I happen not to follow.
For example, I don’t understand why he would break 7 contiguous subnets into
three or more options when summarising them? Let’s take 172.16.31.0 –
172.16.37.0 subnets. My understanding is that you convert all to binary and
look at the pattern ( common bits) and then come up with summary address. Since
the 1st two octets are similar, we should concentrate on the third octet.
128 64 32 16
8 4 2 1
172.16.31.0 0 0 0 1 1
1 1 1
172.16.32.0 0 0 1 0 0
0 0 0
172.16.33.0 0 0 1 0 0
0 0 1
172.16.34.0 0 0 1 0 0
0 1 0
172.16.35.0 0 0 1 0 0
0 1 1
172.16.36.0 0 0 1 0 0
1 0 0
172.16.37.0 0 0 1 0 0
1 0 1
Summary 172.16.0.0 /18?
Hope to hear from you all.
Regards,
Horongo
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