135.137.154.1xxxxxxx
255.255.255.10000000 (AND)
----------------------
135.137.154.10000000
135.137.154.128 --> network id
broadcast? 135.137.154.255
135.137.154.256 (next)
135.137.155.0

16+12=28
H=32-28=4
2^4=16
48-63
49-62

35
1 2 4 8 16 32 64 128 256
32<35<64=2^6
H=6 N=32-6=26
/26 --> 255.255.255.192

Chap 7 summary
1. Ethernet frame format
2. shared media
3. token control media
4. point to point
5. ring

Chap 8 supplement
Thicknet 10Base5   500m/section  max 2500m
Thinnet  10Base2   185m/section  max 925m