21. Binary Introduction (4:11)

Why do we need to know binary?
- Subnetting
- Access Lists - when you want to permit or deny traffic based on IP address
- etc…
A binary digit is called a bit.
There are two possible states in a bit, usually expressed as 0 and 1.
- Binary = 0 & 1

22. Binary Math

2 states = ON or OFF

4 Cables

16 Different combinations are possible.

2022-07-03^7=128$
2022-07-03^6=64$
2022-07-03^5=32$
2022-07-03^4 = 16$
2022-07-03^3=8$
2022-07-03^2=4$
2022-07-03^1=2$
2022-07-03^0=1$

0000 0001 = 1 in decimal

1100 0000 = 192 in decimal

1111 1101 = 253 in decimal

1111 1111 = 255 in decimal

Substraction method (decimal to binary):
132 = 132-128(1)-4(1) = 10000100

Divide method:
e.g. 132
132/2 = 66 (0)
66/2 = 33 (0)
33/2 = 16.5 (1)
16/2 = 8 (0)
8/2 = 4 (0)
4/2 = 2 (0)
2/2 = 1 (0)
1/2 = 0.5 (1)

And then Answer is from Bottom to Top: 13 = 1000 0100 in binary

IP Address = 4 octets / 32 bit
1 octet = 8 binary values = 8 bits

10.129.16.123 = 0000 1010.1000 0001.0001 0000.0111 1011

223=11011111
249=11111001
253=11111101
128=10000000
11000001=128+64+1=193
11101101=128+64+32+8+4+1=192+45=237

Why do we need to know binary? #card

Binary is part of subnetting masks, IP addressing, Access Lists.
Thus if you want to configure network and know what is going on. ou then need to know binary.
IP addresses consist of 32 binary values, or in other words 32bits. Which are separated into 4 different octets. 1 octet = 8 bits/ 8 binary values

What is the binary equivalent of decimal 255? #card

What is the binary equivalent of decimal 128? #card

What is the decimal equivalent of 11000001? #card