By
referring to EE Tech News volume 9 December 2015 in page 3 or the link http://eetechnews.blogspot.com/2015/11/ipv4-subnetting.html, the revised version of the rules of
borrowing bits from host portion to create subnet ID is between 1 bit to the
maximum host bit. It means that if we borrow the host portion in Class A, the
maximum bit is 24 bit while class B and C are 16 and 8 bit respectively. If the
maximum host portion is borrowed to create subnetting, there is no host at all.
The revised version is implemented in order to fully utilise the IPv4.
IPv4
size is 32-bit and it is represented as X.X.X.X which X comprises 8-bit (1
octet). In Cisco examinations, you are not allowed to use the calculator. Thus,
it is important for you to remember the value of each of the binary-to-decimal
conversion and the IPv4 classes. Table 1 shows the value that you should
remember. Table 2 shows the usage of IPv4 including the reserved IP address. Multicast IP address such as 224.0.0.5 is used for server OSPF for the Whatsapp Group. Class E IPv4 is for research purposes which mostly used by USA universities.
Table 1
Binary
in 1 octet
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
27
|
26
|
25
|
24
|
23
|
22
|
21
|
20
|
|
128
|
64
|
32
|
16
|
8
|
4
|
2
|
1
|
|
IPv4
classes
|
A
00000000
01111111
|
B
10000000
10111111
|
C
11000000
11011111
|
D
11100000
11101111
|
E
11110000
11111111
|
|||
First
octec for final classes
|
128
|
192
|
224
|
240
|
248
|
252
|
254
|
255
|
Range
of Use
|
1-126
|
128-191
|
192-223
|
224-239
|
||||
Table 2
A
|
B
|
C
|
D
|
E
|
1.0.0.0
=> 126.255.255.255
|
128.0.0.0
=> 191.255.255.255
|
192.0.0.0
=> 223.255.255.255
|
224.0.0.0
=> 239.255.255.255
|
240.0.0.0
=> 254.255.255.255
|
Internet
|
Multicast
|
Research
purposes
|
||
10.0.0.0
=>10.255.255.255
|
172.16.0.0
=> 172.31.255.255
|
192.168.0.0
=> 192.168.255.255
|
||
Private
addressing
|
||||
Reserve IP Address
|
||||
127.0.0.0
=> 127.255.255.255
|
||||
Reserve
for loopback testing
|
||||
0.0.0.0
=> 0.255.255.255
|
||||
Default
route and wildcart mask
|
||||
169.24.0.0
=> 169.254.255.255
|
||||
APIPA
Automated Private IP Address
|
||||
255.0.0.0
=> 255.255.255.255
|
||||
Broadcast
and Subnet mask
|
||||
Written
by Siti Sara Rais
Source: CCNAx training materials at UiTMCTKD on 8 August 2016 - 12 August 2016.
Source: CCNAx training materials at UiTMCTKD on 8 August 2016 - 12 August 2016.
