Common Count: decimal number 1010D, binary 1010B, 1010H hex
Computer system Number:
Number = Composition made on each digital value of the bit a *
IPV4 address a total of 32bit
way people use the decimal point to remember
A total of 128bit IPv6 address
the main purpose of the study is to calculate the binary IP address
The best binary decimal system conversion method using eight thousand four hundred twenty-one
2 ^ 72 ^ 62 ^ 52 ^ 42 ^ 32 ^ 22 ^ 12 ^ 0
128 64 32 16 42. 8. 1
Examples: The grab into decimal 11011011
methods: adder
128 + 64 + 16 + 8 + 2 + 1 = 219
Method two: subtractor
11111111 = 255
100000000-1 = 255
255-32-4 = 219
Summary: Decimal Binary conversion, see more than 0 or more than 1, if more than 0, with the addition; if more than one, subtraction
Decimal Binary transfer
155-128 = 27-16 = 11-8 = 3-2 = 1
10,011,011
0000 0 0001 1 0010 2 0011 3 0100 4 0101 5 0110 6 0111 7
1000 8 1001 9 1010 A 1011 B 1100 C 1101 D 1110 E 1111 F
4 = one binary hex
example: AOH 10100000B EFH 11101111B A3DH 101000101101B
Example: 1,011,011,011,000,011 and 11,011,011,000,011 convert a hexadecimal
1011 0110 1100 0011 B6C3 0011 0110 1100 0011 36C3
IPv4 Address:
host unique identifier, to ensure normal communication between hosts
A network coding, a network node to determine the
IP address consists of 32-bit binary composition
IP address consists of two parts
the network bits
identify the address range in which the
host bits
identify the address of the id
can calculate the number of bits of the host IP-2 segment, the number of hosts 2 -2-bit host
Subnet Mask: is continuous 0 to 1 and continuous composition, a continuous length of prefix is 1, used to represent
Determine whether the IP address belongs to the same network segment, see the network bits
Address class
A: 1-126 NetMark prefix 255.0.0.0:. 8
B: 126-191 NetMark prefix 255.255.0.0: 16
C: 192-223 NetMark 255.255.255.0 prefix: 24
D: 224-239 multicast, broadcast video, game open black, p2p download
E: 240-255 research
Special:
127, local loop
169, can not automatically obtain ip
Private address:
A: 10.0.0.0-10.255.255.255
B: 172.16.0.0-172.16.31.255
C: 192.168.0.0-192.168.255.255
Questions: 192.168.10.20/24,192.168.10.10/16,192.168.20.10/24 able to communicate?
1 and 2 can communicate with the incommunicable 23
Conclusion: host communication, in accordance with the first mask on the longest match is determined whether the same network segment
Classless address:
192.168.1.1/30
network bits: 30
Host Bit: 2
a total of four ip, available 2
192.168.1.0 ~ 192.168.1.3
192.168.1.1 1.2
192.168.1.10/25
network bits: 25
Host Bit: 7
a total of 7 th = 128 IP 2 of
0 ~ 127
Subnetting:
Why:
save IP address
planning IP address, to facilitate aggregation, reduce routing entries in core routers
subnetting If the private network, there is no sense
of what is subnetting
VLSM: Variable Length Subnet
by changing the mask length of network planning
How divided
1. The 24 bit segment network host 8
Total ip 2. The segment 2 ^ 8 = 256, the address range 0-255
3. The segment of the range of available addresses 1 to 254.
The company has four sectors and number four departments are 100,30,10,4 require the use of a network segment 192.168.1.0/24 this plan
with the binary value of the properties, the number of ip addresses only 1,2,4,8,16 , 32,64,128
calculate the number of sectors required for each IP
1.100 128 2`7-> is a 7-bit host> is the network bit 25
192.168.1.0 ~ 127
192.168.1.xxxxxxxx
192.168.1.0xxxxxxx
192.168.1.00000000 ~ 01111111
192.168.1.1xxxxxxx
23032 5-bit host network 27
192.168.1.128 ~ 159
192.168.1.1xxxxxxx
192.168.1.100xxxxx
192.168.1.10000000-10011111
192.168.1.101xxxxx
192.168.1.110xxxxx
192.168.1.111xxxxx
. 3 10 4 16-bit network host bits 28
192.168.1.160 ~ 175
. 4 The host machine. 4 bit 3 bit network 29
192.168.1.176 ~ 183 is
In subnetting, the host bits borrowed from the median is the subnet bits
Any of a segment, the head and tail can not use
the name of the first bits are all 0 is the host, the network representative of the
tail bits are all 1 is the host, the network broadcast address on behalf of
the network host bits all 0, represents any network segment any
network host bits all 1s, representing the whole network broadcast address
IPv4 three ways for data dissemination
Unicast :( FIG. 1)
Host A unicast need to transmit the same data BCD
host A will copy data 3 parts, and then encapsulate the destination address of the BCD, sent over the network
advantages: for one-on-one, more security high
disadvantages: host resources, network resources
FIG broadcast :( 2)
By default, all switch interfaces belong to the same broadcast domain
router can be isolated broadcast domain, VLAN broadcast domains can be isolated from
the advantages: replication and transmission of data by a network device, implement, and saves network host resource-intensive
disadvantages: 1. safety 2. low 3. can not manage broadcast storms
multicast :( 3)
Multipoint transmission connection implemented in the receiver and
FIG 1 FIG 2 Broadcast Unicast
Figure 3 Multicast
Network Testing Tools
Use the ping command to diagnose network connectivity
ping172.0.0.1
Verify the local computer is properly configured TCP / IP
ping the local computer address
Verify that it is correctly added to the network
ping ip address of the default gateway
Verify the default gateway is functioning
If it can communicate with a host on the local ip
ping remote host IP
Verify routing traffic through