"How to run up the computer" || Chapter IX • through seven simple experiments to understand TCP / IP network

Author: Hisao Yazawa

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• Chapter IX through seven simple experiments to understand TCP / IP network

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[00] Basics

• LAN: Local Area Network LAN
• WAN: Wide Area Network WAN
• TCP / IP: Transmission Control Protocol / Internet Protocol Transmission Control Protocol / Internet Protocol
• MAC Address: the ability to identify the number of the card. All the card will be assigned an irrevocable prior to listing the MAC address
• Protocol: The computer to exchange information, to be determined in advance occurs manner between the sender and the receiver, and this information transmission mode or a predetermined constraints is called "Protocol"

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[01] experimental environment

It relates to a device

• server
• Client
• Hub (Hub): responsible for each computer network cable connected to one another along the assembly line equipment
• Router (Router): responsible for network and Internet connection up within the company (responsible for connecting the LAN to the WAN)

End router will connect to the router Internet service provider, and the service provider, will continue to connect their router to the other routers in this way ultimately access to the Internet backbone cable.

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[02] see the MAC address of the network card

Send and receive information to first understand the CSMA / CD mechanism.

Career Sense Multiple Access with Collision Detection: with Collision Detection Carrier Sense Multiple Access

• Carrier Sense: this mechanism will go to listen (Sense) represents the electrical signal (Career) whether the network is being used
• Multiplexing: a plurality of devices may simultaneously access the transmission medium
• With Collision Detection: that this mechanism would go detection (Detection) electrical signal conflict (Collision) due to transmission caused by the same time
  

How to check card's MAC address?

Upon receipt of a computer to do first electrical signal is determined, if it is sent to their receiving is selected, otherwise choose to ignore; can be referred to as a MAC address numbers to develop an electrical signal receiver.

Each piece of card carried by all pre-ROM burn a unique MAC address

We can enter the command prompt, type:ipconfig/all To check their computer's MAC address.

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[03] see the computer's IP address

Now that you have a MAC address uniquely identifies your computer, so why have an IP address.

Because the simple MAC address can cause inconvenient for group management on the computer, but with the IP address, we can quickly find the same zip code as the destination information to be transmitted.

We usually host , refers to a set computer IP addresses.

In the TCP / IP network, the data transmission will be with two MAC and IP addresses.

IP addresses

• 32bit integer, each 8bit as a group, the group with "." Separated, is divided into four segments represented
• After 8bit integer expressed in terms of decimal range is 0-255, so the available IP addresses is an integer 0.0.0.0--255.255.255.255
• The computer can easily be grouped for management (network address + host address) by IP address

Subnet Mask (Subnet Mask)

• Role is to identify the IP address of 32bit, from which a network address where one is, where one is the one from which the host address
• Such as subnet mask of 255.255.255.0 binary conversion, a value of 1 corresponds to the network address of the IP address, a host address corresponding to a value of 0, so the range of host addresses 00000001-11111110

We can also open a command prompt, type:ipconfig/all To query the host's IP address.

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[04] understand the DHCP server role

• DHCP: Dynamic Host Configuration Protocol (Dynamic Host Configuration Protocol)
• DHCP server may be recorded on a computer assigned to the LAN IP address and subnet mask range
• In the check the "automatically obtain IP address" will get the IP address and subnet mask from the DHCP server option, the computer starts and automatically configure them

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[05] router is guiding people in the process of data transmission

• Router is the same as with other computers attached to the hub
• Within the LAN using CSMA / CD mechanism, so all data sent will be sent to the router
• Router works: to view additional network address part of the IP address on the data, found that the data is not sent to the computer in the LAN'll send it to the Internet
• Routing Table: used to record information should forward the data to where; a router's routing table will record the path leading to the neighboring router.
• Observe the routing table: Open a command prompt, enter route print

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[06] see the router's routing process

Routing: router forwards data through the process called "routing"

Track routing process: Open a command prompt type tracert destination URL

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[07] DNS server can resolve the host name to an IP address

• DNS: Domain Name System Domain Name System
• DNS servers can be domain name (www.baidu.com) into IP addresses
• FQDN: Fully Qualified Domain Name fully qualified domain name, will combine the host and domain name
• DNS server is typically deployed in each of the LAN, which is recorded the correspondence table FQDN and the IP address
• DNS servers around the world are mutual cooperation, a domain name can not be resolved, it will go to ask other DNS servers
• View Host Name: Open a command prompt enter the hostname
• Asks the DNS server: Open a command prompt, enter nslookup

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[08] see the IP address and MAC address of the correspondence between

• ARP: Address Resolution Protocol ARP; the IP address-to-MAC address
• ARP cache table: When asked to complete an individual computer, able to keep the obtained MAC address and IP address correspondence cached
• View the ARP cache: Open a command prompt type-A arp
  
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[09] hierarchical model of the role of TCP and TCP / IP networks

• IP protocol is used to specify the IP address of the destination data and forwarding data through the router
• TCP protocol for the other signal response confirmation sent by each sender and receiver of data, reliable transmission of data; usually this data transfer mode is referred to as the "handshake"
  

TCP protocol also provides for the sender to put data into the original large "package" as a unit of the data unit, and then transmitted, and the receiver should receive the packet assembled together to restore original data

TCP / IP network-level model

Additional layers of data to be re-sent to the various protocol information

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