Network Models and Access Method

Access Method - rules of how data go in and how data go outside the cable.

Two types of access data CSMA(carrier- sense" listening" Multiple access" multiple devices") and Token Ring.

CSMA(carrier- sense" listening" Multiple access" multiple devices") two types:

1. CSMA/CD

• CD stands for Collision Detection
• Each computer on the network including the clients and servers, check the cable for network traffic. (listen - transfer - submit)
• data is sent on at a time
• if data is sent by 2 or more computer at a time, a collision will happen, in which no message will be sent

2.CSMA/AC

• collision Avoidance.
• Queuing to avoid a collision. example of queuing real life (queuing for a blood test, where the patient wait for their turn )

Token passing

• found in a ring topology.
• one token will go round and round (always) from one node to another.
• if a user wants to send a message, wait for the token pass then the user catches the token, so that it can send the message. Then it will be delivered to another user that they want to send to. (it will stop on the receiver then continue again).

Network Models - is the idea to show a standard framework on how the communication of data process design used in a computer the purpose is so we know the step in the network.

two type which is OSI and TCP/IP:

OSI (Open System Interconnection)local network 

• contain 7 layers ("please don't throw sambal pusu away")
• describe the flow of data from one device to another device. 

1. physical - data process to access the network service using the transmission medium (cable) using computer language(binary bits) or transfer data to cable and out of cable using binary(10101011).
2. datalink - (data is divided into frames" transfer data")provide error-free transfer data from one connecter to another through connecting device(datalink is to make sure the data arrived safely onto its destination )(responsible to transport data between networks transfer data between network) it will add MAC address (unique address of devices)
3. network -when it comes on to network it becomes packets to control the flow of data(finding the path of the IP address), deciding which physical path will the data go to - IP address will be identified so that data know the path.
4. transport (segment)- ensure data are sent with no lost or being copied (make sure all the data is being sent completely) use to manage packet delivery 
5. session(data) - allow the formation of the process running on the different station(responsible to start a connection  to establish the connection between sender and receiver) mcm calling kalau receiver answer the call that is the start of the session. 
6. presentation(data)-viewed as "translator" for the network (convert data to language a computer would understand) using ASCII language.
7. application(data) - data process to access the network service (responsible to show information that is needed to show or view the data that are being sent or receive )

TCP/IP (Transmission control protocol/ internet protocol) over the internet 

• contain 4 layers(A.T.I.N.)
• rules that control the communication of a network. 
• it describes the movement of data between source and internet. 

1. application - data process to access the network service when the end user communicates through the internet. 
2. transport - ensure data are sent with no lost or being copied
3. internet - is responsible for addressing, packaging, and routing functions(many ways" finding the best path"). The core protocols of the Internet layer are IP, ARP, ICMP, and IGMP. the message is divided and it will be going many ways.

        4. network access - is responsible for placing TCP/IP packets on the network medium and receiving TCP/IP packets off the network medium.(combine of physical and datalink)

reference: 

Docs.microsoft.com. (2012). TCP/IP Protocol Architecture. [online] Available at: https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-2000-server/cc958821(v=technet.10) [Accessed 25 Apr. 2018].