OSI seven-layer model
OSI seven-layer reference model
People must learn computers are not new to the OSI reference model, OSI seven layer reference model is the International Organization for Standardization (ISO) to develop a standard system for communication between computer systems or interconnected. It is a seven-layer model abstract body, including not only a series of abstract terms and concepts, including the specific protocol
So, OSI seven-layer reference model which includes seven layers of it?
Stratified:
- Application layer
# Interface network services and end users. # Protocols are: HTTP FTP TFTP SMTP SNMP DNS TELNET HTTPS POP3 DHCP
- Presentation layer
# Representing data, security, compression. (Five in the model which has been incorporated into the application layer) # format, JPEG, ASCll, DECOIC, encrypted format
- Session Layer
# Establishment, management, terminating the session. (In five model which has been incorporated into the application layer) # corresponding to the host process, means the local host and the remote host ongoing session
- Transport Layer
# , As well as flow control and error checking. # Agreement: TCP UDP, i.e., once the packet leaves the network adapter into the network transport layer
- Network layer
# Logical address addressing, routing implemented between different networks. # Agreement: ICMP IGMP IP (IPV4 IPV6) ARP RARP
- data link layer
# Establishing a logical connection, hardware address addressing, error checking and [2] and so on. (Defined by the underlying network protocol) # the bits into bytes and then combined into frames, using the MAC address access media, an error is found but not corrected.
- Physical Layer
# Establishment, maintenance, disconnect the physical connection. (Defined by the underlying network protocol)
# , Between the application layer protocol TCP / IP hierarchical model structure by calling stepwise transport layer (Transport layer), mesh # network layer (Network Layer) data link layer and a physical (Physical Data Link) can be realized in the application layer # application communication interconnection. # Application layer applications need to care about the details of the logic, instead of data transmission activity in the network. The application layer is the lower three layers of # processing real communication details. All thought the Internet throughout the development process and the focus are called to # exist Document Format RFC (Request For Comments) are. For each specific TCP / IP use, # there is a corresponding RFC [3] document. # Some typical TCP / IP applications are FTP, Telnet, SMTP, SNTP, REXEC, TFTP, LPD, # SNMP, NFS, INETD and so on. RFC substantially the same so that some TCP / IP applications are standardized, so that different manufacturers # developed applications can be mutually
