1. Common Agreement
TCP/IP NetBEUI IPX/SPX
1.1 TCP/IP
IP addresses
IP Internet Protocol is the English acronym, meaning "the interconnection between network protocols", which is connected to a computer network to communicate with each other protocols designed. In the Internet, which is connected to all the computer network enables the Internet communicate with each other to achieve a set of rules, the rules specified computers to communicate over the Internet to be followed. Any computer system manufacturers, as long as can be interconnected to comply with the IP protocol interworking with the Internet. It is because of IP protocol, the Internet was able to quickly become the world's largest open computer communications network. Therefore, IP protocol can also be called "Internet protocol."
IP addresses are used to computers on the Internet a number. Daily situation we see is we need to have IP addresses can not communicate on each networked PC. We can "PC" to a "one call", then the "IP address" is equivalent to "phone number", but in the Internet router, the equivalent of the bureau of "program-controlled switches."
Gateway
Gateway (Gateway), also known as gateways, protocol converters. Implemented in a gateway above the network layer internetworking, is the most complex of the internetworking device, only two different high-level protocol for network interconnection. Gateway can be used for both WAN interconnection, it can also be used for LAN interconnection. Gateway is a computer system or a device for converting the task of acting as. Using different communication protocols, data formats, or language, or even completely different architecture systems, a gateway translator. And bridges simply convey different information, the gateway to the information received repackaged to meet the needs of the destination system. The same layer - application layer.
Subnet Mask
Subnet Mask (subnet mask) called network mask, the mask address, subnet mask, which is a bit used to indicate which IP address is identified by a subnet host resides, and the identification of which bits is the host of bit mask. Subnet mask can not exist alone, it must be combined with the IP address. The subnet mask is only one role, is to divide an IP address into a network and host addresses in two parts.
The subnet mask is a 32-bit address, for shielding a part of the IP address in network identifier and host identifier distinguish and indicate that the IP address is on the LAN, or on a remote network.
DNS server
DNS (Domain Name System, DNS), a distributed database as names and IP addresses on the World Wide Web mapped each other, enable the user easier access to the Internet, without having to remember the IP number of strings can be directly read by a machine. A domain name, the domain corresponding to the finally obtained IP address is called name resolution process (or host name resolution). DNS protocol runs over UDP protocol that uses port 53. In the document, RFC 2181 RFC have to DNS specification, RFC 2136 DNS dynamic update is explained, RFC 2308 on a reverse DNS lookup cache explained.
2. OSI / RM model
Application layer
The seventh layer application layer, the application layer provides the interface to access network services to the operating system or network applications.
Represents the application layer protocols include: Telnet, FTP, HTTP, SNMP and the like.
DHCP ·DNS · FTP · Gopher · HTTP· IMAP4 · IRC · NNTP · XMPP ·POP3 · SIP · SMTP ·SNMP · SSH ·TELNET · RPC · RTCP · RTP ·RTSP· SDP · SOAP · GTP · STUN · NTP· SSDP · BGP · RIP 等
表示层
The sixth layer is a layer
This layer is mainly to solve the problem of representing grammatical information support. It is to be switched from the data suitable for a user's abstract syntax, suitable for converting the internal transfer syntax OSI systems. Providing representation and convert the data formatting services. Compression and decompression of data, encryption and decryption work by the presentation layer is responsible.
Session Layer
The fifth layer is the session layer
This layer may also be referred to a meeting layer or session layer, session layer and above the high level, the unit of data transmission no additional names, referred to as packets. Session layer does not participate in a particular transmission, it provides a mechanism for communication between the establishment and maintenance of applications including access, including authentication and session management. Such as server authenticates the user login is completed by the session layer.
Transport Layer
The fourth layer is the transport layer processing information. A fourth layer data unit also referred to as packets (packets). However, when you talk about specific TCP and other protocols have a special name for, TCP data units called segments (segments) and UDP protocol data unit called "datagrams (datagrams)". This layer is responsible for acquiring all the information, therefore, it must keep track of the data unit fragments arrive out of order packets and other hazards which may occur during transmission. Layer 4 provides for the upper end (end user to end user) transparent and reliable data transmission services. The transparent transport means in the transport layer of the communication process, specific details shields the upper communication transmission system.
Representatives of transport layer protocols include: TCP, UDP, SPX and so on.
TCP · UDP · TLS · DCCP · SCTP · RSVP · OSPF 等
TCP and UDP in the transport layer. It provides communication services between the data transfer between the application node, the main function is to format the data, and retransmission of lost data confirm the like. The Transmission Control Protocol (TCP), User Datagram Protocol packets (UDP), etc., TCP and UDP packet is added to the transmission data and transfers it to the next layer, this layer is responsible for transmitting data, and determines that the data has been sent up to and receives.
TCP and UDP are based on the IP.
Network layer
The third layer is the network layer
May go through a lot of data link communications between two computers in a computer network, it may go through a lot of subnetworks. The task is to choose the appropriate network layer routing and inter-network switching nodes, to ensure the timely delivery of data. Frames the packet network layer provides data link layer, the network layer packets are encapsulated header, which contains information of the logical address - - Network address of the source site and destination site address.
If you're talking about an IP address, then you are dealing with the issue of the third layer, which is the "packet" problem, rather than a "frame" the second layer. Is part of Layer 3 IP problem, and in addition there are a number of routing protocols Address Resolution Protocol (ARP). Everything about routing in Layer 3 processing. Address resolution and routing is an important objective of 3 layers. Network congestion control layer can also be achieved, internetworking functions.
In this layer, data units called packets (packet).
Represents the network layer protocols include: IP, IPX, RIP, OSPF and the like.
IP (IPv4 · IPv6) · ICMP· ICMPv6·IGMP ·IS-IS · IPsec · ARP · RARP等
IP layer in the interconnection network. Responsible for providing the basic data packet transmission function, so that every piece of data packets can reach the destination host (but do not check was received correctly).
data link layer
Second layer: data link layer (DataLinkLayer): in the physical layer bit stream based on the service, establishing a data link between adjacent nodes, by providing error control data frame (Frame) in an error-free channel transmission, and the operation on each series circuit.
The data link layer provides reliable transmission over unreliable physical media. This layer serves comprising: addressing a physical address, data framing, flow control, error detection data, such as retransmission.
In this layer, a data unit called a frame (frame).
Representative data link layer protocol comprises: SDLC, HDLC, PPP, STP, FR.
Wi-Fi (IEEE 802.11) · WiMAX (IEEE 802.16) · ATM · DTM · · the FDDI token ring Ethernet · · FR · GPRS · EVDO · HSPA · HDLC · PPP · L2TP · PPTP · ISDN · STP etc.
Physical Layer
The first layer: the mechanical characteristics of the physical layer (PhysicalLayer), a predetermined communication device, electrical, functional and processes for establishing, maintaining and removing the physical link connection. In particular, the mechanical properties of a predetermined size specifications required for network connection of the connector, the number and arrangement of pins and the like; the size of the electrical characteristics of a predetermined transmission bit physical connection on the line when the signal level of the stream, the impedance matching, distance transmission rate restrictions; it refers to features of the respective first signal a signal distribution exact meaning, i.e., defines the function of each line between the DTE and the DCE; protocol defines a set of characteristic procedures by the signal transmission lines bit stream, It means to establish a physical connection, maintenance, exchange information, DTE, and bis DCE placed on each operation of the series circuit.
In this layer, data units called bits (bit).
Typical Specification behalf of the physical layer defined include: EIA / TIA RS-232, EIA / TIA RS-449, V.35, RJ-45 and the like.
· · Ethernet modem line communication (PLC) · SONET / SDH · G.709 · · twisted fiber-coax
Application of layers of the data to the transport layer
Automatically transmitting the data layers is divided into several udp tcp packets or packets, the packets are time division tcp added to each packet header or udp (port number added so many information) then these packets to the network layer.
The network layer packet tcp or udp each packet transmitted is subdivided into a plurality of packets ip, ip header is added (added local ip address, destination address, etc. information ip), the network interface layer is then down
Network interface layer to the physical devices used, according to the destination NIC ip address query to mac address, the data to the reception side.
The receiver layer provides a network interface to the network layer packet ip
The transport layer then be combined ip tcp packets or packet udp
Network layer and then back up the data to the application layer.