Which OSI layer is NFS

Introduction to the TCP / IP protocol family

This section provides a comprehensive introduction to the protocols contained in TCP / IP. Although this information is provided as a background, you should know the names of the logs. In addition, you should know what each individual protocol is supposed to do.

“TCP / IP” is an acronym often used for the set of network protocols that make up the Internet Protocol family composed. The term “Internet” is often used to describe both the protocol family and the global WAN network. In this book, “TCP / IP” refers only to the Internet Protocol family. “Internet” refers to the wide area network (WAN) and the facilities that monitor the Internet.

In order to network your TCP / IP network with other networks, you must obtain a unique IP address for your network. At the time of this publication, you obtained this address from an Internet Service Provider (ISP).

If you want hosts on your network to participate in the Internet Domain Name System (DNS), you must obtain and register a unique domain name. The registration of domain names is coordinated by InterNIC through a group of worldwide databases. For more information on DNS, see the System Administration Guide: Naming Services and Directory Services (DNS, NIS, and LDAP).

Protocol layers and the Open Systems Interconnection model

Most network protocol families are divided into several layers, which in their entirety are also called Protocol stack are designated. Each layer has a specific purpose. Each layer is present on both the sending and receiving systems. A certain layer of a system sends or receives exactly the same object that the Peer process another system sent or received. These activities occur independently of other activities in the layers above or below the considered layer. In principle, each layer of a system acts independently of the other layers on the same system. Each layer acts in parallel with the same layer on other systems.

OSI reference model

Most network protocol families are built in layers. The International Organization for Standardization (ISO) designed the Open Systems Interconnection (OSI) reference model, which uses structured layers. The OSI model describes a structure of seven layers for network activities. At least one protocol is assigned to each layer. The layers represent the data transmission processes that are common to all types of data transmission between cooperating networks.

The OSI model lists the protocol layers from the top (layer 7) to the bottom (layer 1). This model is shown in the following table.

Table 1-1 OSI reference model

Includes the standard communication services and applications that the user will work with.
Ensures that information is delivered to the receiving system in such a way that it can be understood by the system.
Manages the connections and closures between cooperating systems.
Manages the data transfer. It also ensures that the data received matches the data sent.
Manages data addressing and communication between networks.
Handles the transmission of data over the network media.
Defines the properties of the network hardware.

The OSI model defines conceptual processes that are not tied to any particular network protocol family. For example, the OSI network protocol family implements all seven layers of the OSI model. TCP / IP also uses some layers of the OSI model, and groups together other layers. Other network protocols, e.g. B. SNA, use an additional eighth layer.

Model of the TCP / IP protocol architecture

The OSI model describes idealized network connections with a protocol family. In this model, TCP / IP only partially corresponds. It connects z. B. several OSI layers to one layer or does not use other layers at all. The following table lists the layers of implementation of TCP / IP in Oracle Solaris. The following table shows the layers from the top layer (application) to the bottom layer (bit transmission).

Table 1-2 TCP / IP protocol stacks

Corresponding OSI layer
TCP / IP protocol examples
Application, meeting, presentation
NFS, NIS, DNS, LDAP,,,,,, RIP, RDISC, SNMP and others
Ethernet (IEEE 802.3), Token Ring, RS-232, FDDI and others

The table shows the TCP / IP protocol layers and their equivalents in the OSI model. It also provides examples of the protocols available at each layer in the TCP / IP protocol stack. Each system involved in a data exchange performs a one-time implementation of the protocol stack.

Physical layer

The Physical layer defines the properties of the hardware used for the network. For example, the physical layer determines the physical properties of the communication media. The physical layer in the TCP / IP protocol describes hardware standards such as IEEE 802.3, the specifications for Ethernet network media, and RS-232, the specifications for standard pin connectors.

Data link layer

The Data link layer identifies the network protocol type of the packet, in this case TCP / IP. In addition, the data link layer offers error control and data framing. Examples of protocols in the data link layer are Ethernet IEEE 802.2 framing and Point-to-Point Protocol (PPP) framing.

Network layer

The network layer, also known as the Internet layer or IP layer accepts packets and forwards them to the network. This layer comprises the powerful Internet Protocol (IP), the Address Resolution Protocol (ARP) and the Internet Control Message Protocol (ICMP).

IP protocol

The IP protocol and the associated routing protocols are probably the most important protocols in the entire TCP / IP protocol family. The IP protocol is responsible for the following:

  • IP addressing - the IP addressing conventions are part of the IP protocol. Creating an IPv4 Addressing Scheme provides an introduction to IPv4 addressing, Introduction to IPv6 Addressing, IPv6 Addressing.

  • Host to host communication - The IP protocol determines the path a packet must take based on the IP address of the receiving system.

  • Package formatting - The IP protocol combines data packets into units that are called Datagrams are designated. Datagrams are described in detail under Internet Layer: Preparing Packets for Delivery.

  • Fragmentation - If a packet is too large to be transmitted over the network medium, the IP protocol breaks the packet down into smaller fragments on the sending system. The IP protocol on the receiving system then reassembles the fragments to form the original packet.

Oracle Solaris supports the IPv4 and IPv6 addressing formats, both of which are described in this guide. To avoid misunderstandings, one of the following conventions is used when designating the Internet Protocol versions:

  • When the term “IP” is used in a description, the description applies to both IPv4 and IPv6.

  • If the term “IPv4” is used in a description, the description only applies to IPv4.

  • If the term “IPv6” is used in a description, the description only applies to IPv6.

ARP protocol

The Address Resolution Protocol (ARP) is located between the security and network layers. ARP supports the IP protocol in routing datagrams to the correct receiving system by assigning Ethernet addresses (with a length of 48 bits) to known IP addresses (with a length of 32 bits).

ICMP protocol

The Internet Control Message Protocol (ICMP) detects and reports error states in the network. ICMP reports the following:

  • Lost packages - Packages that arrive too quickly to be processed

  • Connectivity failure - A target system cannot be reached

  • detour - Redirecting a sending system so that it uses a different router

Chapter 8, Administering a TCP / IP Network (Tasks) provides more information about the Oracle Solaris commands that use the ICMP protocol to detect problems.

Transport layer

The Transport layer in the TCP / IP protocol ensures that packets arrive one after the other and without errors by sending confirmations for the receipt of data and retransmitting lost packets. This type of communication is called continuous (end-to-end) Called communication. Transport-layer protocols at this level are Transmission Control Protocol (TCP), User Datagram Protocol (UDP) and Stream Control Transmission Protocol (SCTP). TCP and SCTP provide reliable end-to-end services. UDP provides unreliable datagram service.

TCP protocol

TCP ensures that applications can communicate with one another as if they were firmly connected to one another via a circuit. TCP sends data character by character instead of in discrete packets. The transmission consists of the following:

  • Starting point that opens the connection.

  • Entire transfer in byte order.

  • Endpoint that closes the connection.

TCP adds a header to the transmitted data. This header contains numerous parameters that help processes on the sending system to connect to the peer processes on the receiving system.

TCP confirms that a packet has reached its destination by establishing an end-to-end connection between the sending and receiving hosts. Therefore, TCP is called a "reliable, connection-oriented" protocol.

SCTP protocol

SCTP is a reliable, connection-oriented transport-layer protocol that provides applications with the same services as the TCP protocol. In addition, the SCTP protocol can also support connections between systems that have multiple addresses (Multihomed systems). The SCTP connection between the sending and the receiving system is called association designated. Data in the association is divided into data blocks. Since the SCTP protocol supports multihoming, certain applications (especially applications for the telecommunications industry) must be executed via SCTP instead of TCP.

UDP protocol

UDP offers a delivery service for datagrams. UDP does not check connections between sending and receiving hosts. Because UDP does not perform any processes to establish and verify connections, applications that send only small amounts of data use the UDP protocol.

Application layer

The Application layer defines standard Internet services and network applications that anyone can use. These services work together with the transport layer to send and receive data. Various protocols exist on the application layer. The following list shows examples of application layer protocols:

  • Standard TCP / IP services such as B., and commands

  • UNIX "r" commands, e.g. Federation

  • Name services, e.g. B. NIS and Domain Name Service (DNS)

  • Directory Services (LDAP)

  • File services, e.g. B. the NFS service

  • Simple Network Management Protocol (SNMP), which enables network management

  • The routing protocols Router Discovery Server Protocol (RDISC) and Routing Information Protocol (RIP)

Standard TCP / IP services
  • FTP and Anonymous FTP - The File Transfer Protocol (FTP) transfers files to and from a remote network. The protocol includes the command and the daemon. FTP allows a user to enter the name of a remote host and file transfer command options at the local host's command line. The daemon on the remote host then processes the requests from the local host. Unlike, works correctly even if the remote computer is not running a UNIX-based operating system. To establish a connection, a user must log into the remote system, unless the remote system allows anonymous FTP.

    You can transfer enormous amounts of data from anonymous FTP servers that are connected to the Internet. These servers were set up by universities and other institutions, among others, to make software, research materials and other information available to the public. When you log in to these servers, you use the login name, hence the name "Anonymous FTP Server."

    The use of anonymous FTP and the setting up of anonymous FTP servers are not described in this manual. However, anonymous FTP is used in many books such as B. The Whole Internet User's Guide & Catalog described in detail. For instructions on using FTP, see the System Administration Guide: Network Services. The man page (1) describes all command options that are called via the command interpreter. The man page (1M) describes all services that are provided by the daemon.

  • Telnet - With the Telnet protocol, terminals and terminal-oriented processes can communicate with one another via a network that uses TCP / IP. This protocol is implemented as a program on local systems and as a daemon on remote computers. Telnet provides a user interface that allows two hosts to communicate with each other by character or line. Telnet comprises various commands that are documented in detail in the man page (1).

  • TFTP - The Trivial File Transfer Protocol () offers functions similar to, but the protocol does not establish an interactive connection like. For this reason, users cannot view the contents of a directory or switch directories. A user needs to know the full name of a file to be copied. The instruction set of is described in detail in man page (1).

UNIX "r" commands

The UNIX "r" commands allow users to enter commands on their local computers that are run on the remote host. These include the following commands:

Instructions for using these commands can be found in man pages (1), (1), and (1).

Name services

Oracle Solaris offers the following naming services:

  • DNS - Domain Name Service (DNS) is one of the name services provided by the Internet for TCP / IP networks. DNS resolves host names to IP addresses. In addition, DNS serves as a database for mail management. A full description of this service can be found in the System Administration Guide: Naming Services and Directory Services (DNS, NIS, and LDAP). For more information, see the (3RESOLV) man page.

  • -Files - This originally host-based UNIX name system was developed for stand-alone UNIX computers and then adopted for use in the network. Many old UNIX operating systems and computers still use this system, although it is unsuitable for large and complex networks.

  • NIS - The Network Information Service (NIS) was developed independently of DNS and has a slightly different task. While DNS simplifies connections by using computer names instead of numeric IP addresses, NIS focuses on simplifying network management by allowing centralized control of various network information. NIS stores information about computer names and addresses, users, the network itself, and network services. The NIS namespace information is stored in NIS maps. For more information on NIS architecture and management, see the System Administration Guide: Naming Services and Directory Services (DNS, NIS, and LDAP).

Directory service

Oracle Solaris supports the Lightweight Directory Access Protocol (LDAP) together with the Sun Open Net Environment (Sun ONE) directory server and other LDAP directory servers. The difference between a name service and a directory service lies in the range of functions. A directory service offers the same range of functions as a name service and also has extended functions. Read about it System Administration Guide: Naming Services and Directory Services (DNS, NIS, and LDAP).

File services

The NFS application layer protocol provides file services for Oracle Solaris. You can find detailed information about the NFS service in the System Administration Guide: Network Services.

Network management

The Simple Network Management Protocol (SNMP) lets you view the layout of your network and the status of major computers. In addition, with SNMP you can obtain complex network statistics from programs based on a graphical user interface (GUI). Many companies offer program packages for network administration that implement SNMP.

Routing protocols

Routing Information Protocol (RIP) and Router Discovery Server Protocol (RDISC) are two available routing protocols for TCP / IP networks. For a complete list of the available routing protocols for Oracle Solaris 10, see Table 5-1 and Table 5-2.

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