Internetworking is a way of connecting a computer network to other networks using gateways that provide a common routing order for information packets between networks. The resulting system of interconnected networks is called a composite network , or simply an Internet.
The most striking example of interconnection is the Internet , a network of networks based on many basic equipment technologies, but combined with a standard set of internetworking protocols known as TCP / IP .
The simplest example of a composite network is two local area networks connected via a router . Using a switch or hub to connect local networks does not imply interworking , but only extends the original network.
Networking
Networking was developed as a way to connect completely different types of network technologies, but has become popular due to the growing need to connect two or more local networks through some kind of global network . The original term for interworking was catenet [1] .
Today, the definition of interworking involves connecting other types of computer networks, such as personal computer networks . Network elements for connecting separate networks in arpanet , the predecessor of the Internet, were originally called gateways , but the term is outdated in this context because of the possibility of confusion between the names of functionally different devices. Today, adjacent gateways are called routers .
Another type of network interconnection is typically used within the enterprise at the link layer of the OSI network model, that is, at the hardware-oriented level of the TCP / IP protocol stack. Such interconnection is carried out using network bridges and switches . This type of interaction is sometimes incorrectly called a gateway, but the resulting system is simply a larger single subnet, and no gateway protocol, such as IP, is required for such networks to work. However, any computer network can be converted to an intranet by dividing the network into segments and logically dividing the traffic into segments by the router. The IP protocol is designed to provide unreliable (not guaranteed) packet service throughout the network. Such an architecture avoids intermediate network elements to maintain any state of the network. On the contrary, this function is assigned to the endpoints of each communication session. For reliable data transfer, applications must use appropriate transport layer protocols, such as Transmission Control Protocol (TCP), which provides reliable data flow. Some applications for tasks that do not require reliable data delivery or require real-time packet delivery, such as streaming video [2] or voice chat, use a simpler transport protocol without establishing a connection, User Datagram Protocol (udp).
Network Models
Two architectural models are used to describe the protocols and methods used in the interworking.
The Open Source Interoperability Base Model (OSI model) was developed under the auspices of the International Organization for Standardization (ISO) and provides an accurate description of the levels of protocol operation from the base hardware to the software interface in the user application. Interworking is implemented in the network layer (layer 3) of the model.
The set of network data transfer protocols, the so-called TCP / IP protocol , was not developed in accordance with the OSI model and does not refer to it in any regulatory specifications of the Work Proposal (RFC) and Internet Standards (STD) . Despite the similar appearance of a multi-level model, it uses a much less rigorous, freely definable architecture, which concerns only aspects of logical networks. It does not include a description of hardware low-level interfaces, and assumes the availability of the data link layer interface for local networks through a connected host. Internetworking operates with its Internet layer protocols.
See also
- Internet history
Notes
- ↑ Surf Winton. The Catenet Model for internetworking (TXT). RFC Editor . www.rfc-editor.org (July 1978).
- ↑ Teare, Diane (July 1999).