A computer network diagram is a schematic depicting the nodes and connections amongst nodes in a computer network or, more generally, any telecommunications network. Computer network diagrams form an important part of network documentation.

Symbolization

Readily identifiable icons are used to depict common network appliances, e.g. routers, and the style of lines between them indicates the type of connection. Clouds are used to represent networks external to the one pictured for the purposes of depicting connections between internal and external devices, without indicating the specifics of the outside network. For example, in the hypothetical

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a large ...

pictured to the right, three personal computers and a server are connected to a

switch In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...

; the server is further connected to a printer and a gateway router, which is connected via a WAN link to the

Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, p ...

. Depending on whether the diagram is intended for formal or informal use, certain details may be lacking and must be determined from context. For example, the sample diagram does not indicate the physical type of connection between the PCs and the switch, but since a modern LAN is depicted,

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1 ...

may be assumed. If the same style of line was used in a WAN (wide area network) diagram, however, it may indicate a different type of connection. At different scales diagrams may represent various levels of network granularity. At the LAN level, individual nodes may represent individual physical devices, such as hubs or file servers, while at the WAN level, individual nodes may represent entire cities. In addition, when the scope of a diagram crosses the common LAN/

MAN A man is an adult male human. Prior to adulthood, a male human is referred to as a boy (a male child or adolescent). Like most other male mammals, a man's genome usually inherits an X chromosome from the mother and a Y chromo ...

/WAN boundaries, representative hypothetical devices may be depicted instead of showing all actually existing nodes. For example, if a network appliance is intended to be connected through the Internet to many end-user mobile devices, only a single such device may be depicted for the purposes of showing the general relationship between the appliance and any such device.

Cisco symbolization

Cisco Cisco Systems, Inc., commonly known as Cisco, is an American-based multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, ...

uses its own brand of networking symbols. Since Cisco has a large Internet presence and designs a broad variety of network devices, its list of symbols ("Network Topology Icons") is exhaustive.

Topology

The ''physical'' network topology can be directly represented in a network diagram, as it is simply the physical

graph Graph may refer to: Mathematics *Graph (discrete mathematics), a structure made of vertices and edges **Graph theory, the study of such graphs and their properties *Graph (topology), a topological space resembling a graph in the sense of discre ...

represented by the diagrams, with network nodes as vertices and connections as undirected or direct edges (depending on the type of connection). The ''logical'' network topology can be inferred from the network diagram if details of the

network protocols A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchroniza ...

in use are also given.

Gallery

Image:Virtual Private Network overview.svg,

Virtual Private Network A virtual private network (VPN) extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. The b ...

Image:EPN Leased Line and dial-up Network.svg, Enterprise private network Image:Network Overlay merged.svg,

Overlay network An overlay network is a computer network that is layered on top of another network. Structure Nodes in the overlay network can be thought of as being connected by virtual or logical links, each of which corresponds to a path, perhaps through ...

collapsed Image:Network Overlay.svg,

broken-up Image:XDSL Connectivity Diagram fr.svg, xDSL to Internet connectivity Image:Internet Connectivity Triple-Play.svg, Triple play illustration Image:Internet Connectivity Distribution & Core.svg, Internet Distribution and Core Image:Internet Connectivity An Overview.svg, Internet, Access to core

References

{{Commons category, Computer network diagrams Computer networking Diagrams

Symbolization

Cisco symbolization

Topology

Gallery

See also

References