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, campus, or building, and has its network equipment and interconnects locally managed. LANs facilitate the distribution of da ...
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 o ...
; 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 network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...
.
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 198 ...
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. Before adulthood, a male child or adolescent is referred to as a boy.
Like most other male mammals, a man's genome usually inherits an X chromosome from the mother and a Y chromosome from the f ...
/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. (using the trademark Cisco) is an American multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, s ...
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 discret ...
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 variation of a physical quantity. The protocol defines the rules, syntax, semantics, and synchronization of ...
in use are also given.
Gallery
Image:Virtual Private Network overview.svg, Virtual Private Network
Virtual private network (VPN) is a network architecture for virtually extending a private network (i.e. any computer network which is not the public Internet) across one or multiple other networks which are either untrusted (as they are not con ...
Image:EPN Leased Line and dial-up Network.svg, Enterprise private network
An intranet is a computer network for sharing information, easier communication, collaboration tools, operational systems, and other computing services within an organization, usually to the exclusion of access by outsiders. The term is used in ...
Image:Network Overlay merged.svg, Overlay network
An overlay network is a logical computer network that is protocol layering, layered on top of a physical network. The concept of overlay networking is distinct from the traditional model of OSI model, OSI layered networks, and almost always assum ...
collapsed
Image:Network Overlay.svg, Overlay network
An overlay network is a logical computer network that is protocol layering, layered on top of a physical network. The concept of overlay networking is distinct from the traditional model of OSI model, OSI layered networks, and almost always assum ...
broken-up
Image:XDSL Connectivity Diagram fr.svg, xDSL to Internet connectivity
Image:Internet Connectivity Triple-Play.svg, Triple play
In baseball or softball, a triple play (denoted as TP in baseball statistics) is the act of making three out (baseball), outs during the same play. There have only been 739 triple plays in Major League Baseball (MLB) since 1876, an average of ju ...
illustration
Image:Internet Connectivity Distribution & Core.svg, Internet Distribution and Core
Image:Internet Connectivity An Overview.svg, Internet, Access to core
See also
*
Comparison of network diagram software
*
Computer network
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or b ...
*
Diagram
A diagram is a symbolic Depiction, representation of information using Visualization (graphics), visualization techniques. Diagrams have been used since prehistoric times on Cave painting, walls of caves, but became more prevalent during the Age o ...
*
Network diagram
Graph drawing is an area of mathematics and computer science combining methods from geometric graph theory and information visualization to derive two-dimensional depictions of graphs arising from applications such as social network analysis, c ...
*
Network topology
Network topology is the arrangement of the elements (Data link, links, Node (networking), nodes, etc.) of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, ...
References
{{Commons category, Computer network diagrams
Computer networking
Diagrams