UML communication diagram - Client server access

"The client–server model of computing is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients. Often clients and servers communicate over a computer network on separate hardware, but both client and server may reside in the same system. A server host runs one or more server programs which share their resources with clients. A client does not share any of its resources, but requests a server's content or service function. Clients therefore initiate communication sessions with servers which await incoming requests.
Examples of computer applications that use the client–server model are Email, network printing, and the World Wide Web." [Client–server model. Wikipedia]
The UML communication diagram example "Client server access" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

"The client–server model of computing is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients. Often clients and servers communicate over a computer network on separate hardware, but both client and server may reside in the same system. A server host runs one or more server programs which share their resources with clients. A client does not share any of its resources, but requests a server's content or service function. Clients therefore initiate communication sessions with servers which await incoming requests.
Examples of computer applications that use the client–server model are Email, network printing, and the World Wide Web." [Client–server model. Wikipedia]
The UML communication diagram example "Client server access" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

"A server is a system (software and suitable computer hardware) that responds to requests across a computer network to provide, or help to provide, a network service. Servers can be run on a dedicated computer, which is also often referred to as "the server", but many networked computers are capable of hosting servers. In many cases, a computer can provide several services and have several servers running.
Servers operate within a client-server architecture. Servers are computer programs running to serve the requests of other programs, the clients. Thus, the server performs some tasks on behalf of clients. The clients typically connect to the server through the network but may run on the same computer. In the context of Internet Protocol (IP) networking, a server is a program that operates as a socket listener.
Servers often provide essential services across a network, either to private users inside a large organization or to public users via the Internet. Typical computing servers are database server, file server, mail server, print server, web server, gaming server, application server, or some other kind of server.
Numerous systems use this client / server networking model including Web sites and email services. An alternative model, peer-to-peer networking enables all computers to act as either a server or client as needed." [Server (computing). Wikipedia]
The UML component diagram example "Start server" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

"Request methods.
An HTTP 1.1 request made using telnet. The request, response headers and response body are highlighted.
HTTP defines methods (sometimes referred to as verbs) to indicate the desired action to be performed on the identified resource. What this resource represents, whether pre-existing data or data that is generated dynamically, depends on the implementation of the server. Often, the resource corresponds to a file or the output of an executable residing on the server. The HTTP/ 1.0 specification:section 8 defined the GET, POST and HEAD methods and the HTTP/ 1.1 specification:section 9 added 5 new methods: OPTIONS, PUT, DELETE, TRACE and CONNECT. By being specified in these documents their semantics are well known and can be depended upon. Any client can use any method and the server can be configured to support any combination of methods. If a method is unknown to an intermediate it will be treated as an unsafe and non-idempotent method. There is no limit to the number of methods that can be defined and this allows for future methods to be specified without breaking existing infrastructure. For example, WebDAV defined 7 new methods and RFC5789 specified the PATCH method.
GET.
Requests a representation of the specified resource. Requests using GET should only retrieve data and should have no other effect. (This is also true of some other HTTP methods.)" [Hypertext Transfer Protocol. Wikipedia]
The UML sequence diagram example "GET request" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.