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Publish–subscribe Pattern
In software architecture, publish–subscribe is a messaging pattern where senders of messages, called publishers, do not program the messages to be sent directly to specific receivers, called subscribers, but instead categorize published messages into classes without knowledge of which subscribers, if any, there may be. Similarly, subscribers express interest in one or more classes and only receive messages that are of interest, without knowledge of which publishers, if any, there are. Publish–subscribe is a sibling of the message queue paradigm, and is typically one part of a larger message-oriented middleware system. Most messaging systems support both the pub/sub and message queue models in their API; e.g., Java Message Service (JMS). This pattern provides greater network scalability and a more dynamic network topology, with a resulting decreased flexibility to modify the publisher and the structure of the published data. Message filtering In the publish-subscribe mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Architecture
Software architecture is the fundamental structure of a software system and the discipline of creating such structures and systems. Each structure comprises software elements, relations among them, and properties of both elements and relations. The ''architecture'' of a software system is a metaphor, analogous to the architecture of a building. It functions as a blueprint for the system and the developing project, which project management can later use to extrapolate the tasks necessary to be executed by the teams and people involved. Software architecture is about making fundamental structural choices that are costly to change once implemented. Software architecture choices include specific structural options from possibilities in the design of the software. For example, the systems that controlled the Space Shuttle launch vehicle had the requirement of being very fast and very reliable. Therefore, an appropriate real-time computing language would need to be chosen. Addition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small-world Routing
In network theory, small-world routing refers to routing methods for small-world networks. Networks of this type are peculiar in that relatively short paths exist between any two nodes. Determining these paths, however, can be a difficult problem from the perspective of an individual routing node in the network if no further information is known about the network as a whole. Greedy routing Nearly every solution to the problem of routing in small world involves the application of greedy routing. This sort of routing depends on a relative reference point by which any node in the path can choose the next node it believes is closest to the destination. That is, there must be something to be greedy about. For example, this could be geographic location, IP address, etc. In the case of Milgram's original small-world experiment, participants knew the location and occupation of the final recipient and could therefore forward messages based on those parameters. Constructing a reference b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transport Layer Security
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible. The TLS protocol aims primarily to provide security, including privacy (confidentiality), integrity, and authenticity through the use of cryptography, such as the use of certificates, between two or more communicating computer applications. It runs in the presentation layer and is itself composed of two layers: the TLS record and the TLS handshake protocols. The closely related Datagram Transport Layer Security (DTLS) is a communications protocol providing security to datagram-based applications. In technical writing you often you will see references to (D)TLS when it applies to both versions. TLS is a proposed Internet Engineering Task Force (IETF) standard, first defined in 1999, and the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encryption
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decipher a ciphertext back to plaintext and access the original information. Encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. For technical reasons, an encryption scheme usually uses a pseudo-random encryption key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users. Historically, various forms of encryption have been used to aid in cryptography. Early encryption techniques were often used in military ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicast
In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast should not be confused with physical layer point-to-multipoint communication. Group communication may either be application layer multicast or network-assisted multicast, where the latter makes it possible for the source to efficiently send to the group in a single transmission. Copies are automatically created in other network elements, such as routers, switches and cellular network base stations, but only to network segments that currently contain members of the group. Network assisted multicast may be implemented at the data link layer using one-to-many addressing and switching such as Ethernet multicast addressing, Asynchronous Transfer Mode (ATM), point-to-multipoint virtual circuits (P2MP) or InfiniBand multicast. Network-assisted multicast may also be impl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadcasting (networking)
In computer networking, telecommunication and information theory, broadcasting is a method of transferring a message to all recipients simultaneously. Broadcasting can be performed as a high-level operation in a program, for example, broadcasting in Message Passing Interface, or it may be a low-level networking operation, for example broadcasting on Ethernet. All-to-all communication is a computer communication method in which each sender transmits messages to all receivers within a group. In networking this can be accomplished using broadcast or multicast. This is in contrast with the point-to-point method in which each sender communicates with one receiver. Addressing methods There are four principal addressing methods in the Internet Protocol: Overview In computer networking, broadcasting refers to transmitting a packet that will be received by every device on the network. In practice, the scope of the broadcast is limited to a broadcast domain. Broadcasting is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In-band Control
{{Unreferenced, date=June 2019, bot=noref (GreenC bot) In-band control is a characteristic of network protocols with which data control is regulated. In-band control passes control data on the same connection as main data. Protocols that use in-band control include HTTP and SMTP. This is as opposed to Out-of-band control used by protocols such as FTP. Example Here is an example of an SMTP client-server interaction: Server: 220 example.com Client: HELO example.net Server: 250 Hello example.net, pleased to meet you Client: MAIL FROM: Server: 250 jane.doe@example.net... Sender ok Client: RCPT TO: Server: 250 john.doe@example.com ... Recipient ok Client: DATA Server: 354 Enter mail, end with "." on a line by itself Client: Do you like ketchup? Client: How about pickles? Client: . Server: 250 Message accepted for delivery Client: QUIT Server: 221 example.com closing connection SMTP is in-band because the control messages, such as "HELO" and "MAIL FROM", a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom (standard)
The name Atom applies to a pair of related Web standards. The Atom Syndication Format is an XML language used for web feeds, while the Atom Publishing Protocol (AtomPub or APP) is a simple HTTP-based protocol for creating and updating web resources. Web feeds allow software programs to check for updates published on a website. To provide a web feed, the site owner may use specialized software (such as a content management system) that publishes a list (or "feed") of recent articles or content in a standardized, machine-readable format. The feed can then be downloaded by programs that use it, like websites that syndicate content from the feed, or by feed reader programs that allow internet users to subscribe to feeds and view their content. A feed contains entries, which may be headlines, full-text articles, excerpts, summaries or links to content on a website along with various metadata. The Atom format was developed as an alternative to RSS. Ben Trott, an advocate of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth Throttling
Bandwidth throttling consists in the intentional limitation of the communication speed (bytes or kilobytes per second) of the ingoing (received) data and/or in the limitation of the speed of outgoing (sent) data in a network node or in a network device. The data speed and rendering may be limited depending on various parameters and conditions. Overview Limiting the speed of data sent by a data originator (a client computer or a server computer) is much more efficient than limiting the speed in an intermediate network device between client and server because while in the first case usually no network packets are lost, in the second case network packets can be lost / discarded whenever ingoing data speed overcomes the bandwidth limit or the capacity of device and data packets cannot be temporarily stored in a buffer queue (because it is full or it does not exist); the usage of such a buffer queue is to absorb the peaks of incoming data for very short time lapse. In the second cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middleware Analyst
Middleware analysts are computer software engineers with a specialization in products that connect two different computer systems together. These products can be open-source or proprietary. As the term implies, the software, tools, and technologies used by Middleware analysts sit "in-the-middle", between two or more systems; the purpose being to enable two systems to communicate and share information. Roles and Responsibilities Middleware analysts look at the system of systems. They solve technical problems which involve large scale inter-disciplinary objectives with multiple, heterogeneous, distributed systems that are embedded in networks at multiple levels. Middleware analysts hold and maintain proficiency in middleware technologies. Middleware is computer software that connects software components or applications. A central theme in most middleware analyst roles is being able to articulate why Service Oriented Architecture ( SOA) is important to the business. Best practices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Client–server Model
The client–server model 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 usually does not share any of its resources, but it requests content or service from a server. 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 and server role The "client–server" characteristic describes the relationship of cooperating programs in an application. The server component provides a function or service to one or many clients, which initiate requests for s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loose Coupling
In computing and systems design, a loosely coupled system is one # in which components are weakly associated (have breakable relationships) with each other, and thus changes in one component least affect existence or performance of another component. # in which each of its components has, or makes use of, little or no knowledge of the definitions of other separate components. Subareas include the coupling of classes, interfaces, data, and services. Loose coupling is the opposite of tight coupling. Advantages and disadvantages Components in a loosely coupled system can be replaced with alternative implementations that provide the same services. Components in a loosely coupled system are less constrained to the same platform, language, operating system, or build environment. If systems are decoupled in time, it is difficult to also provide transactional integrity; additional coordination protocols are required. Data replication across different systems provides loose coupling (i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
