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Type–length–value
Within communication protocols, TLV (type-length-value or tag-length-value) is an encoding scheme used for optional informational elements in a certain protocol. A TLV-encoded data stream contains code related to the record type, the record value's length, and finally the value itself. Details The type and length are fixed in size (typically 1–4 bytes), and the value field is of variable size. These fields are used as follows: ;Type: A binary code, often simply alphanumeric, which indicates the kind of field that this part of the message represents; ;Length: The size of the value field (typically in bytes); ;Value: Variable-sized series of bytes which contains data for this part of the message. Some advantages of using a TLV representation data system solution are: * TLV sequences are easily searched using generalized parsing functions; * New message elements which are received at an older node can be safely skipped and the rest of the message can be parsed. This is similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Media Redundancy Protocol
Media Redundancy Protocol (MRP) is a data network protocol standardized by the International Electrotechnical Commission as IEC 62439-2. It allows rings of Ethernet switches to overcome any single failure with recovery time much faster than achievable with Spanning Tree Protocol. It is suitable to most industrial Ethernet applications. Properties MRP operates at the data link layer (OSI Layer 2) of Ethernet switches and is a direct evolution of the HiPER-Ring protocol developed by Hirschmann in 1998. Hirschmann is now owned by Belden. MRP is supported by several commercial industrial Ethernet switches. In an MRP ring, the ring manager is named Media Redundancy Manager (MRM), while ring clients are named Media Redundancy Clients (MRCs). MRM and MRC ring ports support three statuses: disabled, blocked, and forwarding. Disabled ring ports drop all the received frames. Blocked ring ports drop all the received frames except the MRP control frames. Forwarding ring ports forward a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Host Configuration Protocol
The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) networks for automatically assigning IP addresses and other communication parameters to devices connected to the network using a client–server architecture. The technology eliminates the need for individually configuring network devices manually, and consists of two network components, a centrally installed network DHCP server and client instances of the protocol stack on each computer or device. When connected to the network, and periodically thereafter, a client requests a set of parameters from the server using DHCP. DHCP can be implemented on networks ranging in size from residential networks to large campus networks and regional ISP networks. Many routers and residential gateways have DHCP server capability. Most residential network routers receive a unique IP address within the ISP network. Within a local network, a DHCP server assigns a local IP address to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interchange File Format
Interchange File Format (IFF), is a generic container file format originally introduced by Electronic Arts in 1985 (in cooperation with Commodore) in order to facilitate transfer of data between software produced by different companies. IFF files do not have any standard extension. On many systems that generate IFF files, file extensions are not important (the OS stores file format metadata separately from the file name). An .iff extension is commonly used for ILBM format files, which use the IFF container format. Resource Interchange File Format is a format developed by Microsoft and IBM in 1991 that is based on IFF, except the byte order has been changed to little-endian to match the x86 processor architecture. Apple's AIFF is a big-endian audio file format developed from IFF. The TIFF image file format is unrelated. Structure An IFF file is built up from chunks. Each chunk begins with what the specification calls a "Type ID" (what the Macintosh called an OSType, and Windo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertext Transfer Protocol
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access, for example by a mouse click or by tapping the screen in a web browser. Development of HTTP was initiated by Tim Berners-Lee at CERN in 1989 and summarized in a simple document describing the behavior of a client and a server using the first HTTP protocol version that was named 0.9. That first version of HTTP protocol soon evolved into a more elaborated version that was the first draft toward a far future version 1.0. Development of early HTTP Requests for Comments (RFCs) started a few years later and it was a coordinated effort by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C), with work later moving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
File Transfer Protocol
The File Transfer Protocol (FTP) is a standard communication protocol used for the transfer of computer files from a server to a client on a computer network. FTP is built on a client–server model architecture using separate control and data connections between the client and the server. FTP users may authenticate themselves with a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that protects the username and password, and encrypts the content, FTP is often secured with SSL/TLS (FTPS) or replaced with SSH File Transfer Protocol (SFTP). The first FTP client applications were command-line programs developed before operating systems had graphical user interfaces, and are still shipped with most Windows, Unix, and Linux operating systems. Many dedicated FTP clients and automation utilities have since been developed for desktops, servers, mobile devices, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Mail Transfer Protocol
The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typically use SMTP only for sending messages to a mail server for relaying, and typically submit outgoing email to the mail server on port 587 or 465 per . For retrieving messages, IMAP (which replaced the older POP3) is standard, but proprietary servers also often implement proprietary protocols, e.g., Exchange ActiveSync. SMTP's origins began in 1980, building on concepts implemented on the ARPANET since 1971. It has been updated, modified and extended multiple times. The protocol version in common use today has extensible structure with various extensions for authentication, encryption, binary data transfer, and internationalized email addresses. SMTP servers commonly use the Transmission Control Protocol on port number 25 (for plaintext) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post Office Protocol
In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server. POP version 3 (POP3) is the version in common use, and along with IMAP the most common protocols for email retrieval. Purpose The Post Office Protocol provides access via an Internet Protocol (IP) network for a user client application to a mailbox (''maildrop'') maintained on a mail server. The protocol supports download and delete operations for messages. POP3 clients connect, retrieve all messages, store them on the client computer, and finally delete them from the server. This design of POP and its procedures was driven by the need of users having only temporary Internet connections, such as dial-up access, allowing these users to retrieve e-mail when connected, and subsequently to view and manipulate the retrieved messages when offline. POP3 clients also have an option to leave mail on the server after download. By contr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Initiation Protocol
The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice, video and messaging applications. SIP is used in Internet telephony, in private IP telephone systems, as well as mobile phone calling over LTE (VoLTE). The protocol defines the specific format of messages exchanged and the sequence of communications for cooperation of the participants. SIP is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP). A call established with SIP may consist of multiple media streams, but no separate streams are required for applications, such as text messaging, that exchange data as payload in the SIP message. SIP works in conjunction with several other protocols that specify and carry the session media. Most commonly, media type and parameter negotiation and media setup are performed with the Session Description ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication 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 synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses pre-determined for that particular situation. The specified behavior is typically independent of how it is to be implemented. Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard. A programming language describes the same for computations, so there is a close analogy between protocols and programming languages: ''protocols are to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
User Datagram Protocol
In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages (transported as datagrams in packets) to other hosts on an Internet Protocol (IP) network. Within an IP network, UDP does not require prior communication to set up communication channels or data paths. UDP uses a simple connectionless communication model with a minimum of protocol mechanisms. UDP provides checksums for data integrity, and port numbers for addressing different functions at the source and destination of the datagram. It has no handshaking dialogues, and thus exposes the user's program to any unreliability of the underlying network; there is no guarantee of delivery, ordering, or duplicate protection. If error-correction facilities are needed at the network interface level, an application may instead use Transmission Control Protocol (TCP) or Stream Control Transmission Protocol (SCTP) which are designed for this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basic Encoding Rules
X.690 is an ITU-T standard specifying several ASN.1 encoding formats: * Basic Encoding Rules (BER) * Canonical Encoding Rules (CER) * Distinguished Encoding Rules (DER) The Basic Encoding Rules (BER) were the original rules laid out by the ASN.1 standard for encoding data into a binary format. The rules, collectively referred to as a ''transfer syntax'' in ASN.1 parlance, specify the exact octets (8-bit bytes) used to encode data. X.680 defines a syntax for declaring data types, for example: booleans, numbers, strings, and compound structures. Each type definition also includes an identifying number. X.680 defines several ''primitive'' data types, for example: BooleanType, IntegerType, OctetStringType. (ASN.1 also provides for ''constructed'' types built from other types.) Types are associated with a ''class''. For example, the primitive types are part of the ''universal'' class. The three other classes (''application'', ''private'', and ''context-specific'') are essentiall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distinguished Encoding Rules
X.690 is an ITU-T standard specifying several ASN.1 encoding formats: * Basic Encoding Rules (BER) * Canonical Encoding Rules (CER) * Distinguished Encoding Rules (DER) The Basic Encoding Rules (BER) were the original rules laid out by the ASN.1 standard for encoding data into a binary format. The rules, collectively referred to as a ''transfer syntax'' in ASN.1 parlance, specify the exact octets (8-bit bytes) used to encode data. X.680 defines a syntax for declaring data types, for example: booleans, numbers, strings, and compound structures. Each type definition also includes an identifying number. X.680 defines several ''primitive'' data types, for example: BooleanType, IntegerType, OctetStringType. (ASN.1 also provides for ''constructed'' types built from other types.) Types are associated with a ''class''. For example, the primitive types are part of the ''universal'' class. The three other classes (''application'', ''private'', and ''context-specific'') are essential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
