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Stream Control Transmission Protocol
The Stream Control Transmission Protocol (SCTP) is a computer networking communications protocol in the transport layer of the Internet protocol suite. Originally intended for Signaling System 7 (SS7) message transport in telecommunication, the protocol provides the message-oriented feature of the User Datagram Protocol (UDP), while ensuring reliable, in-sequence transport of messages with congestion control like the Transmission Control Protocol (TCP). Unlike UDP and TCP, the protocol supports multihoming and redundant paths to increase resilience and reliability. SCTP is standardized by the Internet Engineering Task Force (IETF) in . The SCTP reference implementation was released as part of FreeBSD version 7, and has since been widely ported to other platforms. Formal oversight The IETF Signaling Transport (SIGTRAN) working group defined the protocol (number 132) in October 2000, and the IETF Transport Area (TSVWG) working group maintains it. defines the protocol. provides an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Networking
A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are made up of telecommunication network technologies, based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topologies. The nodes of a computer network can include personal computers, servers, networking hardware, or other specialised or general-purpose hosts. They are identified by network addresses, and may have hostnames. Hostnames serve as memorable labels for the nodes, rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the transmission medium used to carry signals, bandwidth, communications protocols ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TCP Segment
The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliable, ordered, and error-checked delivery of a stream of octets (bytes) between applications running on hosts communicating via an IP network. Major internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP, which is part of the Transport Layer of the TCP/IP suite. SSL/TLS often runs on top of TCP. TCP is connection-oriented, and a connection between client and server is established before data can be sent. The server must be listening (passive open) for connection requests from clients before a connection is established. Three-way handshake (active open), retransmission, and error detection adds to reliability but lengthens latency. Applicatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer from cellular phones and video game consoles to web servers and supercomputers. The dominant general-purpose personal computer operating system is Microsoft Windows with a market share of around 74.99%. macOS by Apple Inc. is in second place (14.84%), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TCP/IP Stack Fingerprinting
TCP/IP stack fingerprinting is the remote detection of the characteristics of a TCP/IP stack implementation. The combination of parameters may then be used to infer the remote machine's operating system (aka, OS fingerprinting), or incorporated into a device fingerprint. TCP/IP Fingerprint Specifics Certain parameters within the TCP protocol definition are left up to the implementation. Different operating systems, and different versions of the same operating system, set different defaults for these values. By collecting and examining these values, one may differentiate among various operating systems, and implementations of TCP/IP. The TCP/IP fields that may vary include the following: * Initial packet size (16 bits) * Initial TTL (8 bits) * Window size (16 bits) * Max segment size (16 bits) * Window scaling value (8 bits) * "don't fragment" flag (1 bit) * "sackOK" flag (1 bit) * "nop" flag (1 bit) These values may be combined to form a 67-bit signature, or fingerprint, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SYN Flood
A SYN flood is a form of denial-of-service attack in which an attacker rapidly initiates a connection to a server without finalizing the connection. The server has to spend resources waiting for half-opened connections, which can consume enough resources to make the system unresponsive to legitimate traffic. The packet that the attacker sends is the SYN packet, a part of TCP's three-way handshake used to establish a connection. Technical details When a client attempts to start a TCP connection to a server, the client and server exchange a series of messages which normally runs like this: #The client requests a connection by sending a SYN (''synchronize'') message to the server. #The server ''acknowledges'' this request by sending SYN-ACK back to the client. #The client responds with an ACK, and the connection is established. This is called the TCP three-way handshake, and is the foundation for every connection established using the TCP protocol. A SYN flood attack works ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-way Handshake
The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliable, ordered, and error-checked delivery of a stream of octets (bytes) between applications running on hosts communicating via an IP network. Major internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP, which is part of the Transport Layer of the TCP/IP suite. SSL/TLS often runs on top of TCP. TCP is connection-oriented, and a connection between client and server is established before data can be sent. The server must be listening (passive open) for connection requests from clients before a connection is established. Three-way handshake (active open), retransmission, and error detection adds to reliability but lengthens latency. Applica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Handshake (computing)
In computing, a handshake is a signal between two devices or programs, used to, e.g., authenticate, coordinate. An example is the handshaking between a hypervisor and an application in a guest virtual machine. In telecommunications, a handshake is an automated process of negotiation between two participants (example "Alice and Bob") through the exchange of information that establishes the protocols of a communication link at the start of the communication, before full communication begins. The handshaking process usually takes place in order to establish rules for communication when a computer attempts to communicate with another device. Signals are usually exchanged between two devices to establish a communication link. For example, when a computer communicates with another device such as a modem, the two devices will signal each other that they are switched on and ready to work, as well as to agree to which protocols are being used. Handshaking can negotiate parameters that a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heartbeat (computing)
In computer science, a heartbeat is a periodic signal generated by hardware or software to indicate normal operation or to synchronize other parts of a computer system. Heartbeat mechanism is one of the common techniques in mission critical systems for providing high availability and fault tolerance of network services by detecting the network or systems failures of nodes or daemons which belongs to a network cluster—administered by a master server—for the purpose of automatic adaptation and rebalancing of the system by using the remaining redundant nodes on the cluster to take over the load of failed nodes for providing constant services. Usually a heartbeat is sent between machines at a regular interval in the order of seconds; a heartbeat message. If the endpoint does not receive a heartbeat for a time—usually a few heartbeat intervals—the machine that should have sent the heartbeat is assumed to have failed. Heartbeat messages are typically sent non-stop on a perio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SYN Attack
A SYN flood is a form of denial-of-service attack in which an attacker rapidly initiates a connection to a server without finalizing the connection. The server has to spend resources waiting for half-opened connections, which can consume enough resources to make the system unresponsive to legitimate traffic. The packet that the attacker sends is the SYN packet, a part of TCP's three-way handshake used to establish a connection. Technical details When a client attempts to start a TCP connection to a server, the client and server exchange a series of messages which normally runs like this: #The client requests a connection by sending a SYN (''synchronize'') message to the server. #The server ''acknowledges'' this request by sending SYN-ACK back to the client. #The client responds with an ACK, and the connection is established. This is called the TCP three-way handshake, and is the foundation for every connection established using the TCP protocol. A SYN flood attack works ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nagle's Algorithm
Nagle's algorithm is a means of improving the efficiency of TCP/IP networks by reducing the number of packets that need to be sent over the network. It was defined by John Nagle while working for Ford Aerospace. It was published in 1984 as a Request for Comments (RFC) with title ''Congestion Control in IP/TCP Internetworks'' in . The RFC describes what he called the "small-packet problem", where an application repeatedly emits data in small chunks, frequently only 1 byte in size. Since Transmission Control Protocol, TCP packets have a 40-byte header (20 bytes for TCP, 20 bytes for IPv4), this results in a 41-byte packet for 1 byte of useful information, a huge overhead. This situation often occurs in Telnet sessions, where most keypresses generate a single byte of data that is transmitted immediately. Worse, over slow links, many such packets can be in transit at the same time, potentially leading to congestion collapse. Nagle's algorithm works by combining a number of small outg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reliable Server Pooling
Reliable Server Pooling (RSerPool) is a computer protocol framework for management of and access to multiple, coordinated (pooled) servers. RSerPool is an IETF standard, which has been developed by the IETF RSerPool Working Group and documented in RFC 5351, RFC 5352, RFC 5353, RFC 5354, RFC 5355 and RFC 5356. Introduction In the terminology of RSerPool a server is denoted as a Pool Element (PE). In its Pool, it is identified by its Pool Element Identifier (PE ID), a 32-bit number. The PE ID is randomly chosen upon a PE's registration to its pool. The set of all pools is denoted as the Handlespace. In older literature, it may be denoted as Namespace. This denomination has been dropped in order to avoid confusion with the Domain Name System (DNS). Each pool in a handlespace is identified by a unique Pool Handle (PH), which is represented by an arbitrary byte vector. Usually, this is an ASCII or Unicode name of the pool, e.g. "DownloadPool" or "WebServerPool". Each handlespace ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diameter (protocol)
Diameter is an authentication, authorization, and accounting protocol for computer networks. It evolved from the earlier RADIUS protocol. It belongs to the application layer protocols in the internet protocol suite. ''Diameter Applications'' extend the base protocol by adding new commands and/or attributes, such as those for use with the Extensible Authentication Protocol (EAP). Comparison with RADIUS The name is a play on words, derived from the RADIUS protocol, which is the predecessor (a diameter is twice the radius). Diameter is not directly backward compatible but provides an upgrade path for RADIUS. The main features provided by Diameter but lacking in RADIUS are: * Support for SCTP * Capability negotiation * Application layer acknowledgements; Diameter defines failover methods and state machines (RFC 3539) * Extensibility; new commands can be defined * Aligned on 32 bit boundaries Also: Like RADIUS, it is intended to work in both local and roaming AAA situatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
