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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] |
TCP/IP
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP). In the development of this networking model, early versions of it were known as the Department of Defense (DoD) model because the research and development were funded by the United States Department of Defense through DARPA. The Internet protocol suite provides end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received. This functionality is organized into four abstraction layers, which classify all related protocols according to each protocol's scope of networking. An implementation of the layers for a particular application forms a protocol stack. From lowest to high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sliding Window Protocol
A sliding window protocol is a feature of packet-based data transmission protocols. Sliding window protocols are used where reliable in-order delivery of packets is required, such as in the data link layer (OSI layer 2) as well as in the Transmission Control Protocol (TCP). They are also used to improve efficiency when the channel may include high latency. Packet-based systems are based on the idea of sending a batch of data, the ''packet'', along with additional data that allows the receiver to ensure it was received correctly, perhaps a checksum. The paradigm is similar to a window sliding sideways to allow entry of fresh packets and reject the ones that have already been acknowledged. When the receiver verifies the data, it sends an acknowledgment signal, or "ACK", back to the sender to indicate it can send the next packet. In a simple automatic repeat request protocol (ARQ), the sender stops after every packet and waits for the receiver to ACK. This ensures packets arrive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larry L
Larry is a masculine given name in English, derived from Lawrence or Laurence. It can be a shortened form of those names. Larry may refer to the following: People Arts and entertainment * Larry D. Alexander, American artist/writer *Larry Boone, American country singer * Larry Collins, American musician, member of the rockabilly sibling duo The Collins Kids *Larry David (born 1947), Emmy-winning American actor, writer, comedian, producer and film director *Larry Emdur, Australian TV host *Larry Feign, American cartoonist working in Hong Kong *Larry Fine, of the Three Stooges * Larry Gates, American actor *Larry Gatlin, American country singer *Larry Gelbart (1928–2009), American screenwriter, playwright, director and author *Larry Graham, founder of American funk band Graham Central Station *Larry Hagman, American actor, best known for the TV series ''I Dream of Jeannie'' and ''Dallas'' *Larry Henley (1937–2014), American singer and songwriter, member of The Newbeats *Larry H ... [...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] |
Bandwidth (computing)
In computing, bandwidth is the maximum rate of data transfer across a given path. Bandwidth may be characterized as network bandwidth, data bandwidth, or digital bandwidth. This definition of ''bandwidth'' is in contrast to the field of signal processing, wireless communications, modem data transmission, digital communications, and electronics, in which ''bandwidth'' is used to refer to analog signal bandwidth measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power. The actual bit rate that can be achieved depends not only on the signal bandwidth but also on the noise on the channel. Network capacity The term ''bandwidth'' sometimes defines the net bit rate 'peak bit rate', 'information rate,' or physical layer 'useful bit rate', channel capacity, or the maximum throughput of a logical or physical communication path in a digital communication system. For example, bandwidth test ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latency (engineering)
Latency, from a general point of view, is a time delay between the cause and the effect of some physical change in the system being observed. Lag, as it is known in gaming circles, refers to the latency between the input to a simulation and the visual or auditory response, often occurring because of network delay in online games. Latency is physically a consequence of the limited velocity at which any physical interaction can propagate. The magnitude of this velocity is always less than or equal to the speed of light. Therefore, every physical system with any physical separation (distance) between cause and effect will experience some sort of latency, regardless of the nature of the stimulation at which it has been exposed to. The precise definition of latency depends on the system being observed or the nature of the simulation. In communications, the lower limit of latency is determined by the medium being used to transfer information. In reliable two-way communication syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ACK (TCP)
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. Applic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TCP Delayed Acknowledgment
TCP delayed acknowledgment is a technique used by some implementations of the Transmission Control Protocol in an effort to improve network performance. In essence, several ACK responses may be combined into a single response, reducing protocol overhead. However, in some circumstances, the technique can reduce application performance. Method and advantages As described in RFC 1122, a host may delay sending an ACK response by up to 500 ms. Additionally, with a stream of full-sized incoming segments, ACK responses should be sent for every second segment. Delayed ACKs can give the application the opportunity to update the TCP receive window and also possibly to send an immediate response along with the ACK. For certain protocols such as Telnet, delayed ACKs can reduce the number of responses sent by the server by a factor of 3, by combining the ACK, window update and the response data into one segment. Problems The additional wait time introduced by the delayed ACK can cause further ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maximum Segment Size
The maximum segment size (MSS) is a parameter of the ''options'' field of the TCP header that specifies the largest amount of data, specified in bytes, that a computer or communications device can receive in a single TCP segment. It does not count the TCP header or the IP header (unlike, for example, the MTU for IP datagrams). The IP datagram containing a TCP segment may be self-contained within a single packet, or it may be reconstructed from several fragmented pieces; either way, the MSS limit applies to the total amount of data contained in the final, reconstructed TCP segment. To avoid fragmentation in the IP layer, a host must specify the maximum segment size as equal to the largest IP datagram that the host can handle minus the IP and TCP header sizes. Therefore, IPv4 hosts are required to be able to handle an MSS of 536 octets (= 576 - 20 - 20) and IPv6 hosts are required to be able to handle an MSS of 1220 octets (= 1280 - 40 - 20). Small MSS values will reduce or elim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ford Aerospace
Ford Aerospace was the aerospace and defense division of Ford Motor Company. It was based in Dearborn, Michigan and was active from 1956 (originally as Philco and then Philco Ford) through 1990, when it was sold to the Loral Corporation. Major divisions were located in Palo Alto CA (Space Systems Division), San Jose CA (Western Development Laboratories) and Newport Beach (Aeronutronic Division). Other operations were located in a number of other states around the United States. History The company was established in 1956. It was renamed to "Ford Aerospace and Communications Corporation" in 1976, and then to "Ford Aerospace Corporation" in 1988. The Engineering and Research Center campus was located on Jamboree Road at Ford Road, overlooking the Santa Catalina Strait of the Pacific Ocean in Newport Beach. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congestion Collapse
Network congestion in data networking and queueing theory is the reduced quality of service that occurs when a network node or link is carrying more data than it can handle. Typical effects include queueing delay, packet loss or the blocking of new connections. A consequence of congestion is that an incremental increase in offered load leads either only to a small increase or even a decrease in network throughput. Network protocols that use aggressive retransmissions to compensate for packet loss due to congestion can increase congestion, even after the initial load has been reduced to a level that would not normally have induced network congestion. Such networks exhibit two stable states under the same level of load. The stable state with low throughput is known as congestive collapse. Networks use congestion control and congestion avoidance techniques to try to avoid collapse. These include: exponential backoff in protocols such as CSMA/CA in 802.11 and the similar CSMA/CD in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telnet
Telnet is an application protocol used on the Internet or local area network to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. User data is interspersed in-band with Telnet control information in an 8-bit byte oriented data connection over the Transmission Control Protocol (TCP). Telnet was developed in 1969 beginning with , extended in , and standardized as Internet Engineering Task Force (IETF) Internet Standard STD 8, one of the first Internet standards. The name stands for " teletype network". Historically, Telnet provided access to a command-line interface on a remote host. However, because of serious security concerns when using Telnet over an open network such as the Internet, its use for this purpose has waned significantly in favor of SSH. The term ''telnet'' is also used to refer to the software that implements the client part of the protocol. Telnet client applications are available for virtually all c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
