|
Ethernet Multicast Address
A multicast address is a logical identifier for a group of hosts in a computer network that are available to process datagrams or frames intended to be multicast for a designated network service. Multicast addressing can be used in the link layer (layer 2 in the OSI model), such as Ethernet multicast, and at the internet layer (layer 3 for OSI) for Internet Protocol Version 4 (IPv4) or Version 6 (IPv6) multicast. IPv4 IPv4 multicast addresses are defined by the most-significant bit pattern of ''1110''. This originates from the classful network design of the early Internet when this group of addresses was designated as ''Class D''. The CIDR notation for this group is . The group includes the addresses from to . The address range is divided into blocks each assigned a specific purpose or behavior. ;Local subnetwork :Addresses in the range of to are individually assigned by IANA and designated for multicasting on the local subnetwork only. For example, the Routing Information ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Host (network)
A network host is a computer or other device connected to a computer network. A host may work as a server offering information resources, services, and applications to users or other hosts on the network. Hosts are assigned at least one network address. A computer participating in networks that use the Internet protocol suite may also be called an IP host. Specifically, computers participating in the Internet are called Internet hosts. Internet hosts and other IP hosts have one or more IP addresses assigned to their network interfaces. The addresses are configured either manually by an administrator, automatically at startup by means of the Dynamic Host Configuration Protocol (DHCP), or by stateless address autoconfiguration methods. Network hosts that participate in applications that use the client–server model of computing are classified as server or client systems. Network hosts may also function as nodes in peer-to-peer applications, in which all nodes share and consum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cisco
Cisco Systems, Inc. (using the trademark Cisco) is an American multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, software, telecommunications equipment and other high-technology services and products. Cisco specializes in specific tech markets, such as the Internet of things (IoT), domain security, videoconferencing, and energy management with products including Webex, OpenDNS, Jabber, Duo Security, Silicon One, and Jasper. Cisco Systems was founded in December 1984 by Leonard Bosack and Sandy Lerner, two Stanford University computer scientists who had been instrumental in connecting computers at Stanford. They pioneered the concept of a local area network (LAN) being used to connect distant computers over a multiprotocol router system. The company went public in 1990 and, by the end of the dot-com bubble in 2000, had a market capitali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IP Multicast
IP multicast is a method of sending Internet Protocol (IP) datagrams to a group of interested receivers in a single transmission. It is the IP-specific form of multicast and is used for streaming media and other network applications. It uses specially reserved multicast address blocks in IPv4 and IPv6. Protocols associated with IP multicast include Internet Group Management Protocol, Protocol Independent Multicast and Multicast VLAN Registration. IGMP snooping is used to manage IP multicast traffic on layer-2 networks. IP multicast is described in . IP multicast was first standardized in 1986. Its specifications have been augmented in to include group management and in to include administratively scoped addresses. Technical description IP multicast is a technique for one-to-many and many-to-many real-time communication over an IP infrastructure in a network. It scales to a larger receiver population by requiring neither prior knowledge of a receiver's identity nor prior k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IGMP Snooping
IGMP snooping is the process of listening to Internet Group Management Protocol (IGMP) network traffic to control delivery of IP multicasts. Network switches with IGMP snooping listen in on the IGMP conversation between hosts and routers and maintain a map of which links need which IP multicast transmission. Multicasts may be filtered from the links which do not need them, conserving bandwidth on those links. IGMP snooping is described in an informational IETF RFC but affects bridging operations, the purview of the IEEE. Because of a lack of an authoritative standard, the process may operate differently on different equipment. Purpose A switch will, by default, flood multicast traffic to all the ports in a broadcast domain (or the VLAN equivalent). Multicast can cause unnecessary load on host devices by requiring them to process packets they have not solicited. When purposefully exploited, this can form the basis of a denial-of-service attack. IGMP snooping is designed to p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IETF
The Internet Engineering Task Force (IETF) is a standards organization for the Internet standard, Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and all its participants are volunteers. Their work is usually funded by employers or other sponsors. The IETF was initially supported by the federal government of the United States but since 1993 has operated under the auspices of the Internet Society, a non-profit organization with local chapters around the world. Organization There is no membership in the IETF. Anyone can participate by signing up to a working group mailing list, or registering for an IETF meeting. The IETF operates in a bottom-up task creation mode, largely driven by working groups. Each working group normally has appointed two co-chairs (occasionally three); a charter that describes its focus; and what it is expected to produce, and when. It is open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octet (computing)
The octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term '' byte'' might be ambiguous, as the byte has historically been used for storage units of a variety of sizes. The term ''octad(e)'' for eight bits is no longer common. Definition The international standard IEC 60027-2, chapter 3.8.2, states that a byte is an octet of bits. However, the unit byte has historically been platform-dependent and has represented various storage sizes in the history of computing. Due to the influence of several major computer architectures and product lines, the byte became overwhelmingly associated with eight bits. This meaning of ''byte'' is codified in such standards as ISO/IEC 80000-13. While ''byte'' and ''octet'' are often used synonymously, those working with certain legacy systems are careful to avoid ambiguity. Octets can be represented using number systems of varying bases such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomous System Number
An autonomous system (AS) is a collection of connected Internet Protocol (IP) routing prefixes under the control of one or more network operators on behalf of a single administrative entity or domain, that presents a common and clearly defined routing policy to the Internet. Each AS is assigned an autonomous system number (ASN), for use in Border Gateway Protocol (BGP) routing. Autonomous System Numbers are assigned to local Internet registries (LIRs) and end-user organizations by their respective regional Internet registries (RIRs), which in turn receive blocks of ASNs for reassignment from the Internet Assigned Numbers Authority (IANA). The IANA also maintains a registry of ASNs which are reserved for private use (and should therefore not be announced to the global Internet). Originally, the definition required control by a single entity, typically an Internet service provider (ISP) or a very large organization with independent connections to multiple networks, that adhered to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source-specific Multicast
Source-specific multicast (SSM) is a method of delivering multicast packets in which the only packets that are delivered to a receiver are those originating from a specific source address requested by the receiver. By so limiting the source, SSM reduces demands on the network and improves security. SSM requires that the receiver specify the source address and explicitly excludes the use of the (*,G) join for all multicast groups in RFC 3376, which is possible only in IPv4's IGMPv3 and IPv6's MLDv2. Any-source multicast (as counterexample) Source-specific multicast is best understood in contrast to any-source multicast (ASM). In the ASM service model a receiver expresses interest in traffic ''to'' a multicast address. The multicast network must # discover all multicast sources sending to that address, and # route data from all sources to all interested receivers. This behavior is particularly well suited to groupware applications where # all participants in the group want to b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Description Protocol
The Session Description Protocol (SDP) is a format for describing multimedia communication sessions for the purposes of announcement and invitation. Its predominant use is in support of streaming media applications, such as voice over IP (VoIP) and video conferencing. SDP does not deliver any media streams itself but is used between endpoints for negotiation of network metrics, media types, and other associated properties. The set of properties and parameters is called a ''session profile''. SDP is extensible for the support of new media types and formats. SDP was originally a component of the Session Announcement Protocol (SAP), but found other uses in conjunction with the Real-time Transport Protocol (RTP), the Real-time Streaming Protocol (RTSP), Session Initiation Protocol (SIP), and as a standalone protocol for describing multicast sessions. The IETF published the original specification as a Proposed Standard in April 1998 (RFC 2327). Revised specifications were rele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Announcement Protocol
The Session Announcement Protocol (SAP) is an experimental protocol for advertising multicast session information. SAP typically uses Session Description Protocol (SDP) as the format for Real-time Transport Protocol (RTP) session descriptions. Announcement data is sent using IP multicast and the User Datagram Protocol (UDP). Under SAP, senders periodically transmit SDP descriptions to a well-known multicast address and port number (9875). A listening application constructs a guide of all advertised multicast sessions. SAP was published by the IETF as RFC 2974. Announcement interval The announcement interval is cooperatively modulated such that all SAP announcements in the multicast delivery scope, by default, consume 4000 bits per second. Regardless, the maximum announce interval is 300 seconds (5 minutes). Announcements automatically expire after 10 times the announcement interval or one hour, whichever is greater. Announcements may also be explicitly withdrawn by the original is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Time Protocol
The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-Network latency, latency data networks. In operation since before 1985, NTP is one of the oldest Internet protocols in current use. NTP was designed by David L. Mills of the University of Delaware. NTP is intended to synchronize participating computers to within a few milliseconds of Coordinated Universal Time (UTC). It uses the intersection algorithm, a modified version of Marzullo's algorithm, to select accurate time servers and is designed to mitigate the effects of variable network latency. NTP can usually maintain time to within tens of milliseconds over the public Internet, and can achieve better than one millisecond accuracy in local area networks under ideal conditions. Asymmetric Routing, routes and network congestion can cause errors of 100 ms or more. The protocol is usually described in terms of a client–server model, bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicast DNS
Multicast DNS (mDNS) is a computer networking protocol that resolves hostnames to IP addresses within small networks that do not include a local name server. It is a Zero-configuration_networking#Name_service_discovery, zero-configuration service, using essentially the same programming interfaces, packet formats and operating semantics as unicast Domain Name System (DNS). It was designed to work as either a stand-alone protocol or compatible with standard DNS servers. It uses IP multicast User Datagram Protocol (UDP) packets and is implemented by the Apple Bonjour (software), Bonjour and open-source Avahi (software), Avahi software packages, included in most Linux distributions. Although the Windows 10 implementation was limited to discovering networked printers, subsequent releases resolved hostnames as well. mDNS can work in conjunction with DNS Service Discovery (DNS-SD), a companion zero-configuration networking technique specified separately in . History Multicast DNS w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
