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Reverse-path Forwarding
Reverse-path forwarding (RPF) is a technique used in modern routers for the purposes of ensuring loop-free forwarding of multicast packets in multicast routing and to help prevent IP address spoofing in unicast routing. In standard unicast IP routing, the router forwards the packet away from the source to make progress along the distribution tree and prevent routing loops. In contrast, the router's multicast forwarding state runs more logically by organizing tables based on the reverse path, from the receiver back to the root of the distribution tree at the source of the multicast. This approach is known as reverse-path forwarding. Multicast RPF Multicast RPF, typically denoted simply as RPF, is used in conjunction with a multicast routing protocol such as Multicast Source Discovery Protocol or Protocol Independent Multicast to ensure loop-free forwarding of multicast packets. In multicast routing, the decision to forward traffic is based upon source address and not on desti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Router (computing)
A router is a computer and networking device that Packet forwarding, forwards data packets between computer networks, including internetworks such as the global Internet. Routers perform the "traffic directing" functions on the Internet. A router is connected to two or more data lines from different IP networks. When a data packet comes in on a line, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Data packets are forwarded from one router to another through an internetwork until it reaches its destination Node (networking), node. The most familiar type of Internet Protocol, IP routers are Residential gateway, home and small office routers that forward IP packet (other), IP packets between the home computers and the Internet. More sophisticated routers, such as enterprise routers, conne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Multicast
In computer networking, multicast is a type of 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 differs from 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 im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Multicast Routing
Multicast routing is one of the routing protocols in IP networking.CISCO Security Research & Operations- 3 June 201Understanding Unicast Reverse Path Forwarding , Cisco -unicast-reverse-path-forwarding/ref> There are several multicast routing protocols supporting communications where data transmission is addressed to a group of destination computers simultaneously: Multicast Source Discovery Protocol, Multicast BGP, Protocol Independent Multicast. Overview Multicast routing is a method of transmitting to all subscribers registered in a group by one transmission unlike unicast routing (i.e. OSPF, RIP) which transmits 1: 1 necessary data.CISCO Security Research & Operations- 3 June 201IP Multicast Routing Technology Overview , Cisco IP Multicast Routing Technology Overview/ref> To implement the multicast routing, Internet Group Management Protocol (IGMP) and a multicast routing protocol (Reverse-path forwarding, PIM-SM) for registration subscriber grouping and control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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IP Address Spoofing
In computer networking, IP address spoofing or IP spoofing is the creation of Internet Protocol (IP) packets with a false source IP address, for the purpose of impersonating another computing system. Background The basic protocol for sending data over the Internet network and many other computer networks is the Internet Protocol (IP). The protocol specifies that each IP packet must have a header which contains (among other things) the IP address of the sender of the packet. The source IP address is normally the address that the packet was sent from, but the sender's address in the header can be altered, so that to the recipient it appears that the packet came from another source. The protocol requires the receiving computer to send back a response to the source IP address therefore spoofing is mainly used when the sender can anticipate the network response or does not care about the response. The source IP address provides only limited information about the sender. It may pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Unicast
Unicast is data transmission from a single sender (red) to a single receiver (green). Other devices on the network (yellow) do not participate in the communication. In computer networking, unicast is a one-to-one transmission from one point in the network to another point; that is, one sender and one receiver, each identified by a network address. Unicast is in contrast to multicast and broadcast which are one-to-many transmissions. Internet Protocol unicast delivery methods such as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are typically used. See also * Anycast * Broadcast, unknown-unicast and multicast traffic * IP address * IP multicast * Routing Routing is the process of selecting a path for traffic in a Network theory, network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched ... References External links * Internet archit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Juniper Networks
Juniper Networks, Inc. is an American multinational corporation headquartered in Sunnyvale, California. The company develops and markets networking products, including Router (computing), routers, Network switch, switches, network management software, network security products, and software-defined networking technology. The company was founded in 1996 by Pradeep Sindhu, with Scott Kriens as the first CEO, who remained until September 2008. Kriens has been credited with much of Juniper's early market success. It received several rounds of funding from venture capitalists and telecommunications companies before Initial public offering, going public in 1999. Juniper grew to $673 million in annual revenues by 2000. By 2001 it had a 37% share of the core routers market, challenging Cisco Systems, Cisco's once-dominant market-share. It grew to US$4 billion in revenues by 2004 and $4.63 billion in 2014. Juniper appointed Kevin Johnson (executive), Kevin Johnson as CEO in 2008, Shaygan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Multicast Source Discovery Protocol
Multicast Source Discovery Protocol (MSDP) is a Protocol Independent Multicast (PIM) family multicast routing protocol defined by Experimental RFC 3618. Despite becoming the IPv4 de facto standard for inter-domain multicast, development of the protocol stopped in 2006 and it was decided by the authors not to proceed with making it a proposed standard. MSDP interconnects multiple IPv4 PIM Sparse-Mode (PIM-SM) domains which enables PIM-SM to have Rendezvous Point (RP) redundancy and inter-domain multicasting RFC 4611. MSDP uses TCP as its transport protocol. Each multicast tree needs to have its own RP. All of the RPs are peers (directly or through other MSDP peers). Messages contain the sender (source) address and the multicast group address (S,G). If an RP on its own domain receives a message, it determines if there are listeners for this group. If listeners exist, it triggers a PIM join into the source domain towards the data source. In a peering relationship, one MSDP pee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Protocol Independent Multicast
image:IGMP basic architecture.png, 400px, Example of a multicast network architecture Protocol-Independent Multicast (PIM) is a family of multicast routing protocols for Internet Protocol (IP) networks that provide Point-to-multipoint communication, one-to-many and many-to-many distribution of data over a LAN, Wide area network, WAN or the Internet. It is termed ''protocol-independent'' because PIM does not include its own network topology, topology discovery mechanism, but instead uses routing information supplied by other routing protocols. PIM is not dependent on a specific unicast routing protocol; it can make use of any unicast routing protocol in use on the network. PIM does not build its own routing tables. PIM uses the unicast routing table for reverse-path forwarding. There are four variants of PIM: * PIM Sparse Mode (PIM-SM) explicitly builds unidirectional shared trees rooted at a ''rendezvous point'' (RP) per group, and optionally creates shortest-path trees per sourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Routing Loop
A routing loop is a common problem with various types of networks, particularly computer networks. They are formed when an error occurs in the operation of the routing algorithm, and as a result, in a group of nodes, the path to a particular destination forms a loop. In the simplest version, a routing loop of size two, node A thinks that the path to some destination (call it C) is through its neighbouring node, node B. At the same time, node B thinks that the path to C starts at node A. Thus, whenever traffic for C arrives at either A or B, it will loop endlessly between A and B, unless some mechanism exists to prevent that behaviour. How a routing loop can form For example, in this illustration, node A is transmitting data to node C via node B. If the link between nodes B and C goes down and B has not yet informed node A about the breakage, node A transmits the data to node B assuming that the link A-B-C is operational and of lowest cost. Node B knows of the broken link and tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Time To Live
Time to live (TTL) or hop limit is a mechanism which limits the lifespan or lifetime of data in a computer or network. TTL may be implemented as a counter (digital), counter or timestamp attached to or embedded in the data. Once the prescribed event count or timespan has elapsed, data is discarded or revalidated. In computer networking, TTL prevents a data packet from circulating indefinitely. In computing applications, TTL is commonly used to improve the performance and manage the cache (computing), caching of data. Description The original DARPA Internet Protocol's Request for Comment, RFC describes TTL as: IP packets Under the Internet Protocol, TTL is an 8-bit field. In the IPv4 header, TTL is the 9th octet (computing), octet of 20. In the IPv6 header, it is the 8th octet of 40. The maximum TTL value is 255, the maximum value of a single octet. A recommended initial value is 64. The time-to-live value can be thought of as an upper bound on the time that an IP datagram c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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DDoS
In computing, a denial-of-service attack (DoS attack) is a cyberattack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to a network. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled. The range of attacks varies widely, spanning from inundating a server with millions of requests to slow its performance, overwhelming a server with a substantial amount of invalid data, to submitting requests with an illegitimate IP address. In a distributed denial-of-service attack (DDoS attack), the incoming traffic flooding the victim originates from many different sources. More sophisticated strategies are required to mitigate this type of attack; simply attempting to block a single source is insuffic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Cisco Systems
Cisco Systems, Inc. (using the trademark Cisco) is an American multinational corporation, multinational digital communications technology conglomerate (company), 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), internet domain, domain security, videoconferencing, and energy management with List of Cisco products, products including Webex, OpenDNS, XMPP, Jabber, Duo Security, Silicon One, and Cisco Jasper, 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 (computing), route ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |