Gnutella2 , often referred to as G2 , is a peer-to-peer protocol developed mainly by Michael Stokes and released in 2002.
63-421: While inspired by the gnutella protocol, G2 shares little of its design with the exception of its connection handshake and download mechanics. G2 adopts an extensible binary packet format and an entirely new search algorithm . Furthermore, G2 has a related (but significantly different) network topology and an improved metadata system, which helps effectively to reduce fake files, such as viruses , on
126-404: A JE ... (Jump if Equal) instruction in the x86 assembly language will result in a jump if the Z (zero) flag was set by some previous operation. A bit field is distinguished from a bit array in that the latter is used to store a large set of bits indexed by integers and is often wider than any integral type supported by the language. Bit fields, on the other hand, typically fit within
189-476: A Consent Decree to which recording industry plaintiffs and LimeWire had agreed. This event was the likely cause of a notable drop in the size of the network, because, while negotiating the injunction , LimeWire staff had inserted remote-disabling code into the software. As the injunction came into force, users who had installed affected versions (newer than 5.5.10) were cut off from the P2P network . Since LimeWire
252-515: A "cheap publicity stunt " and discounted technical merits. Some still refuse to refer to the network as "Gnutella2", and instead, refer to it as "Mike's Protocol" ("MP"). The Gnutella2 protocol still uses the old "GNUTELLA CONNECT/0.6" handshake string for its connections as defined in the gnutella 0.6 specifications. This backwardly compatible handshake method was criticized by the Gnutella Developers Forum as an attempt to use
315-522: A Leaf has by means of a Query Routing Table , which is filled with single bit entries of hashes of keywords , which the Leaf uploads to the Hub, and which the Hub then combines with all the hash tables its Leaves have sent, it in order to create a version to send to their neighboring Hubs. This allows for Hubs to reduce bandwidth greatly by simply not forwarding queries to Leaves and neighboring Hubs, if
378-454: A commercial file sharing group, abandoned its FastTrack-based peer-to-peer software and released a new client based on the free and open source Gnutella client Gnucleus . The word Gnutella today refers not to any one project or piece of software, but to the open protocol used by the various clients. The name is a portmanteau of GNU and Nutella , the brand name of an Italian hazelnut flavored spread: supposedly, Frankel and Pepper ate
441-467: A few days, the protocol had been reverse engineered , and compatible free and open source clones began to appear. This parallel development of different clients by different groups remains the modus operandi of Gnutella development today. Among the first independent Gnutella pioneers were Gene Kan and Spencer Kimball , who launched the first portal aimed to assemble the open-source community to work on Gnutella and also developed "GNUbile", one of
504-708: A lot of Nutella working on the original project, and intended to license their finished program under the GNU General Public License. Gnutella is not associated with the GNU project or GNU's own peer-to-peer network, GNUnet . On October 26, 2010, the popular Gnutella client LimeWire was ordered shut down by Judge Kimba Wood of the United States District Court for the Southern District of New York when she signed
567-402: A machine word , and the denotation of bits is independent of their numerical index. Bit fields can be used to reduce memory consumption when a program requires a number of integer variables which always will have low values. For example, in many systems, storing an integer value requires two bytes (16-bits) of memory; sometimes the values to be stored actually need only one or two bits. Having
630-485: A number of applications supporting the Gnutella network. The tables do not attempt to give a complete list of Gnutella clients . The tables are limited to clients that can participate in the current Gnutella network. Discontinued project The Gnutella2 protocol (often referred to as G2), despite its name, is not a successor protocol of Gnutella nor related to the original Gnutella project, but rather
693-514: A number of available applications supporting the G2 network. eD2k , OpenNap NEOnet eD2k , BitTorrent Gnutella Gnutella is a peer-to-peer network protocol. Founded in 2000, it was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model. In June 2005, Gnutella's population was 1.81 million computers increasing to over three million nodes by January 2006. In late 2007, it
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#1732787668829756-537: A number of these tiny variables share a bit field allows efficient packaging of data in the memory. In C, native implementation-defined bit fields can be created using int , unsigned int , signed int , _Bool (in C99), _BitInt(N) , unsigned _BitInt(N) (in C23) or other implementation-defined types. In C++, they can be created using any integral or enumeration type; most C compilers also allow this. In this case,
819-455: A pre-existing address list of possibly working nodes shipped with the software, using updated web caches of known nodes (called Gnutella Web Caches ), UDP host caches and, rarely, even IRC . Once connected, the client requests a list of working addresses. The client tries to connect to the nodes it was shipped with, as well as nodes it receives from other clients until it reaches a certain quota. It connects to only that many nodes, locally caching
882-610: A primitive and bit operators: The status register of a processor is a bit field consisting of several flag bits. Each flag bit describes information about the processor's current state. As an example, the status register of the 6502 processor is shown below: These bits are set by the processor following the result of an operation. Certain bits (such as the Carry, Interrupt-disable, and Decimal flags) may be explicitly controlled using set and clear instructions. Additionally, branching instructions are also defined to alter execution based on
945-475: A search is initiated, the node obtains a list of Hubs, if needed, and contacts the Hubs in the list, noting which have been searched, until the list is exhausted or a predefined search limit has been reached. This allows a user to find a popular file easily without loading the network, while, theoretically, maintaining the ability for a user to find a single file located anywhere on the network. Hubs index what files
1008-456: A single bit to the nth position. Most also support the use of the AND operator (&) to isolate the value of one or more bits. If the status-byte from a device is 0x67 and the 5th flag bit indicates data-ready. The mask-byte is 2^5 = 0x20 . ANDing the status-byte 0x67 ( 0110 0111 in binary) with the mask-byte 0x20( 0010 0000 in binary) evaluates to 0x20. This means the flag bit
1071-463: A user disconnects, the client software saves a list of known nodes. This contains the nodes to which the client was connected and the nodes learned from pong packets. The client uses that as its seed list, when it next starts, thus becoming independent of bootstrap services. In practice, this method of searching on the Gnutella network was often unreliable. Each node is a regular computer user; as such, they are constantly connecting and disconnecting, so
1134-473: Is a completely different protocol that forked from the original project and piggybacked on the Gnutella name. A sore point with many Gnutella developers is that the Gnutella2 name conveys an upgrade or superiority, which led to a flame war. Other criticism included the use of the Gnutella network to bootstrap G2 peers and poor documentation of the G2 protocol. Additionally, the more frequent search retries of
1197-475: Is no standard method to inform the sending client that a message was received, and so if the packet is lost, there is no way to know. Because of this, UDP packets in Gnutella2 have a flag to enable a reliability setting. When an UDP packet with enabled reliability flag is received, the client will respond with an acknowledge packet to inform the sending client that their packet arrived at its destination. If
1260-536: Is not supported by many of the "old" gnutella network clients, however, many Gnutella2 clients still also connect to gnutella. Many Gnutella2 proponents claim that this is because of political reasons, while gnutella supporters claim that the drastic changes don't have enough merit to outweigh the cost of deep rewrites. Gnutella2 divides nodes into two groups: Leaves and Hubs. Most Leaves maintain two connections to Hubs, while Hubs accept hundreds of Leaf connections, and an average of 7 connections to other Hubs. When
1323-426: Is possible to manually manipulate bits within a larger word type. In this case, the programmer can set, test, and change the bits in the field using combinations of masking and bitwise operations . Declaring a bit field in C and C++ : The layout of bit fields in a C struct is implementation-defined . For behavior that remains predictable across compilers, it may be preferable to emulate bit fields with
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#17327876688291386-449: Is set i.e., the device has data ready. If the flag-bit had not been set, this would have evaluated to 0 i.e., there is no data available from the device. To check the n th bit from a variable v , perform either of the following: (both are equivalent) Writing, reading or toggling bits in flags can be done only using the OR, AND and NOT operations – operations which can be performed quickly in
1449-487: Is then done by hashing the words of the query and seeing whether all of them match in the QRT. Ultrapeers do that check before forwarding a query to a leaf node, and also before forwarding the query to a peer ultra node provided this is the last hop the query can travel. If a search request turns up a result, the node that has the result contacts the searcher. In the classic Gnutella protocol, response messages were sent back along
1512-538: The Shareaza client, one of the initial G2 clients, could unnecessarily burden the Gnutella network. Both protocols have undergone significant changes since the fork in 2002. G2 has advantages and disadvantages compared to Gnutella. An advantage often cited is that Gnutella2's hybrid search is more efficient than the original Gnutella's query flooding . However, Gnutella replaced query flooding with more efficient search methods, starting with Query Routing in 2002. This
1575-487: The GDF, version 0.6 is what new developers should pursue using the work-in-progress specifications . The Gnutella protocol remains under development. Despite attempts to make a clean break with the complexity inherited from the old Gnutella 0.4 and to design a clean new message architecture, it remains one of the most successful file-sharing protocols to date. The following tables compare general and technical information for
1638-424: The Gnutella network, making it significantly more scalable. If the user decides to download the file, they negotiate the file transfer . If the node which has the requested file is not firewalled , the querying node can connect to it directly. However, if the node is firewalled, stopping the source node from receiving incoming connections, the client wanting to download a file sends it a so-called push request to
1701-432: The Gnutella protocol is currently led by the Gnutella Developers Forum (The GDF). Many protocol extensions have been and are being developed by the software vendors and by the free Gnutella developers of the GDF. These extensions include intelligent query routing, SHA-1 checksums, query hit transmission via UDP , querying via UDP, dynamic queries via TCP , file transfers via UDP, XML metadata, source exchange (also termed
1764-486: The Ultrapeers generally maintain as many leaves as peer connections, while Gnutella2 Hubs maintain far more leaves, and fewer peer (Hub-to-Hub) connections. The reason for this is that the search methods of the various networks have different optimum topologies. Free software Gnutella2 clients include: Proprietary software implementations include: The following table compares general and technical information for
1827-414: The acknowledge packet is not sent, the reliable packet will be retransmitted in an attempt to ensure delivery. Low importance packets, which do not have the flag enabled, do not require an acknowledge packet, reducing reliability, but also reducing overhead, as no acknowledge packet needs to be sent and waited upon. Gnutella2 has an extensible binary packet format, comparable to an XML document tree, which
1890-446: The addresses which it has not yet tried and discarding the addresses which it tried and found to be invalid. When the user wants to do a search, the client sends the request to each actively connected node. In version 0.4 of the protocol, the number of actively connected nodes for a client was quite small (around 5). In that version of the protocol, each node forwards the request to all its actively connected nodes, who, in turn, forward
1953-518: The bit field. Within CPUs and other logic devices, collections of bit fields called flags are commonly used to control or to indicate the outcome of particular operations. Processors have a status register that is composed of flags. For example, if the result of an addition cannot be represented in the destination an arithmetic overflow is set. The flags can be used to decide subsequent operations, such as conditional jump instructions . For example,
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2016-510: The central server, Gnutella cannot be shut down by shutting down any one node. A decentralized network prevents bad actors from taking control of the contents of the network and/or manipulating data by controlling the central server. Gnutella once operated on a purely query flooding -based protocol. The outdated Gnutella version 0.4 network protocol employs five different packet types, namely: These packets facilitate searches. File transfers are instead handled by HTTP . The development of
2079-497: The current state of a flag. For an instance, after an ADC (Add with Carry) instruction, the BVS (Branch on oVerflow Set) instruction may be used to jump based on whether the overflow flag was set by the processor following the result of the addition instruction. A subset of flags in a flag field may be extracted by ANDing with a mask . A large number of languages support the shift operator (<<) where 1 << n aligns
2142-624: The development of distributed hash tables , which are much more scalable but support only exact-match, rather than keyword, search. To address the problems of bottlenecks , Gnutella developers implemented a tiered system of ultrapeers and leaves . Instead of all nodes being considered equal, nodes entering the network were kept at the 'edge' of the network, as a leaf. Leaves don't provide routing. Nodes which are capable of routing messages are promoted to ultrapeers. Ultrapeers accept leaf connections and route searches and network maintenance messages. This allows searches to propagate further through
2205-445: The download mesh ) and parallel downloading in slices (swarming). There are efforts to finalize these protocol extensions in the Gnutella 0.6 specification, at the Gnutella protocol development website. The Gnutella 0.4 standard is outdated but it remains the latest protocol specification because all extensions, so far, exist as proposals. In fact, it is hard or impossible to connect today with 0.4 handshakes. According to developers in
2268-411: The entries which match the search are not found in the routing tables . Gnutella2 relies extensively on UDP , rather than TCP , for searches. The overhead of setting up a TCP connection would make a random walk search system, requiring the contacting of large numbers of nodes with small volumes of data, unworkable. However, UDP is not without its own drawbacks. Because UDP is connectionless, there
2331-419: The file, allowing users to mark viruses and worms on the network, without requiring them to keep a copy. Gnutella2 also utilizes compression in its network connections to reduce the bandwidth used by the network. Shareaza has the additional feature to request previews of images and videos though only FilesScope takes limited advantage of this. gtk-gnutella extended the protocol to further reduce
2394-449: The first open-source (GNU-GPL) programs to implement the Gnutella protocol. The Gnutella network is a fully distributed alternative to such semi-centralized systems as FastTrack ( KaZaA ) and the original Napster . The initial popularity of the network was spurred on by Napster's threatened legal demise in early 2001. This growing surge in popularity revealed the limits of the initial protocol's scalability. In early 2001, variations on
2457-404: The gap between Gnutella and G2. In particular, the semi-reliable UDP layer was enhanced to add cumulative and extended acknowledgments in a way that is backward compatible with legacy G2 clients. Further extensions include the "A" string in /Q2/I and the introduction of /QH2/H/ALT, /QH2/H/PART/MT, /QH2/HN, /QH2/BH and /QH2/G1 in the query hits. Overall, the two networks are fairly similar, with
2520-483: The gnutella network for bootstrapping the new, unrelated network, while proponents of the network claimed that its intent was to remain backwards-compatible with gnutella and to allow current gnutella clients to add Gnutella2 at their leisure. With the developers entrenched in their positions, a flame war soon erupted, further cementing both sides' resolve. The draft specifications were released on March 26, 2003, and more detailed specifications soon followed. G2
2583-413: The gnutella's query flooding system. It is more efficient, as continuing a search does not increase the network traffic exponentially , queries are not routed through as many nodes, and it increases the granularity of a search, allowing a client to stop, once a pre-defined threshold of results has been obtained, more effectively than in gnutella. However, the walk system also increases the complexity of
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2646-571: The maximum number of hops a query can travel was lowered to 4. Leaves and ultrapeers use the Query Routing Protocol to exchange a Query Routing Table (QRT), a table of 64 Ki -slots and up to 2 Mi -slots consisting of hashed keywords. A leaf node sends its QRT to each of the ultrapeers to which it is connected, and ultrapeers merge the QRT of all their leaves (downsized to 128 Ki -slots) plus their own QRT (if they share files) and exchange that with their own neighbors. Query routing
2709-456: The network and the network maintenance and management required, as well as requiring safeguards to prevent a malicious attacker from using the network for denial-of-service attacks . There is also a difference in terminology: while the more capable nodes, which are used to condense the network, are referred to as Ultrapeers in gnutella, they are called Hubs in Gnutella2, and they are also used slightly differently in topology. In gnutella,
2772-454: The network and allows for numerous alterations in topology. This greatly improved efficiency and scalability. Additionally, gnutella adopted a number of other techniques to reduce traffic overhead and make searches more efficient. Most notable are Query Routing Protocol (QRP) and Dynamic Querying (DQ). With QRP, a search reaches only those clients which are likely to have the files, so searches for rare files become far more efficient. With DQ,
2835-424: The network is never completely stable. Also, the bandwidth cost of searching on Gnutella grew exponentially to the number of connected users, often saturating connections and rendering slower nodes useless. Therefore, search requests would often be dropped, and most queries reached only a very small part of the network. This observation identified the Gnutella network as an unscalable distributed system, and inspired
2898-450: The network. In November 2002, Michael Stokes announced the Gnutella2 protocol to the Gnutella Developers Forum. While some thought the goals stated for Gnutella2 are primarily to make a clean break with the gnutella 0.6 protocol and start over, so that some of gnutella's less clean parts would be done more elegantly and, in general, be impressive and desirable; other developers , primarily those of LimeWire and BearShare , thought it to be
2961-444: The primary differences being in the packet format and the search methodology. Gnutella's packet format has been criticized because it was not originally designed with extensibility in mind, and has had many additions over the years, leaving the packet structure cluttered and inefficient. Gnutella2 learned from this, and aside from having many of the added features of gnutella standard in Gnutella2, designed in future extensibility from
3024-431: The programmer can declare a structure for a bit field which labels and determines the width of several subfields. Adjacently declared bit fields of the same type can then be packed by the compiler into a reduced number of words, compared with the memory used if each 'field' were to be declared separately. For languages lacking native bit fields, or where the programmer wants control over the resulting bit representation, it
3087-441: The protocol (first implemented in proprietary and closed source clients) allowed an improvement in scalability. Instead of treating every user as client and server, some users were now treated as ultrapeers , routing search requests and responses for users connected to them. This allowed the network to grow in popularity. In late 2001, the Gnutella client LimeWire Basic became free and open source. In February 2002, Morpheus ,
3150-426: The proxy sends a push request to a leaf on behalf of the client. Normally, it is also possible to send a push request over UDP to the push proxy, which is more efficient than using TCP. Push proxies have two advantages: First, ultrapeer-leaf connections are more stable than routes. This makes push requests much more reliable. Second, it reduces the amount of traffic routed through the Gnutella network. Finally, when
3213-421: The reliable uploading of parts while the file is still being downloaded (swarming), Tiger tree hashes are used. To create a more robust and complete system for searching, Gnutella2 also has a metadata system for more complete labeling, rating, and quality information to be given in the search results than would simply be gathered by the file names. Nodes can even share this information after they have deleted
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#17327876688293276-415: The request. This continues until the packet has reached a predetermined number of hops from the sender (maximum 7). Since version 0.6 (2002 ), Gnutella is a composite network made of leaf nodes and ultra nodes (also called ultrapeers). The leaf nodes are connected to a small number of ultrapeers (typically 3) while each ultrapeer is connected to more than 32 other ultrapeers. With this higher outdegree ,
3339-448: The route taken by the query, as the query itself did not contain identifying information for the node. This scheme was later revised, to deliver search results over UDP , directly to the node that initiated the search, usually an ultrapeer of the node. Thus, in the current protocol, the queries carry the IP address and port number of either node. This lowers the amount of traffic routed through
3402-422: The search stops as soon as the program has acquired enough search results. This vastly reduces the amount of traffic caused by popular searches. One of the benefits of having Gnutella so decentralized is to make it very difficult to shut the network down and to make it a network in which the users are the only ones who can decide which content will be available. Unlike Napster , where the entire network relied on
3465-521: The server for the remote client to initiate the connection instead (to push the file). At first, these push requests were routed along the original chain it used to send the query. This was rather unreliable because routes would often break and routed packets are always subject to flow control. push proxies were introduced to address this problem. These are usually the ultrapeers of a leaf node and they are announced in search results. The client connects to one of these push proxies using an HTTP request and
3528-447: The start. While gnutella uses a query flooding method of searching, Gnutella2 uses a random walk system, where a searching node gathers a list of Hubs and contacts them directly, one at a time. However, as Hub organize themselves in, so called, "Hub clusters ", where each Hub mirrors the information stored by its neighbors, the Leaf is returned the information of the entire Hub cluster (usually 7 Hubs). This has several advantages over
3591-414: The structure can be set or inspected. A bit field is most commonly used to represent integral types of known, fixed bit-width, such as single-bit Booleans . The meaning of the individual bits within the field is determined by the programmer; for example, the first bit in a bit field (located at the field's base address ) is sometimes used to determine the state of a particular attribute associated with
3654-416: Was free software , nothing had prevented the creation of forks that omitted the disabling code, as long as LimeWire trademarks were not used. The shutdown did not affect, for example, FrostWire , a fork of LimeWire created in 2004 that carries neither the remote-disabling code nor adware . On November 9, 2010, LimeWire was resurrected by a secret team of developers and named LimeWire Pirate Edition . It
3717-454: Was based on LimeWire 5.6 BETA. This version had its server dependencies removed and all the PRO features enabled for free. To envision how Gnutella originally worked, imagine a large circle of users (called nodes), each of whom has Gnutella client software. On initial startup, the client software must bootstrap and find at least one other node. Various methods have been used for this, including
3780-459: Was conceived as an answer for some of gnutella's less elegant parts. The packet format was designed so that future network improvements and individual vendor features could be added without worry of causing bugs in other clients on the network. For the purpose file identification and secure integrity check of files it employs SHA-1 hashes . To allow for a file to be reliably downloaded in parallel from multiple sources, as well as to allow for
3843-523: Was prematurely announced on Slashdot , and thousands downloaded the program that day. The source code was to be released later, under the GNU General Public License (GPL); however, the original developers never got the chance to accomplish this purpose. The next day, AOL stopped the availability of the program over legal concerns and restrained Nullsoft from doing any further work on the project. This did not stop Gnutella; after
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#17327876688293906-541: Was proposed in 2001 by Limewire developers. An advantage of Gnutella is its large user base, which numbers in the millions. The G2 network is approximately an order of magnitude smaller. It is difficult to compare the protocols in their current form. The choice of client, on either network, probably affects the end user just as much. Flag field A bit field is a data structure that maps to one or more adjacent bits which have been allocated for specific purposes, so that any single bit or group of bits within
3969-515: Was the most popular file-sharing network on the Internet with an estimated market share of more than 40%. The first client (also called Gnutella) from which the network got its name was developed by Justin Frankel and Tom Pepper of Nullsoft in early 2000, soon after the company's acquisition by AOL . On March 14, the program was made available for download on Nullsoft's servers. The event
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