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82-620: The DE-CIX internet exchange point (IXP) situated in Frankfurt, Germany , is one of the largest IXPs worldwide in terms of peak traffic, with throughput of 17.09 Tbit/s in April 2024. In addition to DE-CIX in Frankfurt, DE-CIX operates IXPs in approx. 40 locations around the globe, with 3 further IXs exchanging peak traffic in excess of 1 Tbit/s, these being DE-CIX New York, DE-CIX Madrid, and DE-CIX Mumbai, [JP2] with DE-CIX Mumbai becoming

164-459: A datagram is called a packet or frame . Packet is used to describe the overall transmission unit and includes the preamble , start frame delimiter (SFD) and carrier extension (if present). The frame begins after the start frame delimiter with a frame header featuring source and destination MAC addresses and the EtherType field giving either the protocol type for the payload protocol or

246-515: A buffer on the switch in its entirety, its frame check sequence verified and only then the packet is forwarded. In modern network equipment, this process is typically done using application-specific integrated circuits allowing packets to be forwarded at wire speed . When a twisted pair or fiber link segment is used and neither end is connected to a repeater, full-duplex Ethernet becomes possible over that segment. In full-duplex mode, both devices can transmit and receive to and from each other at

328-515: A coaxial cable 0.375 inches (9.5 mm) in diameter, later called thick Ethernet or thicknet . Its successor, 10BASE2 , called thin Ethernet or thinnet , used the RG-58 coaxial cable. The emphasis was on making installation of the cable easier and less costly. Since all communication happens on the same wire, any information sent by one computer is received by all, even if that information

410-471: A data throughput of 13.65 terabits per second was achieved at DE-CIX Frankfurt for the first time. According to its Annual Report 2021, DE-CIX had a connected customer capacity of over 96.2 Tbit/s at the end of 2021. The IX operator experienced massive growth during the Covid-19 pandemic, regularly breaking traffic throughput records. DE-CIX Frankfurt, for example, exceeded 9 tbit/s peak traffic for

492-477: A direct link to another ISP and accept a route (normally ignored) to the other ISP through the IXP; if the direct link fails, traffic will then start flowing over the IXP. In this way, the IXP acts as a backup link. When these conditions are met, and a contractual structure exists to create a market to purchase network services, the IXP is sometimes called a "transit exchange". The Vancouver Transit Exchange, for example,

574-581: A doubling of network size. Once repeaters with more than two ports became available, it was possible to wire the network in a star topology . Early experiments with star topologies (called Fibernet ) using optical fiber were published by 1978. Shared cable Ethernet is always hard to install in offices because its bus topology is in conflict with the star topology cable plans designed into buildings for telephony. Modifying Ethernet to conform to twisted-pair telephone wiring already installed in commercial buildings provided another opportunity to lower costs, expand

656-423: A mesh-network topology and provides transport speeds of up to 8 Terabits per second per fiber. DE-CIX Apollon utilizes DWDM equipment and is built on a switching layer supported by Nokia (former Alcatel-Lucent) service routers, which support up to 1440x100 Gigabit Ethernet ports or up to 288x400 Gigabit Ethernet ports. In 2017, DE-CIX began to develop interconnection services for the enterprise sector, beginning with

738-556: A standard for CSMA/CD based on the IEEE 802 draft. Because the DIX proposal was most technically complete and because of the speedy action taken by ECMA which decisively contributed to the conciliation of opinions within IEEE, the IEEE 802.3 CSMA/CD standard was approved in December 1982. IEEE published the 802.3 standard as a draft in 1983 and as a standard in 1985. Approval of Ethernet on

820-425: A standard. As part of that process Xerox agreed to relinquish their 'Ethernet' trademark. The first standard was published on September 30, 1980, as "The Ethernet, A Local Area Network. Data Link Layer and Physical Layer Specifications". This so-called DIX standard (Digital Intel Xerox) specified 10 Mbit/s Ethernet, with 48-bit destination and source addresses and a global 16-bit Ethertype -type field. Version 2

902-401: A switching loop. Autonegotiation is the procedure by which two connected devices choose common transmission parameters, e.g. speed and duplex mode. Autonegotiation was initially an optional feature, first introduced with 100BASE-TX (1995 IEEE 802.3u Fast Ethernet standard), and is backward compatible with 10BASE-T. The specification was improved in the 1998 release of IEEE 802.3. Autonegotiation

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984-402: A thick coaxial cable as a shared medium . This was largely superseded by 10BASE2 , which used a thinner and more flexible cable that was both cheaper and easier to use. More modern Ethernet variants use twisted pair and fiber optic links in conjunction with switches . Over the course of its history, Ethernet data transfer rates have been increased from the original 2.94  Mbit/s to

1066-625: A third site in close proximity to its original roots at the TelecityGroup data center in 2004. Until 2006, Cisco switches supported the growth in customers and traffic. DE-CIX extended its reach to additional data centers, introducing Force10 and Brocade switches and scaling the platform to over 700 10-Gigabit ports. Over the years, DE-CIX has attracted networks from all over the world, especially from Eastern Europe , leading to an annual traffic growth rate of up to 100 percent per year. In 2012, DE-CIX began its international expansion with

1148-455: A transitional strategy, they were effective, providing a bridge from the Internet's beginnings as a government-funded academic experiment, to the modern Internet of many private-sector competitors collaborating to form a network-of-networks, transporting Internet bandwidth from its points-of-production at Internet exchange points to its sites-of-consumption at users' locations. This transition

1230-572: Is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3 . Ethernet has since been refined to support higher bit rates , a greater number of nodes, and longer link distances, but retains much backward compatibility . Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring , FDDI and ARCNET . The original 10BASE5 Ethernet uses

1312-543: Is commonly carried over Ethernet and so it is considered one of the key technologies that make up the Internet . Ethernet was developed at Xerox PARC between 1973 and 1974 as a means to allow Alto computers to communicate with each other. It was inspired by ALOHAnet , which Robert Metcalfe had studied as part of his PhD dissertation and was originally called the Alto Aloha Network. Metcalfe's idea

1394-591: Is described as a "shopping mall" of service providers at one central location, making it easy to switch providers, "as simple as getting a VLAN to a new provider". The VTE is run by BCNET, a public entity. Advocates of green broadband schemes and more competitive telecommunications services often advocate aggressive expansion of transit exchanges into every municipal area network so that competing service providers can place such equipment as video on demand hosts and PSTN switches to serve existing phone equipment, without being answerable to any monopoly incumbent. Since

1476-407: Is either dropped or forwarded to another segment. This reduces the forwarding latency. One drawback of this method is that it does not readily allow a mixture of different link speeds. Another is that packets that have been corrupted are still propagated through the network. The eventual remedy for this was a return to the original store and forward approach of bridging, where the packet is read into

1558-433: Is in turn connected to the cable (with thin Ethernet the transceiver is usually integrated into the network adapter). While a simple passive wire is highly reliable for small networks, it is not reliable for large extended networks, where damage to the wire in a single place, or a single bad connector, can make the whole Ethernet segment unusable. Through the first half of the 1980s, Ethernet's 10BASE5 implementation used

1640-479: Is intended for just one destination. The network interface card interrupts the CPU only when applicable packets are received: the card ignores information not addressed to it. Use of a single cable also means that the data bandwidth is shared, such that, for example, available data bandwidth to each device is halved when two stations are simultaneously active. A collision happens when two stations attempt to transmit at

1722-409: Is mandatory for 1000BASE-T and faster. A switching loop or bridge loop occurs in computer networks when there is more than one Layer 2 ( OSI model ) path between two endpoints (e.g. multiple connections between two network switches or two ports on the same switch connected to each other). The loop creates broadcast storms as broadcasts and multicasts are forwarded by switches out every port ,

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1804-621: Is now used to interconnect appliances and other personal devices . As Industrial Ethernet it is used in industrial applications and is quickly replacing legacy data transmission systems in the world's telecommunications networks. By 2010, the market for Ethernet equipment amounted to over $ 16 billion per year. In February 1980, the Institute of Electrical and Electronics Engineers (IEEE) started project 802 to standardize local area networks (LAN). The DIX group with Gary Robinson (DEC), Phil Arst (Intel), and Bob Printis (Xerox) submitted

1886-436: Is significantly better. In a modern Ethernet, the stations do not all share one channel through a shared cable or a simple repeater hub ; instead, each station communicates with a switch, which in turn forwards that traffic to the destination station. In this topology, collisions are only possible if station and switch attempt to communicate with each other at the same time, and collisions are limited to this link. Furthermore,

1968-412: Is used by the operating system on the receiving station to select the appropriate protocol module (e.g., an Internet Protocol version such as IPv4 ). Ethernet frames are said to be self-identifying , because of the EtherType field. Self-identifying frames make it possible to intermix multiple protocols on the same physical network and allow a single computer to use multiple protocols together. Despite

2050-518: The 10BASE-T standard introduced a full duplex mode of operation which became common with Fast Ethernet and the de facto standard with Gigabit Ethernet . In full duplex, switch and station can send and receive simultaneously, and therefore modern Ethernets are completely collision-free. For signal degradation and timing reasons, coaxial Ethernet segments have a restricted size. Somewhat larger networks can be built by using an Ethernet repeater . Early repeaters had only two ports, allowing, at most,

2132-559: The OSI model , Ethernet provides services up to and including the data link layer . The 48-bit MAC address was adopted by other IEEE 802 networking standards, including IEEE 802.11 ( Wi-Fi ), as well as by FDDI . EtherType values are also used in Subnetwork Access Protocol (SNAP) headers. Ethernet is widely used in homes and industry, and interworks well with wireless Wi-Fi technologies. The Internet Protocol

2214-583: The Spanning Tree Protocol (STP) to maintain a loop-free, meshed network, allowing physical loops for redundancy (STP) or load-balancing (SPB). Shortest Path Bridging includes the use of the link-state routing protocol IS-IS to allow larger networks with shortest path routes between devices. Advanced networking features also ensure port security, provide protection features such as MAC lockdown and broadcast radiation filtering, use VLANs to keep different classes of users separate while using

2296-585: The AMS-IX in Amsterdam and at the DE-CIX in Frankfurt. The principal business and governance models for IXPs include: The technical and business logistics of traffic exchange between ISPs is governed by bilateral or multilateral peering agreements. Under such agreements, traffic is exchanged without compensation. When an IXP incurs operating costs, they are typically shared among all of its participants. At

2378-696: The Internet Industry . Other providers joined and made DE-CIX and Frankfurt the hotspot for the German internet. In 1998, DE-CIX moved its switching hardware to the Interxion data center in Frankfurt. By 2000, DE-CIX had become Germany's largest Internet Exchange and was ranked as one of the larger Internet Exchanges in Europe. DE-CIX added its second switching site at the Interxion campus in 2001 and

2460-487: The LAN was observed. This is in contrast with token passing LANs (Token Ring, Token Bus), all of which suffer throughput degradation as each new node comes into the LAN, due to token waits. This report was controversial, as modeling showed that collision-based networks theoretically became unstable under loads as low as 37% of nominal capacity. Many early researchers failed to understand these results. Performance on real networks

2542-660: The characteristics of the network effect . Internet exchange points began as Network Access Points or NAPs , a key component of Al Gore 's National Information Infrastructure (NII) plan, which defined the transition from the US Government-paid-for NSFNET era (when Internet access was government sponsored and commercial traffic was prohibited) to the commercial Internet of today. The four Network Access Points (NAPs) were defined as transitional data communications facilities at which Network Service Providers (NSPs) would exchange traffic, in replacement of

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2624-455: The destination and the source of each data packet. Ethernet establishes link-level connections, which can be defined using both the destination and source addresses. On reception of a transmission, the receiver uses the destination address to determine whether the transmission is relevant to the station or should be ignored. A network interface normally does not accept packets addressed to other Ethernet stations. An EtherType field in each frame

2706-459: The dissolution of the Internet backbone and transition to the IXP system in 1992, the measurement of Internet traffic exchanged at IXPs has been the primary source of data about Internet bandwidth production: how it grows over time and where it is produced. Standardized measures of bandwidth production have been in place since 1996 and have been refined over time. Ethernet Ethernet ( / ˈ iː θ ər n ɛ t / EE -thər-net )

2788-564: The elimination of the chaining limits inherent in non-switched Ethernet have made switched Ethernet the dominant network technology. Simple switched Ethernet networks, while a great improvement over repeater-based Ethernet, suffer from single points of failure, attacks that trick switches or hosts into sending data to a machine even if it is not intended for it, scalability and security issues with regard to switching loops , broadcast radiation , and multicast traffic. Advanced networking features in switches use Shortest Path Bridging (SPB) or

2870-487: The emerging office communication market, including Siemens' support for the international standardization of Ethernet (April 10, 1981). Ingrid Fromm, Siemens' representative to IEEE 802, quickly achieved broader support for Ethernet beyond IEEE by the establishment of a competing Task Group "Local Networks" within the European standards body ECMA TC24. In March 1982, ECMA TC24 with its corporate members reached an agreement on

2952-1216: The establishment of its first IX outside of Germany, UAE-IX powered by DE-CIX, together with partner du/datamena, in Dubai. Following this, in 2014, DE-CIX established its first IX in North America with the launch of DE-CIX New York. Further expansions followed in close succession, in Southern Europe in 2016, in India in 2018 in India with Mumbai-IX powered by DE-CIX, later to become DE-CIX Mumbai, and in 2021 in Southeast Asia. In September 2022, more than 3,000 network operators (carriers), Internet service providers (ISPs), content providers, corporate networks and other organizations from more than 100 countries were connected to DE-CIX, including major carriers, content and Internet service providers, and numerous enterprise customers. The company operates approx. 40 IXs on 4 continents, and its interconnection services are accessible from data centers in 600+ cities worldwide. In September 2022,

3034-449: The evolution of Ethernet technology, all generations of Ethernet (excluding early experimental versions) use the same frame formats. Mixed-speed networks can be built using Ethernet switches and repeaters supporting the desired Ethernet variants. Due to the ubiquity of Ethernet, and the ever-decreasing cost of the hardware needed to support it, by 2004 most manufacturers built Ethernet interfaces directly into PC motherboards , eliminating

3116-612: The farthest nodes and creates practical limits on how many machines can communicate on an Ethernet network. Segments joined by repeaters have to all operate at the same speed, making phased-in upgrades impossible. To alleviate these problems, bridging was created to communicate at the data link layer while isolating the physical layer. With bridging, only well-formed Ethernet packets are forwarded from one Ethernet segment to another; collisions and packet errors are isolated. At initial startup, Ethernet bridges work somewhat like Ethernet repeaters, passing all traffic between segments. By observing

3198-672: The first time in March 2020, and 10 tbit/s in November of the same year. In 2013, DE-CIX introduced DE-CIX Apollon, its new Ethernet -based platform. Today, the platform utilizes the ADVA Optical Networking FSP 3000 and Infinera CloudExpress 2 gear for the optical backbone, and Nokia’s 7950 XRS series and Nokia’s 7750 SR-s series for the IP network. The optical backbone has a total capacity of 48 Terabits per second across

3280-619: The global business as the Management Board. Felix Höger, Klaus Landefeld, Rudolf van Megen and Harald A. Summa represent the Supervisory Board of DE-CIX Group AG. In addition, Harald A. Summa was the Managing Director of DE-CIX Group AG from 1996 to 2022 and Chair of the Management Board from 2017 to 2022. DE-CIX was founded in 1995 by three Internet Service Providers (ISPs). Back then, German Internet traffic

3362-510: The group was split into three subgroups, and standardization proceeded separately for each proposal. Delays in the standards process put at risk the market introduction of the Xerox Star workstation and 3Com's Ethernet LAN products. With such business implications in mind, David Liddle (General Manager, Xerox Office Systems) and Metcalfe (3Com) strongly supported a proposal of Fritz Röscheisen ( Siemens Private Networks) for an alliance in

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3444-439: The installed base, and leverage building design, and, thus, twisted-pair Ethernet was the next logical development in the mid-1980s. Ethernet on unshielded twisted-pair cables (UTP) began with StarLAN at 1 Mbit/s in the mid-1980s. In 1987 SynOptics introduced the first twisted-pair Ethernet at 10 Mbit/s in a star-wired cabling topology with a central hub, later called LattisNet . These evolved into 10BASE-T, which

3526-510: The international level was achieved by a similar, cross- partisan action with Fromm as the liaison officer working to integrate with International Electrotechnical Commission (IEC) Technical Committee 83 and International Organization for Standardization (ISO) Technical Committee 97 Sub Committee 6. The ISO 8802-3 standard was published in 1989. Ethernet has evolved to include higher bandwidth, improved medium access control methods, and different physical media. The multidrop coaxial cable

3608-597: The introduction of DirectCLOUD, a service that enables customers to access cloud service providers.  In 2022, the DirectCLOUD service enables connectivity to more than 50 cloud service providers, including specialized local CSPs and global hyperscalers. Other interconnection services specifically designed for the needs of enterprises include: the Microsoft Azure Peering Service, Closed User Groups, and InterconnectionFLEX. In 2019, DE-CIX

3690-1318: The largest IXP in the APAC according to PeeringDB in 2021 [JE3]. The DE-CIX global IXs (including presence in partner IXs) include: Europe: Barcelona , Berlin (powered by BCIX), Bucharest (powered by InterLAN), Düsseldorf , Frankfurt, Hamburg , Istanbul , Leipzig , Lisbon , Madrid ,  Marseille , Munich , Palermo , Prague (powered by NIX.CZ) , Ruhr-CIX powered by DE-CIX, SEE-CIX powered by DE-CIX in Athens and Warsaw (powered by ATMAN) Nordics: Copenhagen , Esbjerg , Helsinki , Kristiansand , Oslo Africa: Kinshasa (DRC), Lagos (Nigeria), and Tripoli (Libya) North America: Chicago , Dallas , New York , Phoenix , and Richmond GCC: Aqaba IX powered by DE-CIX in Jordan, UAE-IX powered by DE-CIX in Dubai), IRAQ-IXP powered by DE-CIX India: Chennai , Delhi , Mumbai , and Kolkata Southeast Asia: Singapore , Kuala Lumpur , Johor Bahru , Bandar Seri Begawan (Borneo-IX powered by DE-CIX) and Manila (powered by GetaFIX) Ivo Ivanov (CEO), Thomas King (CTO), Christian Reuter (CSO) and Sebastian Seifert (CFO) are responsible for

3772-547: The largest computer networks in the world at that time. An Ethernet adapter card for the IBM PC was released in 1982, and, by 1985, 3Com had sold 100,000. In the 1980s, IBM's own PC Network product competed with Ethernet for the PC, and through the 1980s, LAN hardware, in general, was not common on PCs. However, in the mid to late 1980s, PC networking did become popular in offices and schools for printer and fileserver sharing, and among

3854-502: The latest 400 Gbit/s , with rates up to 1.6  Tbit/s under development. The Ethernet standards include several wiring and signaling variants of the OSI physical layer . Systems communicating over Ethernet divide a stream of data into shorter pieces called frames . Each frame contains source and destination addresses, and error-checking data so that damaged frames can be detected and discarded; most often, higher-layer protocols trigger retransmission of lost frames. Per

3936-399: The length of the payload. The middle section of the frame consists of payload data including any headers for other protocols (for example, Internet Protocol) carried in the frame. The frame ends with a 32-bit cyclic redundancy check , which is used to detect corruption of data in transit . Notably, Ethernet packets have no time-to-live field , leading to possible problems in the presence of

4018-631: The many diverse competing LAN technologies of that decade, Ethernet was one of the most popular. Parallel port based Ethernet adapters were produced for a time, with drivers for DOS and Windows. By the early 1990s, Ethernet became so prevalent that Ethernet ports began to appear on some PCs and most workstations . This process was greatly sped up with the introduction of 10BASE-T and its relatively small modular connector , at which point Ethernet ports appeared even on low-end motherboards. Since then, Ethernet technology has evolved to meet new bandwidth and market requirements. In addition to computers, Ethernet

4100-515: The market at their peak, and there was an attempt by Stockholm -based IXP NetNod to use SRP/DPT , but Ethernet has prevailed, accounting for more than 95% of all existing Internet exchange switch fabrics. All Ethernet port speeds are to be found at modern IXPs, ranging from 10 Mb /second ports in use in small developing-country IXPs, to ganged 10 Gb /second ports in major centers like Seoul, New York, London, Frankfurt, Amsterdam, and Palo Alto. Ports with 100 Gb/second are available, for example, at

4182-401: The mixing of speeds, both of which are critical to the incremental deployment of faster Ethernet variants. In 1989, Motorola Codex introduced their 6310 EtherSpan, and Kalpana introduced their EtherSwitch; these were examples of the first commercial Ethernet switches. Early switches such as this used cut-through switching where only the header of the incoming packet is examined before it

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4264-484: The more expensive exchanges, participants pay a monthly or annual fee, usually determined by the speed of the port or ports which they are using. Fees based on the volume of traffic are less common because they provide a counterincentive to the growth of the exchange. Some exchanges charge a setup fee to offset the costs of the switch port and any media adaptors ( gigabit interface converters , small form-factor pluggable transceivers , XFP transceivers , XENPAKs , etc.) that

4346-476: The need for a separate network card. Ethernet was originally based on the idea of computers communicating over a shared coaxial cable acting as a broadcast transmission medium. The method used was similar to those used in radio systems, with the common cable providing the communication channel likened to the Luminiferous aether in 19th-century physics, and it was from this reference that the name Ethernet

4428-470: The network. Despite the physical star topology and the presence of separate transmit and receive channels in the twisted pair and fiber media, repeater-based Ethernet networks still use half-duplex and CSMA/CD, with only minimal activity by the repeater, primarily generation of the jam signal in dealing with packet collisions. Every packet is sent to every other port on the repeater, so bandwidth and security problems are not addressed. The total throughput of

4510-779: The networks and creating the Internet: Commercialization, privatization, broader access leads to the modern Internet: Examples of Internet services: Internet exchange points ( IXes or IXPs ) are common grounds of IP networking, allowing participant Internet service providers (ISPs) to exchange data destined for their respective networks. IXPs are generally located at places with preexisting connections to multiple distinct networks, i.e. , datacenters , and operate physical infrastructure ( switches ) to connect their participants. Organizationally, most IXPs are each independent not-for-profit associations of their constituent participating networks (that is,

4592-623: The new participant requires. Internet traffic exchange between two participants on an IXP is facilitated by Border Gateway Protocol (BGP) routing configurations between them. They choose to announce routes via the peering relationship – either routes to their own addresses or routes to addresses of other ISPs that they connect to, possibly via other mechanisms. The other party to the peering can then apply route filtering , where it chooses to accept those routes, and route traffic accordingly, or to ignore those routes, and use other routes to reach those addresses. In many cases, an ISP will have both

4674-577: The now-ubiquitous twisted pair with 10BASE-T. By the end of the 1980s, Ethernet was clearly the dominant network technology. In the process, 3Com became a major company. 3Com shipped its first 10 Mbit/s Ethernet 3C100 NIC in March 1981, and that year started selling adapters for PDP-11s and VAXes , as well as Multibus -based Intel and Sun Microsystems computers. This was followed quickly by DEC's Unibus to Ethernet adapter, which DEC sold and used internally to build its own corporate network, which reached over 10,000 nodes by 1986, making it one of

4756-408: The participating ISPs connect. Prior to the existence of switches, IXPs typically employed fiber-optic inter-repeater link (FOIRL) hubs or Fiber Distributed Data Interface (FDDI) rings, migrating to Ethernet and FDDI switches as those became available in 1993 and 1994. Asynchronous Transfer Mode (ATM) switches were briefly used at a few IXPs in the late 1990s, accounting for approximately 4% of

4838-555: The phrase lives on to a small degree, among those who conflate the NAPs with IXPs. The primary purpose of an IXP is to allow networks to interconnect directly, via the exchange, rather than going through one or more third-party networks. The primary advantages of direct interconnection are cost, latency , and bandwidth . Traffic passing through an exchange is typically not billed by any party, whereas traffic to an ISP's upstream provider is. The direct interconnection, often located in

4920-450: The port they are intended for, traffic on a switched Ethernet is less public than on shared-medium Ethernet. Despite this, switched Ethernet should still be regarded as an insecure network technology, because it is easy to subvert switched Ethernet systems by means such as ARP spoofing and MAC flooding . The bandwidth advantages, the improved isolation of devices from each other, the ability to easily mix different speeds of devices and

5002-526: The publicly financed NSFNET Internet backbone. The National Science Foundation let contracts supporting the four NAPs, one to MFS Datanet for the preexisting MAE-East in Washington, D.C., and three others to Sprint , Ameritech , and Pacific Bell , for new facilities of various designs and technologies, in New York (actually Pennsauken, New Jersey ), Chicago, and California, respectively. As

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5084-411: The repeater is limited to that of a single link, and all links must operate at the same speed. While repeaters can isolate some aspects of Ethernet segments , such as cable breakages, they still forward all traffic to all Ethernet devices. The entire network is one collision domain , and all hosts have to be able to detect collisions anywhere on the network. This limits the number of repeaters between

5166-490: The rest of the Internet. However, a connection to a local IXP may allow them to transfer data without limit, and without cost, vastly improving the bandwidth between customers of such adjacent ISPs. Internet Exchange Points (IXPs) are public locations where several networks are connected to each other. Public peering is done at IXPs, while private peering can be done with direct links between networks. A typical IXP consists of one or more network switches , to which each of

5248-513: The same city as both networks, avoids the need for data to travel to other cities—and potentially on other continents—to get from one network to another, thus reducing latency. The third advantage, speed, is most noticeable in areas that have poorly developed long-distance connections. ISPs in regions with poor connections might have to pay between 10 or 100 times more for data transport than ISPs in North America, Europe, or Japan. Therefore, these ISPs typically have slower, more limited connections to

5330-549: The same physical infrastructure, employ multilayer switching to route between different classes, and use link aggregation to add bandwidth to overloaded links and to provide some redundancy. In 2016, Ethernet replaced InfiniBand as the most popular system interconnect of TOP500 supercomputers. The Ethernet physical layer evolved over a considerable time span and encompasses coaxial, twisted pair and fiber-optic physical media interfaces, with speeds from 1 Mbit/s to 400 Gbit/s . The first introduction of twisted-pair CSMA/CD

5412-482: The same time, and there is no collision domain. This doubles the aggregate bandwidth of the link and is sometimes advertised as double the link speed (for example, 200 Mbit/s for Fast Ethernet). The elimination of the collision domain for these connections also means that all the link's bandwidth can be used by the two devices on that segment and that segment length is not limited by the constraints of collision detection. Since packets are typically delivered only to

5494-512: The same time. They corrupt transmitted data and require stations to re-transmit. The lost data and re-transmission reduces throughput. In the worst case, where multiple active hosts connected with maximum allowed cable length attempt to transmit many short frames, excessive collisions can reduce throughput dramatically. However, a Xerox report in 1980 studied performance of an existing Ethernet installation under both normal and artificially generated heavy load. The report claimed that 98% throughput on

5576-508: The set of ISPs that participate in that IXP). The primary alternative to IXPs is private peering , where ISPs directly connect their networks. IXPs reduce the portion of an ISP's traffic that must be delivered via their upstream transit providers, thereby reducing the average per-bit delivery cost of their service. Furthermore, the increased number of paths available through the IXP improves routing efficiency (by allowing routers to select shorter paths) and fault-tolerance . IXPs exhibit

5658-413: The so-called Blue Book CSMA/CD specification as a candidate for the LAN specification. In addition to CSMA/CD, Token Ring (supported by IBM) and Token Bus (selected and henceforward supported by General Motors ) were also considered as candidates for a LAN standard. Competing proposals and broad interest in the initiative led to strong disagreement over which technology to standardize. In December 1980,

5740-411: The source addresses of incoming frames, the bridge then builds an address table associating addresses to segments. Once an address is learned, the bridge forwards network traffic destined for that address only to the associated segment, improving overall performance. Broadcast traffic is still forwarded to all network segments. Bridges also overcome the limits on total segments between two hosts and allow

5822-482: The switch or switches will repeatedly rebroadcast the broadcast messages flooding the network. Since the Layer 2 header does not support a time to live (TTL) value, if a frame is sent into a looped topology, it can loop forever. A physical topology that contains switching or bridge loops is attractive for redundancy reasons, yet a switched network must not have loops. The solution is to allow physical loops, but create

5904-533: The system was deployed at PARC, Metcalfe and Boggs published a seminal paper. Ron Crane , Yogen Dalal , Robert Garner, Hal Murray, Roy Ogus, Dave Redell and John Shoch facilitated the upgrade from the original 2.94 Mbit/s protocol to the 10 Mbit/s protocol, which was released to the market in 1980. Metcalfe left Xerox in June 1979 to form 3Com . He convinced Digital Equipment Corporation (DEC), Intel , and Xerox to work together to promote Ethernet as

5986-557: The three telco-operated NAPs faded into obscurity relatively quickly after the expiration of the federal subsidies, MAE-East , thrived for fifteen more years, and its west-coast counterpart MAE-West continued for more than twenty years. Today, the phrase "Network Access Point" is of historical interest only, since the four transitional NAPs disappeared long ago, replaced by hundreds of modern Internet exchange points, though in Spanish-speaking Latin America ,

6068-766: Was StarLAN , standardized as 802.3 1BASE5. While 1BASE5 had little market penetration, it defined the physical apparatus (wire, plug/jack, pin-out, and wiring plan) that would be carried over to 10BASE-T through 10GBASE-T. The most common forms used are 10BASE-T, 100BASE-TX, and 1000BASE-T . All three use twisted-pair cables and 8P8C modular connectors . They run at 10 Mbit/s , 100 Mbit/s , and 1 Gbit/s , respectively. Fiber optic variants of Ethernet (that commonly use SFP modules ) are also very popular in larger networks, offering high performance, better electrical isolation and longer distance (tens of kilometers with some versions). In general, network protocol stack software will work similarly on all varieties. In IEEE 802.3,

6150-435: Was derived. Original Ethernet's shared coaxial cable (the shared medium) traversed a building or campus to every attached machine. A scheme known as carrier-sense multiple access with collision detection (CSMA/CD) governed the way the computers shared the channel. This scheme was simpler than competing Token Ring or Token Bus technologies. Computers are connected to an Attachment Unit Interface (AUI) transceiver , which

6232-446: Was designed for point-to-point links only, and all termination was built into the device. This changed repeaters from a specialist device used at the center of large networks to a device that every twisted pair-based network with more than two machines had to use. The tree structure that resulted from this made Ethernet networks easier to maintain by preventing most faults with one peer or its associated cable from affecting other devices on

6314-555: Was essentially to limit the Aloha-like signals inside a cable, instead of broadcasting into the air. The idea was first documented in a memo that Metcalfe wrote on May 22, 1973, where he named it after the luminiferous aether once postulated to exist as an "omnipresent, completely passive medium for the propagation of electromagnetic waves." In 1975, Xerox filed a patent application listing Metcalfe, David Boggs , Chuck Thacker , and Butler Lampson as inventors. In 1976, after

6396-465: Was one of 3 IX operators to jointly develop the IX-API, which provides the basis for the automation of interconnection services over IXPs. In 2021, DE-CIX received a patent for its security service “Blackholing Advanced”, which enables innovative filtering mechanisms in the protection of networks against DDoS attacks. Internet exchange point Early research and development: Merging

6478-642: Was particularly timely, coming hard on the heels of the ANS CO+RE controversy , which had disturbed the nascent industry, led to congressional hearings, resulted in a law allowing NSF to promote and use networks that carry commercial traffic, prompted a review of the administration of NSFNET by the NSF's Inspector General (no serious problems were found), and caused commercial operators to realize that they needed to be able to communicate with each other independent of third parties or at neutral exchange points. Although

6560-412: Was published in November 1982 and defines what has become known as Ethernet II . Formal standardization efforts proceeded at the same time and resulted in the publication of IEEE 802.3 on June 23, 1983. Ethernet initially competed with Token Ring and other proprietary protocols . Ethernet was able to adapt to market needs, and with 10BASE2 shift to inexpensive thin coaxial cable, and from 1990 to

6642-407: Was replaced with physical point-to-point links connected by Ethernet repeaters or switches . Ethernet stations communicate by sending each other data packets : blocks of data individually sent and delivered. As with other IEEE 802 LANs, adapters come programmed with globally unique 48-bit MAC address so that each Ethernet station has a unique address. The MAC addresses are used to specify both

6724-593: Was still exchanged in the United States. To improve latency and reduce costs for backhaul connectivity, three providers decided to establish an Internet Exchange in the back room of a postal office in Gutleutviertel in Frankfurt. Hamburg-based MAZ, EUnet from Dortmund and XLink from Karlsruhe were the first to connect their networks in Frankfurt at DE-CIX. DE-CIX was originally managed by Electronic Commerce Forum, now known as eco – Association of

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