If I were hired by the University President as an IT consultant, I would rather suggest Infrastructure in order for internet connectivity be improved. First in foremost, I will define and discuss first all about the Internet and its OSI Model.The Internet
The Internet is a worldwide network of computers and computer networks that can communicate with each other using the Internet Protocol. Any computer on the Internet has a unique IP address that can be used by other computers to route information to it. Hence, any computer on the Internet can send a message to any other computer using its IP address. These messages carry with them the originating computer's IP address allowing for two-way communication. In this way, the Internet can be seen as an exchange of messages between computers.
The Internet works in part because of protocols that govern how the computers and routers communicate with each other. The nature of computer network communication lends itself to a layered approach where individual protocols in the protocol stack run more-or-less independently of other protocols. This allows lower-level protocols to be customized for the network situation while not changing the way higher-level protocols operate. A practical example of why this is important is because it allows an Internet browser to run the same code regardless of whether the computer it is running on is connected to the Internet through an Ethernet or Wi-Fi connection. Protocols are often talked about in terms of their place in the OSI reference model, which emerged in 1983 as the first step in an unsuccessful attempt to build a universally adopted networking protocol suite.
The OSI Reference ModelFor the Internet, the physical medium and data link protocol can vary several times as packets traverse the globe. This is because the Internet places no constraints on what physical medium or data link protocol is used. This leads to the adoption of media and protocols that best suit the local network situation. In practice, most intercontinental communication will use the Asynchronous Transfer Mode (ATM) protocol (or a modern equivalent) on top of optic fibre. This is because for most intercontinental communication the Internet shares the same infrastructure as the public switched telephone network.
At the network layer, things become standardized with the Internet Protocol (IP) being adopted for logical addressing. For the World Wide Web, these “IP addresses” are derived from the human readable form using the Domain Name System (e.g. 72.14.207.99 is derived from www.google.com). At the moment, the most widely used version of the Internet Protocol is version four but a move to version six is imminent.
At the transport layer, most communication adopts either the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). TCP is used when it is essential every message sent is received by the other computer where as UDP is used when it is merely desirable. With TCP, packets are retransmitted if they are lost and placed in order before they are presented to higher layers. With UDP, packets are not ordered or retransmitted if lost. Both TCP and UDP packets carry port numbers with them to specify what application or process the packet should be handled by. Because certain application-level protocols use certain ports, network administrators can manipulate traffic to suit particular requirements. Examples are to restrict Internet access by blocking the traffic destined for a particular port or to affect the performance of certain applications by assigning priority.
Above the transport layer, there are certain protocols that are sometimes used and loosely fit in the session and presentation layers, most notably the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols. These protocols ensure that the data transferred between two parties remains completely confidential and one or the other is in use when a padlock appears in the address bar of your web browser. Finally, at the application layer, are many of the protocols Internet users would be familiar with such as HTTP (web browsing), POP3 (e-mail), FTP (file transfer), IRC (Internet chat), BitTorrent (file sharing) and OSCAR (instant messaging).
Local Area Networks
Despite the growth of the Internet, the characteristics of local area networks (computer networks that run at most a few kilometres) remain distinct. This is because networks on this scale do not require all the features associated with larger networks and are often more cost-effective and efficient without them.
In the mid-1980s, several protocol suites emerged to fill the gap between the data link and applications layer of the OSI reference model. These were Appletalk, IPX and NetBIOS with the dominant protocol suite during the early 1990s being IPX due to its popularity with MS-DOS users. TCP/IP existed at this point but was typically only used by large government and research facilities. As the Internet grew in popularity and a larger percentage of traffic became Internet-related, local area networks gradually moved towards TCP/IP and today networks mostly dedicated to TCP/IP traffic are common. The move to TCP/IP was helped by technologies such as DHCP that allowed TCP/IP clients to discover their own network address — a functionality that came standard with the AppleTalk/IPX/NetBIOS protocol suites.
It is at the data link layer though that most modern local area networks diverge from the Internet. Whereas Asynchronous Transfer Mode (ATM) or Multiprotocol Label Switching (MPLS) are typical data link protocols for larger networks, Ethernet and Token Ring are typical data link protocols for local area networks. These protocols differ from the former protocols in that they are simpler (e.g. they omit features such as Quality of Service guarantees) and offer collision prevention. Both of these differences allow for more economic set-ups.
Despite the modest popularity of Token Ring in the 80's and 90's, virtually all local area networks now use wired or wireless Ethernet. At the physical layer, most wired Ethernet implementations use copper twisted-pair cables (including the common 10BASE-T networks). However, some early implementations used coaxial cables and some recent implementations (especially high-speed ones) use optic fibres. Where optic fibre is used, the distinction must be made between multi-mode fibre and single-mode fibre. Multi-mode fibre can be thought of as thicker optical fibre that is cheaper to manufacture but that suffers from less usable bandwidth and greater attenuation (i.e. poor long-distance performance).
Wide Area Network
Network infrastructure is the underlying system of cabling, phone lines, hubs, switches, routers and other devices that connect various parts of an organization through a Wide Area Network (WAN). If a sound network infrastructure is in place, most users can connect people and information throughout their organization and beyond to accomplish assigned responsibilities. Without a network infrastructure, such capabilities are available piecemeal, usually to individuals who may have the vision, initiative and resources to create this capability for themselves.
A WAN allows users to communicate with other personnel within the organization through tools such as e-mail systems. The WAN also provides a bridge to the Internet and World Wide Web that allows anyone connected to the WAN to access information and people outside the organization. WANs are usually "closed" through security measures that prevent external third parties from accessing information within the WAN without a password and/or personal identification number.
A key function of a WAN is to connect Local Area Networks (LANs) throughout the colleges. The LAN is housed within a building and serves to connect all users within that building to one local network. By connecting the LAN to a WAN, all LAN users gain access to others in the enterprise and to the electronic world beyond the network. A community college that has every user connected through a LAN to a WAN has established the infrastructure necessary to take full advantage of the telecommunications capabilities that exist today and those that will be available in the future. ACCD's network infrastructure consists of a WAN that connects the college's four campuses to the district IS data operations center and to the satellite campuses. Each ACCD campus connects to the Internet through gigabit Ethernet lines using an Alcatel OS9 router and an Alcatel 7800 Gigabit Ethernet switch located at the central district data operations center.
Gigabit Ethernet is a LAN architecture that supports data transfer rates of 1 gigabit (1,000 megabits) per second. The Cisco 7513 Internet router is used to provide video links to Regions 13 and 20 Education Service Centers (ESC). The networking infrastructure also includes e-mail servers and a Cisco Pix firewall to prevent intruders using an Internet connection from accessing ACCDs internal network.
Some Technical Terms related on Internet Connection
Bandwidth describes the data throughput capacity of a particular communications technology or link. It is closely analogous to the carrying capacity of a water pipe. It is usually measured as the number of bits of information per second that can be transferred, a bit being a single binary digit (either '0' or '1'). A single alphanumeric character is usually represented by a string of eight bits (a byte). Allowing for overheads, the rate at which characters can be transferred over a particular link is roughly one tenth of the specified bit transfer rate. So, for example, at a relatively low transfer rate of 14,400 bits per second (14.4 Kbps) a page of text of say 2,500 characters (approximately 20,000 bits) would take nearly 2 seconds.
A full colour picture (image) could require 100 Kbits to represent a 25x25 mm2 area. Usually images are compressed using a system such as JPEG (for Joint Photographic Experts Group) which can reduce this by a factor of 10 to 100, depending on the richness of the visual information. A video clip, with sound and pictures, is similar to a series of pictures and a 60 second segment using a small frame (75x50 mm2) and a low quality compression system can take up 4 Mbits (500 Kbytes), which would take almost five minutes to download using a 14.4 Kbps line running at full capacity. On the other hand, a full screen broadcast quality image with 720x480 resolution using MPEG-2 (for Moving Pictures Experts Group), such as is used for DVD movies, requires up to 15 Mbps of bandwidth. The various rates are compared in Table 1.
Low bandwidth (or low speed) links are anything below 100,000 bits per second (represented as 100 Kbps). High bandwidth or high speed links are in the range 100 Kbps to 2,000 Kbps which is usually presented as 2 Mbps.
Broadband commonly refers to a data throughput capacity of more than 2 Mbps. The term reflects the ability of such links to handle many different types of information up to and including full motion video and other services requiring very large throughput capability.
Analogue vs Digital. Analogue information is based on signals where some feature of the signal, usually amplitude or phase, varies continuously with time. Digital information (a 1 or 0), on the other hand, is represented by just one of two possible states: high/low (voltage), on/off (signal) etc. Computers deal with digital information. It is often necessary to convert the digital information used in the computers into analogue signals in order for it to be transmitted over a communications link and then convert it back to digital form when received. A modem (modulator/demodulator) is used to carry out the analogue to digital conversion, and its reverse.
The upper limit of data carrying capacity over a normal telephone line for analogue communications is 56 Kbps (and this only under favourable conditions) whereas digital communications can range up to several megabits per second (1 Mbps plus). In general, analogue signals are better over long distances and noisy lines.
Cable modems, which connect to co-axial cable networks, can carry data at speeds up to 2 Mbps. Digital signals can be used for higher data speeds but require high line quality and can usually be sent only over relatively short distances.
Fibre optic cables always transmit digital signals and under appropriate conditions can reach into the Gigabit range (1,000 Mbps plus). Fibre is widely used for the high volume inter city telecommunications, backbone and international links but is only slowly being deployed for business and domestic use.
The Internet Connection Infrastructure
In information technology and on the Internet, Infrastructure is the physical hardware used to interconnect computers and users. Infrastructure includes the transmission media, including telephone lines, cable television lines, and satellites and antennas, and also the routers, aggregators, repeaters, and other devices that control transmission paths. Infrastructure also includes the software used to send, receive, and manage the signals that are transmitted.
In some usages, infrastructure refers to interconnecting hardware and software and not to computers and other devices that are interconnected. However, to some information technology users, infrastructure is viewed as everything that supports the flow and processing of information.
Infrastructure companies play a significant part in evolving the Internet, both in terms of where the interconnections are placed and made accessible and in terms of how much information can be carried how quickly.
The figure below shows the relationships between some of the key entities which make up the internet connection infrastructure.
Some elements of the telecommunications/Internet infrastructure
Local loop: This includes the copper wire pairs that link terminals (commonly telephones) to their nearest exchange but may also in some rural areas include multi-access radio technology.
Internet Service Provider (ISP): The ISP is integral to connection to the Internet. It is the ISP who provides the Internet Protocol (IP) linking services which allow messages to be routed throughout the Internet 'cloud'. Most ISPs will have one or more broadband or high bandwidth connections to the telecommunications backbone which both allows users to connect to the ISP and links the ISP to other IP service providers on the Internet.
Telephone Exchange: Internet connection capacity is normally dependent on the capacity of the link between a user and their local telephone exchange, which will in turn depend on the location and the age and quality of the exchange's equipment. Many Telecom NZ exchanges in rural and congested urban areas were upgraded in the early 1980s and continue to provide good standard telephone services but are not able to provide services and access speeds which are available through a modern exchange.
Backbone: The telecommunications backbone is the network which links exchanges to each other and includes both transmission and circuit switching elements. The transmission elements may include copper and optical fibre cabling, and microwave links. The international circuits also include satellite links. Parts of the existing domestic backbone between some provincial centres may require upgrading to support greater digital data flows.
Technologies Available and in Use
Aside from dedicated fibre-optic and coaxial cable networks and wireless connections, which are available at present, access to the Internet is generally only available over the telephone network. Even for those with satellite connections, the return path from the user to the ISP relies on the telephone network. Thus, in practice for the overwhelming majority, technologies available for Internet connection are limited to those capable of using the copper wire local loop.
Technologies available over the local loop
V90 Modem: This is presently the 'domestic standard' for achieving a data rate of up to 56 Kbps over a standard telephone line. It requires only an inexpensive modem connecting a personal computer to a telephone line, and will support slow-motion video. There are limiting factors, however. A connection speed of 56 Kbps cannot be realised if there is more than one analogue-to-digital conversion in the connection to the ISP and is usually limited to a maximum line length between subscribers and the nearest exchange of 3 to 5 kilometres. In practice this means that for many users access speeds are less than the theoretical maximum. Typically in urban areas 33 Kbps is available but in many rural areas line quality is such that speeds fall well below this. For example, many rural areas are served with multi-access radio technology, which was introduced over ten years ago to eliminate party lines, and can only handle data transfer rates of 9.6 Kbps.
ADSL (Asynchronous Digital Subscriber Line): This is one of a family of technologies referred to collectively as xDSL, a term covering different types of Digital Subscriber Lines. xDSL technologies use sophisticated modulation schemes to pack digital data onto copper wires. xDSL is similar to ISDN (see below) inasmuch as both operate over existing copper telephone lines, but requires short runs to a central telephone exchange (about 2 kilometres). Potentially, xDSL offers broadband level speeds - up to 32 Mbps for downstream traffic, and from 32 kbps to over 1 Mbps for upstream traffic.
ADSL is offered by Telecom NZ to subscribers as JetStream. It is capable of speeds of up to (but generally much less than ) 6 Mbps in one direction and a much lesser speed in the other. It is currently available only in the main centres but is slated to be rolled out progressively throughout the country and is displacing ISDN (see below). However, this may be slow (after almost 20 years, ISDN still does not reach into most of rural New Zealand). Given that even inner city suburbs in areas such as Wellington cannot presently be serviced with ADSL, some further technology development will be required before ADSL can provide a widespread solution to bandwidth limitations, especially in rural areas.
ISDN (Integrated Services Digital Network): Telecom provides ISDN in all the main centres as well as many of the smaller centres, however, with one or two exceptions it is not generally available in rural areas. The technology supports data transfer rates of from 64 Kbps to 2 Mbps. Basic Rate ISDN installations provide the equivalent of two standard telephone lines. One can be used for voice and the other for data, or both lines can be used to achieve data rates of 128 Kbps. This is just adequate for two-way video applications such as distance learning and video-conferencing. Multiple ISDN lines can be used to obtain higher quality connections, for example, three ISDN lines provide a connection speed of 384 Kbps and this is typically used where video quality is critical, for example for tele-medicine applications. Telecom NZ has demonstrated a reluctance to make further investment in its ISDN infrastructure, promoting ADSL services as a preferred alternative.
Frame Relay: This is available from 64 Kbps and is easily scalable up to 2 Mbps. Frame relay is generally used as a dedicated point-to-point service or as a virtual private network and has the advantage of fixed price tariffs (no usage charges). The technology is specially suited to applications where guaranteed bandwidth is required such as for voice and video applications.
Asynchronous Transfer Mode (ATM): This technology offers very high bandwidth, up to 150 Mbps and is typically used for linking corporate networks.
IP Networking: This is a new family of services being piloted by Telecom NZ which is specially suitable for Internet connections where dedicated bandwidth is not critical. The focus is on flexibility and interconnectivity between a variety of connection services, such as dial-up telephone, ISDN and frame relay.
Rural issues with the local loop
While in some urban areas high bandwidth and even broadband access speeds are available, telephone subscribers more than 3 to 5 kilometres from an exchange are limited to access rates of 33 Kbps or less. In addition there are major problems with line quality reported for rural subscribers. A recent survey conducted for MAF reported 54% of rural subscribers as having problems affecting telephone lines including noise, electric fences (often a problem of poor fence installation by the farmer) and exchange overload. Telecom NZ reports that only 5% percent of local loop lines are not capable of maintaining a reliable data speed of 14.4 Kbps. The overwhelming majority of these would be in rural areas and thus this figure represents a large proportion of rural subscribers.
An indicator of insufficient infrastructure capacity is the number of reported problems with obtaining a second or third telephone line (an obvious way of trying to bypass the data rate bottleneck). Over one third of survey respondents who indicated that they had attempted to get a second line failed to do so.
Reference:
•http://en.wikipedia.org/wiki/Telecommunications
•http://images.google.com.ph/imgres?imgurl=http://www.window.state.tx.us/tspr/alamoccd/ex8-19.gif&imgrefurl=http://www.window.state.tx.us/tspr/alamoccd/ch08c.htm&usg=__QFFE6JleZKYmdBSFMxH9KzOBsc0=&h=873&w=762&sz=24&hl=tl&start=13&um=1&tbnid=h6u3xK_4vRUjgM:&tbnh=146&tbnw=127&prev=/images%3Fq%3Dinternet%2Bconnectivity%2Binfrastructure%26hl%3Dtl%26um%3D1
•http://searchdatacenter.techtarget.com/sDefinition/0,,sid80_gci212346,00.html
•http://images.google.com.ph/imgres?imgurl=http://executive.govt.nz/minister/maharey/divide/images/fig-1.gif&imgrefurl=http://executive.govt.nz/minister/maharey/divide/03-01.htm&usg=__IQ9PipLjXwHzHU2MdP8YQefs6iI=&h=328&w=460&sz=21&hl=tl&start=3&um=1&tbnid=ozNXpdX5s5uT9M:&tbnh=91&tbnw=128&prev=/images%3Fq%3Dinternet%2Bconnectivity%2Binfrastructure%26hl%3Dtl%26um%3D1
In information technology and on the Internet, Infrastructure is the physical hardware used to interconnect computers and users. Infrastructure includes the transmission media, including telephone lines, cable television lines, and satellites and antennas, and also the routers, aggregators, repeaters, and other devices that control transmission paths. Infrastructure also includes the software used to send, receive, and manage the signals that are transmitted.
In some usages, infrastructure refers to interconnecting hardware and software and not to computers and other devices that are interconnected. However, to some information technology users, infrastructure is viewed as everything that supports the flow and processing of information.
Infrastructure companies play a significant part in evolving the Internet, both in terms of where the interconnections are placed and made accessible and in terms of how much information can be carried how quickly.
The figure below shows the relationships between some of the key entities which make up the internet connection infrastructure.
Some elements of the telecommunications/Internet infrastructure
Local loop: This includes the copper wire pairs that link terminals (commonly telephones) to their nearest exchange but may also in some rural areas include multi-access radio technology.
Internet Service Provider (ISP): The ISP is integral to connection to the Internet. It is the ISP who provides the Internet Protocol (IP) linking services which allow messages to be routed throughout the Internet 'cloud'. Most ISPs will have one or more broadband or high bandwidth connections to the telecommunications backbone which both allows users to connect to the ISP and links the ISP to other IP service providers on the Internet.
Telephone Exchange: Internet connection capacity is normally dependent on the capacity of the link between a user and their local telephone exchange, which will in turn depend on the location and the age and quality of the exchange's equipment. Many Telecom NZ exchanges in rural and congested urban areas were upgraded in the early 1980s and continue to provide good standard telephone services but are not able to provide services and access speeds which are available through a modern exchange.
Backbone: The telecommunications backbone is the network which links exchanges to each other and includes both transmission and circuit switching elements. The transmission elements may include copper and optical fibre cabling, and microwave links. The international circuits also include satellite links. Parts of the existing domestic backbone between some provincial centres may require upgrading to support greater digital data flows.
Technologies Available and in Use
Aside from dedicated fibre-optic and coaxial cable networks and wireless connections, which are available at present, access to the Internet is generally only available over the telephone network. Even for those with satellite connections, the return path from the user to the ISP relies on the telephone network. Thus, in practice for the overwhelming majority, technologies available for Internet connection are limited to those capable of using the copper wire local loop.
Technologies available over the local loop
V90 Modem: This is presently the 'domestic standard' for achieving a data rate of up to 56 Kbps over a standard telephone line. It requires only an inexpensive modem connecting a personal computer to a telephone line, and will support slow-motion video. There are limiting factors, however. A connection speed of 56 Kbps cannot be realised if there is more than one analogue-to-digital conversion in the connection to the ISP and is usually limited to a maximum line length between subscribers and the nearest exchange of 3 to 5 kilometres. In practice this means that for many users access speeds are less than the theoretical maximum. Typically in urban areas 33 Kbps is available but in many rural areas line quality is such that speeds fall well below this. For example, many rural areas are served with multi-access radio technology, which was introduced over ten years ago to eliminate party lines, and can only handle data transfer rates of 9.6 Kbps.
ADSL (Asynchronous Digital Subscriber Line): This is one of a family of technologies referred to collectively as xDSL, a term covering different types of Digital Subscriber Lines. xDSL technologies use sophisticated modulation schemes to pack digital data onto copper wires. xDSL is similar to ISDN (see below) inasmuch as both operate over existing copper telephone lines, but requires short runs to a central telephone exchange (about 2 kilometres). Potentially, xDSL offers broadband level speeds - up to 32 Mbps for downstream traffic, and from 32 kbps to over 1 Mbps for upstream traffic.
ADSL is offered by Telecom NZ to subscribers as JetStream. It is capable of speeds of up to (but generally much less than ) 6 Mbps in one direction and a much lesser speed in the other. It is currently available only in the main centres but is slated to be rolled out progressively throughout the country and is displacing ISDN (see below). However, this may be slow (after almost 20 years, ISDN still does not reach into most of rural New Zealand). Given that even inner city suburbs in areas such as Wellington cannot presently be serviced with ADSL, some further technology development will be required before ADSL can provide a widespread solution to bandwidth limitations, especially in rural areas.
ISDN (Integrated Services Digital Network): Telecom provides ISDN in all the main centres as well as many of the smaller centres, however, with one or two exceptions it is not generally available in rural areas. The technology supports data transfer rates of from 64 Kbps to 2 Mbps. Basic Rate ISDN installations provide the equivalent of two standard telephone lines. One can be used for voice and the other for data, or both lines can be used to achieve data rates of 128 Kbps. This is just adequate for two-way video applications such as distance learning and video-conferencing. Multiple ISDN lines can be used to obtain higher quality connections, for example, three ISDN lines provide a connection speed of 384 Kbps and this is typically used where video quality is critical, for example for tele-medicine applications. Telecom NZ has demonstrated a reluctance to make further investment in its ISDN infrastructure, promoting ADSL services as a preferred alternative.
Frame Relay: This is available from 64 Kbps and is easily scalable up to 2 Mbps. Frame relay is generally used as a dedicated point-to-point service or as a virtual private network and has the advantage of fixed price tariffs (no usage charges). The technology is specially suited to applications where guaranteed bandwidth is required such as for voice and video applications.
Asynchronous Transfer Mode (ATM): This technology offers very high bandwidth, up to 150 Mbps and is typically used for linking corporate networks.
IP Networking: This is a new family of services being piloted by Telecom NZ which is specially suitable for Internet connections where dedicated bandwidth is not critical. The focus is on flexibility and interconnectivity between a variety of connection services, such as dial-up telephone, ISDN and frame relay.
Rural issues with the local loop
While in some urban areas high bandwidth and even broadband access speeds are available, telephone subscribers more than 3 to 5 kilometres from an exchange are limited to access rates of 33 Kbps or less. In addition there are major problems with line quality reported for rural subscribers. A recent survey conducted for MAF reported 54% of rural subscribers as having problems affecting telephone lines including noise, electric fences (often a problem of poor fence installation by the farmer) and exchange overload. Telecom NZ reports that only 5% percent of local loop lines are not capable of maintaining a reliable data speed of 14.4 Kbps. The overwhelming majority of these would be in rural areas and thus this figure represents a large proportion of rural subscribers.
An indicator of insufficient infrastructure capacity is the number of reported problems with obtaining a second or third telephone line (an obvious way of trying to bypass the data rate bottleneck). Over one third of survey respondents who indicated that they had attempted to get a second line failed to do so.
Reference:
•http://en.wikipedia.org/wiki/Telecommunications
•http://images.google.com.ph/imgres?imgurl=http://www.window.state.tx.us/tspr/alamoccd/ex8-19.gif&imgrefurl=http://www.window.state.tx.us/tspr/alamoccd/ch08c.htm&usg=__QFFE6JleZKYmdBSFMxH9KzOBsc0=&h=873&w=762&sz=24&hl=tl&start=13&um=1&tbnid=h6u3xK_4vRUjgM:&tbnh=146&tbnw=127&prev=/images%3Fq%3Dinternet%2Bconnectivity%2Binfrastructure%26hl%3Dtl%26um%3D1
•http://searchdatacenter.techtarget.com/sDefinition/0,,sid80_gci212346,00.html
•http://images.google.com.ph/imgres?imgurl=http://executive.govt.nz/minister/maharey/divide/images/fig-1.gif&imgrefurl=http://executive.govt.nz/minister/maharey/divide/03-01.htm&usg=__IQ9PipLjXwHzHU2MdP8YQefs6iI=&h=328&w=460&sz=21&hl=tl&start=3&um=1&tbnid=ozNXpdX5s5uT9M:&tbnh=91&tbnw=128&prev=/images%3Fq%3Dinternet%2Bconnectivity%2Binfrastructure%26hl%3Dtl%26um%3D1
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