پول باران (و. 29 أبريل 1926 - 26 مارس 2011) هوأحد مخترعي شبكات تحويل الطرود بالاشتراك مع دونالد داڤيس وليونارد كلاينروك. وكانت أفكار مماثلة لشبكة البيانات الموزعة يتم العمل عليها بشكل مستقبل بواسطة دونالد داڤيس في معمل الفيزياء الوطني في المملكة المتحدة، بالرغم من حتى داڤيس كان يهتم بصفة أساسية بمشكلة تقاسم الموارد أكثر من باران الذي كان يركز على القضايا العسكرية.

حياته المبكرة

ولد باران في گروندو، پولندا، لكنه نشأ في بلاروس. انتقلت عائلته إلى فيلادلفيا عام 1928. تخرج من جامعة دركسل وحصل على شهادة الماجستير في الهندسة من UCLA عام 1959، وبدأ في العمل في مؤسسة راند في العام نفسه.

تصميم شبكة تحويل الطرود

أثناء عمله في مؤسسة راند، اضطلع پول باران بمهمة تصميم نظام اتصالات a "survivable" that could maintain communication between end points in the face of damage from nuclear attack. At the time, most American military communications used HF connections which could be put out of action for many hours by a nuclear explosion. Baran decided to automate RAND director Collborn's previous work with emergency communication over conventional AM radio networks and showed that a distributed relay node architecture could be survivable. The Rome Air Development Center soon showed that the idea was practicable.

Using the mini-computer technology of the day, Baran and his team developed a simulation suite to test basic connectivity of an array of nodes with varying degrees of linking. That is, a network of n-ary degree of connectivity would have n links per node. The simulation randomly 'killed' nodes and subsequently tested the percentage of nodes who remained connected. The result of the simulation revealed that networks where n ≥ ثلاثة had a significant increase in resilience against even as much as 50% node loss. Baran's insight gained from the simulation was that redundancy was the key.

After proving survivability Baran and his team needed to show proof of concept for this design such that it would be able to be built. This involved high level schematics detailing the operation, construction and cost of all the components required to construct a network that leveraged this new insight of redundant links. The result of this was one of the first store-and-forward data layer switching protocols, a link-state/distance vector routing protocol, and an unproved connection-oriented transport protocol. Explicit detail of these designs can be found in the complete series of reports "On Distributed Communications", published by RAND in 1964. The design flew in the face of telephony design of the time, placing inexpensive and unreliable nodes at the center of the network, and more intelligent terminating 'multiplexer' devices at the endpoints. In Baran's words, unlike the telephone company's equipment, his design didn't require expensive 'gold plated' components to be reliable.

بيع الفكرة

After the publication of On Distributed Communications, Paul Baran presented the findings of his team to a number of audiences, including AT&T engineers (not to be confused with Bell labs engineers, who at the time provided Paul Baran with the specifications for the first generation of T1 circuit which he used as the links in his network design proposal). In subsequent interviews Baran mentions how his idea of non-dedicated physical circuits for voice communications were scoffed at by the AT&T engineers who at times claimed that Baran simply did not understand how voice telecommunication worked.

As a result of President Eisenhower's Defense Reorganization Act of 1958, there was a major shift in leadership in the Pentagon around the time Baran's work was accepted by the US Air Force and DoD for implementation and testing. When Baran discovered an older Navy admiral would oversee the project he decided the project would be better off sitting on the shelf as reference material, claiming that an 'old analog guy' couldn't grasp what it was the project aimed to accomplish, and thus would likely fail from lack of understanding.

Around the same time when ARPA was developing the idea of an inter-networked set of terminals to share computing resources, among the number of reference materials considered was Paul Baran and the RAND Corporation's On Distributed Communications volumes. The ARPANET was never intended to be a survivable communications network, but some still maintain the myth that it was. Instead, the resilience feature of a packet switched network that uses link-state routing protocols is something we enjoy today on the Internet in some part from the research done to develop a network that could survive a nuclear attack.

أعماله المتأخرة

Baran also provided a spark of invention to four other important networking technologies. He was involved in the origin of the packet voice technology developed by ستراتاكوم at its predecessor, Packet Technologies. This technology led to the first commercial pre-standard ATM product. He was also involved with the discrete multitone modem technology developed by Telebit, which was one of the roots of Orthogonal frequency-division multiplexing which is used in DSL modems. In 1985, Paul Baran founded متريكوم, the first wireless Internet company, which deployed Ricochet, the first public wireless mesh networking system. He also founded Com21, an early cable modem company. Following Com21, Baran founded GoBackTV, which specializes in personal TV and cable IPTV infrastructure equipment for television operators. Most recently he founded Plaster Networks, providing an advanced solution for connecting networked devices in the home or small office through existing wiring. In all cases, Baran provided early ideas and gave credibility to strong groups of developers who then took those ideas far beyond his original spark.

Paul Baran also extended his work in packet switching to wireless-spectrum theory, developing what he called "kindergarten rules" for the use of wireless spectrum.

وبالاضافة لابداعاته في منتجات التشبيك، فيُنسب إليه اختراع كاشف المعادن المستخدم في المطارات.^[]

جوائز وتكريمات

• 2009 UCLA Engineering Alumnus of the Year
• National Medal of Technology and Innovation, 2007
• Bower Award and Prize for Achievement in Science (2001)

المصادر

• Baran, Paul (1964), On Distributed Communications, Rand, Archived from the original on 2006-06-15, http://replay.waybackmachine.org/20060615000308/http://www.rand.org/about/history/baran.list.html 
• entry
• Brand, Stewart (March 2001), Founding Father, Wired.com, http://www.wired.com/wired/archive/9.03/baran.html 

وصلات خارجية

• Paul Baran Invents Packet Switching - Living Internet
• 44-page oral history interview with Paul Baran. Charles Babbage Institute University of Minnesota, Minneapolis. Baran describes his working environment at RAND, as well as his initial interest in survivable communications, the evolution of his plan for distributed networks, the objections he received, the writing and distribution of his eleven-volume work, "On Distributed Communications." Baran discusses his interaction with the group at ARPA who were responsible for the later development of the ARPANET.
• Founding Father Wired, Issue 9.03 Mar 2001, (interview with Paul Baran, exploring the background to Baran's work at RAND on survivable networks).
• Wireless Communications and Computing at a Crossroads, Journal on Telecommunications & High Technology Law, Vol. 3, No. 2, p. 239, 205 (describing Paul Baran's development of packet switching and its application to wireless computing).
• Transcript of a keynote address he gave in 2000 including a photo
• Reliable Digital Communications Systems Using Unreliable Network Repeater Nodes
• Paul Baran, Internet and packet switching pioneer, is mourned