Digital Object Architecture: Building Information

Transcript:Digital Object Architecture: Building Information:
Digital Object Architecture: Building Information Management Infrastructure for Networks 20 September 2010 Larry Lannom Corporation for National Research Initiatives http://www.cnri.reston.va.us/ http://www.handle.net/ Three Initial Networks About 30 – 35 years ago, DARPA funded the creation of three seminal packet networks – ARPANET, Packet Radio, Packet Satellite The Internet came about from a desire to link the three of them Ethernet occurred in parallel, led by Xerox Parc researchers, and other network types followed The resulting architecture was independent of the number and type of networks or who ran them. The Internet would be a global information system. An open-architecture would be used to combine different networks based on open and well-known interfaces, protocols & objects. A new communications-oriented host protocol (TCP/IP) would be created to replace the original ARPANET host protocol (NCP). The concept of global addressing and IP addresses would be introduced to identify individual machines anywhere on the global Internet. Key Decisions Comments on the Key Decisions The architecture is robust in the presence of many different network types and many outages. Gateways provided IP routing and Network "Impedance Matching". TCP accommodated end-end protocol: different packet sizes, duplicates, error detection, losses due to tunnels, mountains, jamming, etc. Separate network administrations were permitted, which allowed the Net to grow. DNS not technically critical, but helped users. Understanding the Big Picture Many things were done well from the outset; with 20/20 hindsight, some could have been done better. The context was critical: Mostly mainframes, few time-sharing systems No PCs, workstations, LANs One dominant carrier in the US Government facility initially What is important at the time may be only apparent with hindsight; but also what seems important at the time may not turn out to be so important later on. What is so hard about it? Making it scalable over platforms, size and time Achieving Critical Mass Getting Buy in: Pleasing many essential participants Displacing prior capabilities Structuring matters to deal with concerns about empire building It’s a lot easier to create brand new capabilities than to affect existing means of operation. Infrastructure Development Infrastructure Creation is a Subtractive Process Infrastructure reduces a common, shared capability to its basic and essential attributes. These attributes are not always recognized or understood up front. Upon further scrutiny, capabilities are usually deleted from a well-conceived architecture over time. Consensus develops when no more can be removed without disabling the infrastructure. What is the Information