by Jeff Carrell, Electronic Communications Chairman
A topology is the representation of the network's layout. There are a few basic types including: star, ring, star wired and linear bus. Of these, the most commonly deployed topology today is the star wired.
In a star topology, there is a central device to which all nodes are connected. The central device polls each connected node and allows that node to communicate its information for the destination node to the central computer which stores that data until it communicates to the destination node and can pass the data on. The most common type of star topology is the mainframe and terminal type systems. These have been deployed all over the world for many years, and there are still many of them in service today.
A ring configuration has all nodes connected to each other in a series; in to an out, and the two end points also connecting each other. Unfortunately, this design makes for a very difficult cabling plant, so it was never really implemented on a large scale. There were a few proprietary systems marketed this way. The better design called for a star wired ring.
A star wired ring affords the same function of the ring communication, while allowing a much better designed and implemented cable plant for the network. The basic function of a ring is that every node, whether PC or server, gets an equal time to communicate on the network. The design of the ring also provides some self-healing properties in the case of the IBM Token Ring system. Token Ring is the most widely deployed star wired ring topology.
Many folks who have worked with coax based Ethernet will be familiar with this topology. The linear bus has two finite end points (meaning the ends don't connect together as in the ring topology). Therefore, in order to connect each node into the network, you have to daisy chain the cable from one to the next. The actual connection is only broken at the NIC, and each cable end is connected to a "T" connector, which then connects to the NIC. This topology was once the most prominently deployed, however, over the years, network support personnel encountered major headaches when the cables were disconnected at the T connector, instead of at the NIC.
Since the mid to late 1980's, the star wired topology has been the most popular deployed technology. Since this topology is configured in a spoke or star of spokes configuration, Ethernet and token ring networks can use the same cable plant. IBM first used the star wired configuration for its token ring network technology during the mid 1980's. In late 1989, 10BaseT (twisted pair Ethernet) was standardized. This provided network designers the capability of forming structured cabling systems, and then deciding which network technology to run over it. Today, almost every new network technology runs over a star wired topology configuration.
| Star | Ring | Star Wired | S. W. Ring | Linear Bus | |
|---|---|---|---|---|---|
| 10Base2 | - | - | - | - | X |
| 10Base5 | - | - | - | - | X |
| 10BaseT | - | - | - | X | - |
| 10BaseFL | - | - | - | X | - |
| 100BaseTX | - | - | - | X | - |
| 1000BaseT | - | - | - | X | - |
| Token Ring | - | - | X | - | - |
| FDDI | - | - | X | - | - |
| ATM | - | - | - | X | - |
| ARCnet | - | - | - | X | - |
| LocalTalk | - | - | - | - | X |
| IBM 3270 | X | - | - | - | - |
| IBM 5250 | X | - | - | - | - |
| Gateway Comm G-Net | - | - | - | - | X |
| ProNET10 | - | - | X | - | - |
| ProNET80 | - | - | X | - | - |
| AT&T StarLAN | - | - | - | - | X |
| Corvus Omninet | - | - | - | - | X |
| Novell S-Net | X | - | - | - | - |
| IBM PC Network | - | - | - | - | X |
Copyright © 1997 Jeffrey L. Carrell All Rights Reserved
by Dan Benigni, Chairman USAB
The new Bylaws for IEEE-USA will take effect on January 1, 1998, and what is now known as "IEEE United States Activities" (IEEE-USA) will become "IEEE United States of America." What does this change mean to you - the US members of the IEEE?
The new Bylaws were written to: (1) make USAB a more autonomous, self-governing IEEE entity; and (2) end the practice of the VP of Professional Activities automatically assuming the role of USAB Chair - some basic, but important, objectives.
The real historical significance is that for the very first time, you, and not the IEEE Assembly, will decide who is going to lead IEEE-USA. [Note: currently, when the Assembly chooses the VP for Professional Activities, there is no guarantee that the leader of IEEE-USA will be a US citizen.]
This is your opportunity to make your IEEE vote count as never before, since the first few Presidents of IEEE-USA that you elect will set the tone for the future of the organization. Pay close attention to their campaigns, to their ideas for the future, and to their commitment to positive change (look for candidate profiles in August Perspectives - insert to The Institute).
This year you will be asked to vote for the 1998 IEEE-USA President, the President-Elect, a 1998 Member-at-Large (one-year term), and a 1998-99 Member-at-Large (two-year term). In future years, you will be electing only the President-Elect and the two-year Member-at-Large.
The President of IEEE-USA will now unequivocally speak only for IEEE members in the United States. When that person speaks to Congress, to the White House, to the media, or to industry, he or she will be speaking for you more directly than ever before. The President of IEEE will still represent the global/transnational organization, and the two should not be confused.
(attributed to William Safire)
Our Technical Society Chapters are reporting new officers for 1997-98:
The advantages are: you get easily accessible, up-to-date information and we save time and money that can used to support other member programs. To subscribe, send a message to either j.carrell@ieee.org or j.eason@ieee.org. For now, you will be receiving both the print and email newsletters. In the future, you can help us save some trees.
UTILITY RESTRUCTURING LEGISLATION PREDICTED - House Commerce Energy and Power Subcommittee should pass legislation to restructure the electric-utility industry by the end of the month according to Rep. Dan Schaefer, R-Colo., in comments to the attendees of IEEE-USA's symposium on the role of the Federal government in restructuring the electric power industry. Schaefer, who chairs the subcommittee, also told the group that he expects the full Commerce Committee to take up the bill in the fall. H.R. 655 would permit consumers to choose their electricity supplier by Dec. 15, 2000. (See September Perspectives for a report on the IEEE-USA symposium, or contact 202-785-0017.)
RESTRUCTURING MEANS MORE THAN SAVING MONEY - IEEE-USA Energy R&D Policy Committee Chair Robert J. Thomas urged federal lawmakers not to lose sight of the technical challenges involved in reworking the nation's complex electric-power delivery system. According to Thomas: "Lower electric bills are small comfort if your lights don't work when you flip the switch. We take the high reliability of our nation's electricity for granted. But can we maintain reliability while creating a national power grid out of many small regional ones, while transmitting power long distances from generating facilities, and while facing pressure to cut costs by reducing research and development? To make restructuring work, legislators, regulators and industry will need to work together with engineers to create a new industry that will deliver electricity reliably, as well as cheaply."
Two senators are proposing legislation (S. 712) to overhaul the entire system of managing classified information, calling for downsizing the amount of secret information and examining and declassifying government documents at specified intervals. The cost of keeping the federal government's secrets was an estimated $5.2 billion in 1996.
Sens. Patrick Moynihan, D-N.Y., and Jesse Helms, R-N.C., are the Senate sponsors. Reps. Larry Combest, R-Tex., and Lee Hamilton, D-Ind., are sponsoring companion legislation in the House.
Moyniham and Helms agree that we must develop "a culture of openness" in the federal government and that the term "secrecy" must be defined by statute. Secrecy, they say, belongs in the realm of national security and "must serve that interest alone."
PETITION CANDIDATE QUALIFIES - Ken Laker has qualified as a candidate in the 1998 president-elect race. Laker, Professor at the University of Pennsylvania, will join Board-approved candidates Donald Bolle, Professor at Polytechnic University and Joel Snyder, PE and consulting engineer, on the ballot. For additional information, see The Institute or IEEE Web site.
LAN/MAN STANDARDS GO ON-LINE - As part of On-Line IEEE Standards
(OLIS) electronic services, the OLIS for Local & Metropolitan
Area Network (LAN/MAN) subscription is available. The annual subscription
includes continuous and unlimited access to over 30 IEEE LAN/MAN
standards, as well as to all new or revised LAN/MAN standards
that become available during the subscription period, at no additional
cost. Users can access the IEEE Standards Web site at j.t.walker@ieee.org.
IEEE-USA's Alliance of IEEE Consultants' Networks (AICN) has produced the 1997 National Directory of Electrotechnology Consultants, one of its ongoing efforts to assist the Institute's self-employed US members.
AICN's second annual national directory includes a listing of more than 400 electrical, electronics, software and management consultants and their services alphabetically, by state and by category - with a listing of specialties. It also supplies readers with a roster of IEEE Consultants' Networks, providing contact information for local referrals, as well as for the coordinating committee.
The 1997 Directory of Electrotechnology Consultants is available free by contacting IEEE-USA's William Anderson; telephone 202-785-0017, or e-mail w.anderson@ieee.org.
Prospective clients can also access a database of consultants on IEEE-USA's Web site at www.ieee.org/consultants. Users can search by name, technical specialty or state.
Motorola Inc., will receive the 1997 IEEE Corporate Innovation Recognition award for its leadership in technology for portable communications equipment. The award will be presented at the Institute's annual Honors Ceremony on 28 June in Cleveland.
The company will be honored for its "leadership in research, development and deployment of high-density electronic packaging and interconnections for portable communications products." IEEE established the award in 1985 to recognize the creation of innovative products or concepts which have resulted in major advancement of the arts and sciences of electrotechnology. Past recipients include Apple Computer, AT&T Bell Laboratories, Bellcore, Ericsson Radio Systems, Hewlett Packard, IBM, Intel, Philips, Sony and Texas Instruments.
William J. Weisz, Motorola's retired chairman of the board and chief executive officer, will accept the award on behalf of the company. Weisz also will receive the IEEE Ernst Weber Engineering Leadership Recognition award for his personal leadership and major contributions in two-way radio and paging systems.
Motorola has been a leader in advanced research and development in circuit design and packaging for portable communications equipment since it introduced hand-held and back-pack radios during World War II. Since then the company has introduced numerous advancements including low-frequency and VHF pagers, fountain pen- and credit card-sized pagers, wrist watches combined with a pager, and miniaturized cellular telephones.
Today, Motorola is designing the system and portable subscriber units for a global satellite wireless communications network designed to serve hand-held telephones and permit voice, data, fax or paging messages to reach their destinations almost anywhere on earth.
It's the start of a New Year for the Section and I am honored to be your choice as Chairman. I have a lot of confidence in the Executive Committee you have elected: we will work hard to represent you, the members, to the Region and provide the best programs and services available. To accomplish this, I am asking you for some help.
The Executive Committee needs your input. The only way we can bring you the programs and services you want is for you to tell us what you need. The free flow of communication is vital to the success of our and your goals.
I will use this column to communicate the Sections plans and goals to you. Please use what ever means necessary to communicate your needs and goals to me. I will make every effort to help you accomplish these. The IEEE is a large and diverse organization with many resources at its disposal. The Section and its Chapters can and will use these resources to serve the needs of our members. Feel free to contact me at b.geisel@ieee.org or any of the Section and Chapter officers with concerns, ideas, criticisms, or questions.
--Bob Geisel
Signals is inviting all Section members with a flair for writing to submit articles on technology or professional topics of interest for publication in the newsletter. Contact j.eason@ieee.org with submittals or for information.
Recognizing our Section members for their long-time commitment to the profession on the anniversary of their joining IEEE.
45 yrs
35 yrs
If the puzzle you solved before you solved the puzzle you solved after you solved the puzzle you solved before you solved this one was harder than the puzzle you solved after you solved the puzzle you solved before you solved this one, was the puzzle you solved before you solved this one harder than this one?
Answer to last month's Brainbuster:
In general, the sum of the integers from 1 to n is n(n + 1) / 2. So, the sum of integers from 1 to 100 is 5050.
Jean Eason, Editor