by Jeff Carrell, Electronic Communications Chairman
In the September issue of Signals, I discussed TCP/IP.
IPX was designed by Novell and is a derivative of an older networking protocol by XEROX called XNS. IPX has turned into one of the most prominent network protocols, primarily due to the shear volume of Novell NetWare LANs. Moreover, IBM, Microsoft, LANtastic and other lesser known NOSs have designed their systems so that IPX could be used in addition to their own proprietary protocols.
IPX uses an 8 digit, hexadecimal numbering system, where any numbers between 00000001-FFFFFFFE are valid. Each network segment is assigned a number by the network engineer or system administrator. Each network segment must have a unique number, and no two network segments that are connected in way can have the same number. Occasionally, you'll find IPX network numbers forming names, such as: da11a5, f005ba11, badf00d and many others.
The IPX address of an individual device is the IPX segment address appended with the NIC MAC address, in the form of: dalla5:0268c14532dc.
Every NIC in a file server that has workstations connected to the same hub, switch or router is a network segment. In the case of a NetWare based file server, even the OS internally has an IPX segment number assigned to it, even though no actual devices communicate on the internal interface. This internal segment address deals with server to server communications.
Although IPX is a very robust and fast performing protocol on a LAN, it does slow down and incur extra overhead when traveling over slower speed WAN links. Novell designed an additional protocol called Packet Burst, optimized for use when communicating over WAN links.
NetBIOS is the primary protocol used by IBM LANs. IBM designed the protocol for their original network operating system, but it was designed in the days of small networks and is not a fast nor extensible protocol. NetBIOS is not routable, therefore if multiple networks need to connect together, there are only a few options. The networks either have to be bridged together, another protocol has to be used by all devices on all networks, or a special form of moving the NetBIOS information must be used - called "tunneling."
Although still in use by IBM based networks today, more network engineers and managers are opting for more easily deployable protocols like TCP/IP or IPX. One benefit however is that NetBIOS has no numbering or naming convention that has to be configured. All the devices on the network simply use the MAC address of the NICs in order to communicate together.
NetBEUI was designed by Microsoft and is their primary protocol for their NOSs. NetBEUI is a derivative of NetBIOS with a few additional capabilities. It follows the same basic operations and has the same pitfalls. Unfortunately, NetBEUI is also not routable which has presented many network engineers and managers with formidable issues of late.
Some router vendors provide tunneling capabilities for NetBIOS or NetBEUI protocols in their products. The basic function of tunneling is taking the initial NetBEUI or NetBIOS protocol based packet to be received by the router port, wrapping it an IP packet, providing the "from" and "to" router port addresses in the new IP packet, and then sending it on. The receiving router port takes the packet, notices that it has a special signature, decrypts the embedded NetBEUI or NetBIOS packet inside and then sends it on in that native format. Unfortunately, there is some overhead to this function, but if you really need to "route" these two protocols, it is possible.
Networking capability has been engineered into all Apple Computer products since the very first Macintosh. Apple wanted the networking of their computers to be inexpensive compared to other computer and networking products available during those times (1984), so they developed AppleTalk.
AppleTalk has three basic numbering components: the network address which uses numbers between 0-65535, the node address using 0-255 and the socket address (used by applications) using 0-255. Additionally, there is the capability of assigning a alphanumeric name to a network address range or group of network address ranges, called the Zone Name.
There have been two major releases of AppleTalk, the original referred to as AppleTalk Phase I, and in 1990 Apple released AppleTalk Phase II. AppleTalk Phase II supported larger networks and more sophisticated AppleTalk routing capabilities. As networking technology advanced, Apple started supporting TCP/IP and IPX on their computers.
Copyright © 1997 Jeffrey L. Carrell All Rights Reserved
by Julie Sheridan-Eng, Women in Engineering Committee
Lisa Ann Petrides presented the results of her Ph.D. thesis work on the gendered construction of engineering graduate schools at the IEEE Women in Engineering Forum in Cleveland in June. Dr. Petrides surveyed over 1000 engineering graduate students in five engineering concentrations at a large engineering research university and conducted 21 in-depth interviews as follow-ups to her surveys.
Dr. Petrides noted, "What was surprising was how remarkably similar the women and men were [upon entering graduate school], in what they brought to the table and what they expected out of their graduate careers." Both women and men expressed interest in and aptitude for math and science at an early age. They came from similar social and class backgrounds, and both genders felt they had been encouraged in their endeavors by their parents. They had equivalent GRE scores and GPAs. However, many men felt that women were admitted to the graduate school with lower qualifications.
One striking difference reported by the men and women was the time at which they decided to pursue engineering. The men typically decided before entering undergraduate school to study engineering, while women decided in undergraduate school.
Dr. Petrides found the highest percentage of women in the departments with the fewest number of students. For example, in electrical engineering, which was the largest department, women comprised 9.7% of the graduate population, whereas in industrial and chemical engineering, which were the smallest departments, women comprised 24% and 27% of the graduate population.
She also asked each survey respondent to rank order the perceived prestige and status of each engineering discipline, and found that women are in greater numbers in the concentrations with the least perceived status. She also noted that women are least likely to go into the engineering disciplines for which they have the most salary parity with men.
During their graduate school experience, men and women showed many similarities. They seemed to like and dislike the same subject matter. They expressed similar approaches to problem-solving.
However, effects due to gender differences were raised by both men and women. Men commented that the culture changed when a woman was introduced to their group. Several men expressed frustration in knowing how to deal with women in their groups. One man commented, "We were falling all over ourselves to try to make them fit in." The men also demonstrated assumptions about what was gender-appropriate behavior, such as what jobs a woman should do or how a woman should act or dress.
The women surveyed were less likely than the male counterparts to participate in social activities with their peers. They were less likely to have mentors and role models. The women felt that they were treated differently by their male colleagues, and that the men had strong stereotypes about women.
Another major difference included the reasons for considering leaving graduate school. Men primarily listed that they had been offered a job, could earn more money, or had decided to change careers. Women listed isolation as the primary reason for considering leaving, and that they would search for a profession in which they felt more comfortable.
One question asked, "Have you ever experienced discrimination in graduate school?" 63% of the women said no, never; 20% said yes; and 17% said not really discrimination, but I have been made to feel uneasy or uncomfortable by subtle comments and actions. The men's responses to the same question included: 85% had never experienced discrimination; 5% said yes, and were racial minorities; and 10% said yes, due to reverse discrimination.
In terms of their outlook on their job prospects, men and women had similar expectations of the salaries they would receive and of the time commitment their job would require. They both expressed that status of their jobs as engineers and as Ph.D.'s was important to them. They had similar expectations as to job type or sector of work, and both men and women felt that it was important that their work benefit society.
Major differences among men and women regarding their future employment centered around the perception about opportunities. Men felt that women have many more opportunities to get jobs and to be promoted, while women felt they had fewer, or had to work harder to get the same opportunities.
Dr. Petrides summarized by saying that although the men and women entering engineering graduate school had very similar backgrounds, experiences, and expectations, "the learning environment becomes sexualized when women are expected to conform to norms of stereotypical gender-appropriate behavior." This environmental sexualization prevents the full inclusion of women into the engineering graduate school environment.
Dr. Petrides has several suggestions for engineering graduate schools to improve the climate for women students. They include:
A petition is being circulated to organize a new Chapter of the Industry Applications Society in the Fort Worth Section, to provide the members with another forum for technical information and continuing professional development. Twenty-five signatures of local IAS members are required. Ed Worley, P.E. will be leading the effort - contact him at 817-738-0630 for a copy of the petition.
Ed plans several meetings this year focusing on technological
advances and current engineering practices and standards in the
areas of interest in IA: engineering of applications for commercial
and industrial electrical utilization machinery and equipment,
including electrical/electronic controls, electrical power distribution
and grounding on the premises of a facility or plant, variable-frequency
drives for motors, and more. Watch Signals for updates.
AAES' ENGINEERING WORKFORCE COMMISSION REPORTS SAT Math scores may be up but engineering enrollment is coming down according to a survey of the Class of 2001 by the College Board. Despite the infotech revolution, only 8% of incoming college freshman chose engineering as their intended major down from 11% ten years ago. Problems remain for women in engineering - less than 1 out of 5 engineering freshman will be women according to the survey.
Perhaps the National Academy of Engineering has a solution, though. With a major gift from AT&T, the NAE will be celebrating achievements of women in engineering. "Women in Engineering: Dispelling Myths, Profiling Achievement" will kick off in 1998 as a series of conferences that will bring together women who are on the vanguard of the engineering profession. An Internet site will highlight conference proceedings.
by Bob Bellinger, EE Times
Exciting things are happening at IEEE-United States Activities, the American unit of the worldwide technical society that you all know and love.
For years, the IEEE grappled with its split personality of serving as the American engineer's chief voice in Washington and acting as a technical organization for the rest of the world. It dealt with that by setting up IEEE-USA with its own funding (a $23.50 assessment in addition to IEEE dues), its own offices and own staff.
Now, under a reorganization, the United States Activities unit is being told: it's time to cut the purse strings. No more hikes in the USA assessment. From here on, you've got to be more entrepreneurial.
And so this year, IEEE-USA is taking its first steps toward a semi-autonomous, not-quite-independent status.
As encouraging as those developments are, no one is taking them lightly. For IEEE-USA to be effective, it's got to bring in some significant money. The assessment will carry the group for the next few years, but without new money, IEEE-USA could face considerable downsizing.
Contrary to what some members have thought, IEEE-USA's greatest hurdle hasn't been the opposition of other IEEE technical societies, who've opposed USA's professional slant and easy funding. The principal hurdle IEEE-USA faces is apathy, either from its own members or from the two-thirds of the EE Times readership who don't belong.
Unseen, unyielding, unheard from, apathy represents a massive bog through which the future IEEE-USA officers will have to wade forward, one sloggy step at a time. Today's Engineer is promising; Lessard is breathing fresh air into the "old boys club" of PACE. And an elected president may give USA an independent voice.
Position papers won't cut it. Engineers are bottom-line, cut-to-the-chase professionals. IEEE-USA has to "show them the worth."
Or get stuck in the muck.
STUDENT MEMBER DUES REDUCED - Beginning 1 September 1997 for the 1998 calendar year, IEEE Student membership dues will be $19.00.for Regions 1-6 (United States). Also included is a 50% reduction on all Society memberships and a 25% reduction on optional society publications. Student Members with no breaks in service are eligible for the Graduated Student Dues Program, allowing recent graduates to pay reduced rates for IEEE and Society memberships over the first 4 years of their professional lives.
Recognizing our Section members for their long-time commitment
to the profession on the anniversary of their joining IEEE.
45 yrs
35 yrs
25 yrs
At Disney World a canal joining two lakes passes over a road on an aqueduct. When a boat goes across, does it increase the load on the aqueduct?
Answer to last month's Brainbuster:
According to Bayes' theorem, the probability that the ball left
in the box is black is 2/3.
Jean Eason, Editor