Musing: On Permananent and Ephemeral Knowledge and Exam Study

Like many tech-​​workers, we need to ingest vast quant­it­ies of know­ledge to get star­ted in our jobs. Without that know­ledge, there is no work­ing in our busi­ness. What is unique, how­ever, is that we con­tinue to ingest know­ledge for the remainder of our careers — often con­sum­ing large por­tions of our per­sonal time and energy. Worse we even get tested on it by sit­ting formal examinations.

How can we man­age this pro­cess to be more effective ?

Recently, Nick Carr pro­gnost­ic­ated that the Internet (via Google et al) is mak­ing us stu­pid. It’s a good enough art­icle, although Nick Carr is a little high minded and journ­al­istic to make real sense to those of us at the coal face of know­ledge working.

But it made me think about know­ledge ingestion.

Knowledge Ingestion

In my tra­di­tional edu­ca­tion, know­ledge was to inges­ted as per­man­ent ‘for life’ basis (some­thing like a mis­sion crit­ical edu­ca­tion). Thus, learn­ing Maths, Biology etc was all taught as if this was the only thing in your life. Of course, it wasn’t. I don’t regret learn­ing these top­ics, but retain­ing this know­ledge for instant and per­man­ent recall has lim­ited value to me. For example, I under­stand Darwinian prin­ciples, and basic bio­logy, but this rep­res­ents less than 20% of the Biology learn­ing I received at school.

As a Network Engineer /​ Architect /​ Designer (1), I need to ingest know­ledge con­stantly and in large quant­it­ies. Depending on the pro­ject, I can spend up to 14 hours a day read­ing and research­ing inform­a­tion. When I am design­ing a new tech­no­logy, I must work through large quant­it­ies of mater­ial before extract­ing those nug­gets that solve the design prob­lem. This requires a dif­fer­ent tech­nique to what I was taught at school and university.

Experience has taught me that most of this inform­a­tion is not rel­ev­ant or prac­tical. Indeed, the abil­ity to win­now through inform­a­tion and extract rel­ev­ant mater­ial is a skill in itself, but the real key is to work out what you need to learn and what you need to be able to ref­er­ence if you need it later.

This Definition of Learning

There are two parts to this defin­i­tion of learn­ing, memory and comprehension.

Memory Learning means that you have remem­ber a cer­tain of core facts and understanding.For example, I have have mem­or­ised inform­a­tion about how NetFlow con­tains pro­tocol flow inform­a­tion, the dif­fer­ent record types, and that IOS needs configuration.

Comprehension means that I under­stand the applic­a­tion of the inform­a­tion. Thus, NetFlow can be used for per­form­ance ana­lysis, intru­sion /​ threat detec­tion, and so one.

So learn­ing that 2+2=4 is good know­ledge, but learn­ing that “doub­ling the memory in my com­puter will improve sys­tem per­form­ance” is comprehension.

Anything else I can get by doing research when I need it.

Obsolescent and Ephemeral Knowledge

Therefore a cer­tain amount of know­ledge is eph­em­eral, and will be of no use. For example, con­fig­ur­ing ISDN net­works was vital to me a few years ago. Now, I can barely remem­ber the com­mands or pro­cesses to do ISDN.

Obsolescent is know­ledge that you no longer need. Ephemeral know­ledge is when I would research what I need to know. The Internet means that Ephemeral know­ledge is always to hand.

Identifying Permanent and Ephemeral Knowledge

Let me try an example.

When I first star­ted out in net­work­ing, books, train­ing courses and edu­ca­tion were vary rare, and I (wrongly) got very focussed on learn­ing the com­mands that con­figured a router to allow rout­ing. I kept con­fig­ur­a­tions from IOS routers and referred to them as ref­er­ence. I could ‘munge’ the con­fig­ur­a­tions that I had gathered with my exper­i­ence to get the next net­work con­figured cor­rectly. Which was OK, I got the job done, but I didn’t always under­stand why.

It was only much later that I learned how IP for­ward­ing actu­ally worked. That the router examined the IPX or IP header, con­sul­ted the rout­ing table and then for­wared the packet out of the inter­face. And later still, under­stood the dif­fer­ence between pack­ets and frames.

The eph­em­eral know­ledge is the con­fig­ur­a­tions that I kept in text files. The per­man­ent know­ledge is how a router (any router) worked to for­ward a packet, and how that packet was con­struc­ted so that the router had valid information.

For those of us who work on mul­tiple vendors, you should eas­ily under­stand this idea. Permanent know­ledge remains valid on any type of router, Nortel, Vyatta or Cisco doesn’t really mat­ter. Getting to grips with the Vyatta inter­face is eph­em­eral know­ledge and can be found when needed.

Ephemeral know­ledge can be come Permanent know­ledge. If you need to work on Vyatta for an exten­ded period, you will start to mem­or­ise func­tions and inter­face com­mands. The same applies to the CCIE Lab exam. Part of the out­comes for people who pass, is that they are pro­fi­cient in the IOS inter­face. Also the Cisco web site and manuals.

Ability to Learn from Computer

One of the other tricks I have had to learn is how to read from a com­puter screen. I ended devel­op­ing this into a full post­ing and you can read it here

My tra­di­tional edu­ca­tion con­sisted of text­books and black­boards. Working on a DEC PDP-​​11 with punch cards doesn’t really count as ‘com­puter time’. I was also taught how to read a book, absorb inform­a­tion, and to pro­cess that inform­a­tion. In fact, this is so vital to most edu­ca­tion sys­tems that most people don’t even under­stand that your ‘mind’ has been effect­ively ‘pro­grammed’ to ingest know­ledge from a book or paper medium.

In the 1980’s and 1990’s, all com­puters came with an enorm­ous prin­ted manual. Computer rooms had entire book­shelves devoted to Operating Systems and Software manu­als. When we wanted to learn some­thing, we got the manual from the shelf and star­ted read­ing. Successful com­pan­ies had good manu­als, bad com­pan­ies usu­ally did not. (2)

Then, we star­ted to see the doc­u­ment­a­tion on CD from Cisco, Nortel and DEC /​ Digital Equipment. So when I star­ted some­thing new, I would often print the entire manual, then read. Depending on the qual­ity and the what I needed to do, the manual might get a deep read­ing, or more a scan­ning over to absorb the information.

And that was fine until I star­ted trav­el­ling. Carrying sev­eral kilos of papers wasn’t much fun so I star­ted to read the CD ver­sions. It was slow and gradual, but the CD’s were port­able and updated reas­on­ably often. Certainly much more often than the prin­ted ver­sions were. Errors and omis­sions were fixed much more quickly. In the field I could quickly get to the documentation.

Then the doc­u­ment­a­tion switched to being online. Cisco was very early to put­ting their doc­u­ment­a­tion online. This led to them provid­ing sample con­fig­ur­a­tions and design doc­u­ments. This was a real advance, as we could tap dir­ectly into the col­lect­ive wis­dom of Cisco resources, instead of hav­ing to exper­i­ence ourselves in a project.

A few years back I made a decision not to print any­thing that I needed to read. I would force myself to read it online.

It has been pain­ful, like most forms of learn­ing. At the start my con­cen­tra­tion span was much reduced, but over time I am get­ting bet­ter at pro­cessing inform­a­tion dir­ectly from the com­puter screen.

Occasionally, I will still print a sec­tion of manual, say twenty or thirty pages of the cer­tain core concept mater­ial. In the case of Cisco IOS doc­u­ment­a­tion, it is abso­lutely worth read­ing the Introduction sec­tion to a topic, because you can get a good over­view on the ‘thing’ there.

First Principles

Some people call per­man­ent know­ledge ‘first prin­ciples’. I think this is what tra­di­tional edu­ca­tion taught us, and you need to extend this concept. Its too simple.

The idea of ‘fun­da­ment­als’ or ‘basic prin­ciples’ is a good start­ing point, but it isn’t a fluid enough defin­i­tion. It needs to encom­pass broader con­cepts as well as core facts and con­structs. Knowing the 2+2=4 is a basic prin­ciple. But know­ing that a Proxy Server be deployed using WCCP, bridging or in expli­cit mode is also fun­da­mental. You don’t need to really under­stand WCCP until you actu­ally do it, but know­ing that it inter­cepts and redir­ects traffic might be enough for you to get by (but make sure that you research it when you need to design it in more detail)

Successful Learning — an example

So I believe that key to learn­ing is to identify eph­em­eral and per­man­ent top­ics. The things that will help be suc­cess­ful at work is the abil­ity to retrieve per­man­ent know­ledge, and innov­ate on that know­ledge. Let me try a simple example.

I was in a design meet­ing, and the dis­cus­sion was how to improve browser to server response time. Having done some pro­tocol ana­lysis I noticed that a sub­stan­tial amount of traffic was SSL encryp­ted. In turns out that SSL is enabled on the web serv­ers to over­come prob­lems with Microsoft (so-​​called) Internet Explorer secur­ity, and that the browser received more than 50 per­cent of the traffic in SSL encryp­ted form.

My per­man­ent know­ledge is an under­stand­ing of the SSL encryp­tion pro­cess. The SSL pro­cess is very CPU intens­ive when hand­ling the asym­met­ric key exchange and inserts a few seconds of delay in the ini­tial con­nec­tions. It doesn’t show up in some cli­ent test­ing suites so the developers usu­ally don’t see.

A bit of fast think­ing and you can see that by off­load­ing the SSL to a hard­ware load bal­an­cer (F5 LTM or Cisco ACE, say) with a ded­ic­ated SSL co-​​processor should be able reduce this SSL estab­lish­ment time. A corol­lary bene­fit is the huge reduc­tion is CPU load on the serv­ers since they are no longer per­form­ing cryptography.

My eph­em­eral know­ledge was to go and look up how to con­fig­ure it, and to research the exact bene­fits we could gain (which was a lot).

Application to CCIE and Cisco Certification studies

When I was study­ing for my CCIE, I made a point of one hour of READING time for every hour of LAB time. Without any doubt, this got me through my lab exam because I was able to take my per­man­ent know­ledge and solve an eph­em­eral prob­lem. On one of my lab exam days, I had to redis­trib­ute iBGP into RIPv1 which I hadn’t done this before, but I was able to work it out because I under­stood redis­tri­bu­tion and class­ful net­work­ing (not because I knew about RIP and BGP). Then I knew where to look up the rel­ev­ant mater­ial in the exam.

When I study for Cisco Exams, I have to remem­ber or mem­or­ise a lot of eph­em­eral know­ledge. Items such as con­fig­ur­ing fail­over for a Firewall, or an IOS inter­face to enable rout­ing. Mostly these ques­tions are to silence crit­ics who say that Cisco writ­ten exams are not prac­tical enough, but they are often phrased in such a way to determ­ine if you have absorbed some core know­ledge. Thus, ques­tions to con­fig­ure IETF encap­su­la­tion on a frame relay net­work can be phrased to prove that you know what IETF encap­su­la­tion is.

So fine, I have to know that, but don’t expect me to remem­ber the CLI within two weeks of the exam. But I will make a point of study­ing the under­ly­ing facts because I will most likely use those in real life.

Now I under­stand what they mean when they say — “study for the exam, not the real world”.

Postscript — The Silent Roaring in My Mind

After a long day when I am work­ing on new con­cepts and themes, or a long hack­ing ses­sion , I often get a roar­ing noise in my mind, some­thing like stick­ing your head out of the win­dows of a speed­ing car and you get the roar­ing noise in ears. Probably because of the rel­at­ive silence when I stop.

But its a weird feel­ing any­way. Some people get that feel­ing by listen­ing to cer­tain music, or exer­cising, but me — I’m a geek, I get it by learn­ing something.

(1) The name var­ies depend­ing on whom I am work­ing for, but the work remains the same. “A rose by any other name would smell as sweet” — Shakespeare

(2) For an example, look at the IBM Red Books. This is a reflec­tion of their ded­ic­a­tion to qual­ity documentation.

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