As many of you have noticed, I’ve ramped up my review with beefy notes in nice pastel colors – my lame attempt to attract the ladies. Other than my wife, who reads looks at this blog once in a blue moon, all my readers have been mostly males. That’s all good. I’m sure you all enjoy the cool-in-the-eyes theme I’m trying to emulate. I was told ladies like pastel.

At this juncture, I’ve been studying BSCI for about 3.5 months now. I can honestly say that I have learned a ton already. Not mastered anything yet, though. But I expect that will come. It’s exciting to be at this stage because there is just so much to learn. I feel like a huge tree of knowlege just sprang up in front of me and I’m free to pick the fruits it bears. I just have to be careful though. There’s a saying: keep your friends close, but keep your enemies closer. I don’t really have a point to that. It just entered my mind as soon as I typed “saying”. But there’s another expression that comes up often, specially to those who achieve a higher degree of learning: “The more you know, the more you learn you don’t know”. Something to that effect. What I’m discovering as I gain deeper knowledge of routing protocols, metric calculations, etc., I find myself asking more and wanting to know more. When I began studies for this track, I decided I would stick with just the intermediate-level texts and materials to keep me on track of a scheduled and calculated study pace. Back in July, I pictured myself to be taking the BSCI exam by the end of this month. No way that’s going to happen. By the looks and feel of things, I’ll be happy if I can take it before the end of December.

Many CCNP candidates feel that the BSCI is the beast of all the 4 tracks. And I can see why that is. That’s also why I realized that sticking with the intermediate-level books can only hurt me. It is during this time that my curiosity about everything new that I’m learning is at it’s highest. My mind is always asking why and how whenever I learn something new. The books I’m using do not always satisfy. So I needed to consume more stuff of good quality. I picked up Jeff Doyle’s Routing TCP/IP, volumes I and II to fill that void. I had to, otherwise I would end up satisfying my hunger with crap. Allow me to analogize : Whenever I get hungry at work, I try to avoid going to the vending machine and buying all the unhealthy stuff they put in there. When I have them, I try to munch on some healthy nuts: cashews are my preferred ones. Sure they’re high in calories, but they are also proven to be high in fiber, omega-3s, and unsaturated fat (good fat). Not only that, they are filling and they suppress hunger so you don’t overeat later. So if given the choice to satisfy my hunger, twinkies or the healthy sfuff? They both satisfy your hunger but the effects are different.

I felt it was kind of the same with my learning. While learning all these new stuff is keeping me hungry, I need to satisfy that hunger with quality foods, before twinky-knowledge gets in first and I no longer want or am too full to consume the good ones.

A simple example: my BSCI book taught me that in order for a non-backbone OSPF area traffic to reach another area, it must be attached to a backbone area. That is area 0. I wondered why. So I googled it. Google said that if I don’t do that (attach a non-backbone area to the backbone area) other areas will be unreachable. Knowing that fact might be enough to get a correct answer on the BSCI exam. But then, reading some of Jeff Doyle’s teachings, he offers a more satisfying explanation: One of the positive arguments for OSPF – as a link state protocol – is that it has complete map of the entire network. This helps prevent routing loops, as opposed to a distance vector protocol where a routers knowledge of the network depends on what the next-hop router knows, which makes routing-loops more likely without careful administrative oversight. Another advantage with OSPF is the ability to segment a network into separate “areas” when it starts to get too big. That is good for easing some stress on the SPF calculations on the routers. As a result of the segmentation, routers in the same area get the over-all map of the network in that one area only. But don’t fret my bebes, OSPF has a mechanism in which information from one area is passed on to another area. An area will have a special router type that collects information for one area, and another separate database for information from another area. People like us call it ABR. The ABR connects two OSPF areas and maintains separate databases for each of those areas. It then passes along a summarized (and sometimes not) view of one area to another and versa vice. Essentially, each areas rely on the ABR to tell them what it knows about the other area. This is where the concept of link-state routers having the over-all map of the network sort of breaks down. In essence, this whole design of areas needing to find out information from it’s next-hop router, the ABR, about the network on the other side is a distance vector principle. And because distance-vector is prone to routing loops,  a loop-free inter-area topology can be assured by forcing all areas to only attach to one other area – essentially forming a hub-and-spoke topology between non-backbone areas and the backbone area. We  just like to call it area 0. For your FYI you can find this explanation in his article in networkworld. Or better yet, for a beefier explanaion,  it’s somewhere around page 382 of Routing TCP/IP, Volume I, Second Edition. You’d probably want to read from the beginning of that section to get the complete picture.

Anyway, where am I at in my studies? Well, I’ve nearly completed my first phase, minus IPv6. To be honest though, I almost don’t follow the different phases I set out to follow in the beginning. FYI, first phase was read all sections all the way through; second phase was re-read and write detailed notes; third phase was review – with emphasis on getting ready for exam. Right now, the first and second phases are completely intertwined and I’m hoping to start test preparation by November. I’m finishing up my notes on OSPF, with intentions to go back and hammer it in – because there’s just so much to know. I finished reading BGP but the write up will probably be equally massive if not more. First phase on multicast is also done. But I’m in the middle of re-reading and adding external readings on it.

There’s just so much to go through, I don’t know if I can get it done by December. We shall see, my friends. We’ll just have to see.