I now need to do the remaining labs in the lab portfolio. There are especially some case studies that bridge all the knowledge together (or so it looks like, we’ll see). I do know however, that wireless is a huge area in and by itself.

I will think of some scenario to build up using the topics I have learned so far. But right now I really must get some sleep. Im smashed, and work is as always really demotivating me quite alot.

Plan is to get 2 hours reading done on friday, and noting down any things i need to study further, and then see how much time I require before the exam. Definitely getting closer.

Off to sleep, night!

I have a sneaking suspecion that I better pay alot of attention towards the wireless section of the BCMSN. It seems like its “out-of-scope” of the BCMSN, but Im quite confident that Cisco will really smack me on it for some reason. The whole gain/loss/radio frequency stuff is not a topic I have paid much attention to in the past, so its quite new for me.

I am convinced though, that studying it, will come in handy in real life. For example, at my current work, we have the Cisco wireless controllers along with some LWAP (Light Weight Access Points), and also some autonomous accesspoints (1242′s). All of it working like a charm. The controllers can actually take over from each other in case of failure. Also, on a side note, I saw some slide’s from the WCS module that can do real time tracking of wireless clients, quite cool

Again though, the lack of equipment is getting to me. I would really like to have some equipment to try everything out on. I have to live in the real world though, and that includes not being able to spend $5k on Cisco gear right now.

Right now im off to relax a bit before reading the last 40ish pages of the study guide tomorrow. I plan to have the study guide finished tomorrow along with the last CBT nuggets on wireless. I will also start on the wireless labs tomorrow. I hope to have the wireless topic nailed down on friday. At least thats my goal for the week.

Must schedule exam next!

Lately I have been in the need of the right equipment for quite a few labs.

What I really need is some equipment that is able to do both Dynamic Arp Inspection (DAI) and IP Source Guard (IPSG). The dynamic arp part is supported on 3550′s as far as I can see, but IPSG is not. It is only available on 4500′s and 6500′s, and I dont think playing on the core 4507R’s at work would be a wise choice

I think I will look into different solutions for rack rental. I saw somewhere that its about $15 for 5 hours lab time. Thats not bad at all. In fact its alot cheaper than I thought it would be.

I need to practice alot of commands for alot of topics, which is what im spending my time doing right now. When I come home I will hit the 2nd last chapter in the study guide. The last two chapters has been pretty useless for the BCMSN exam at least.

A seemingly large topic I need to study is the wireless section. I do have access to some controllers, but I cant really play around with them since they are in a working environment as well. At some point during this week, I will need to schedule the exam, so I have a goal to work towards.

Been reading the study guide about L2 security. You can really mess up a whole network very simply, and you can basically take down the whole thing pretty easily if your switches are not configured correctly. There was also alot of things about IP spoofing and ARP spoofing. Pretty nifty stuff, and you can all secure your network alot by making some pretty basic choices, and execute them all over your network.

A non-intrusive command like: “ip dhcp snooping”, executed in global mode, and then “ip dhcp snooping trust” on the interface pointing towards your DHCP server, will set you up for a pretty good baseline to configure your network security around. Both IP source guard and dynamic arp inspection use this table to make smart choices about “good” and “bad” traffic on your network.

I will be doing up some labs on it all tomorrow, to see how it actually pans out on the switches. And then its off for the weekend. Will probably only do a few hours reading this weekend, but then i should be well on my way to finishing the study guide.

On a side note, the cellular network i spoke of yesterday, is still not up and running fully. Must have been a big failure, but im sure TDC is working around the clock to make sure its comming back online.

So im studying redundancy features, especially gateway redundancy features. I think this is some impressing technology. Basically there are three versions, HSRP (cisco proprietary), VRRP (IEEE Standard) and GLBP (cisco proprietary). HSRP was introduced in 1994, and VRRP in 1999, GLBP is alot newer, introduced in 2005.

HSRP stands for Hot Standby Router Protocol, VRRP is Virtual Router Redundancy Protocol and finally GLBP is Gateway Load Balancing Protocol.

Given the incredible redundancy they each perform, they are incredible simple to setup. It works by creating a “virtual IP” address along with a “virtual MAC” address. (Mac will become: 0000.0c07.acXX where XX is the HSRP group number).

VRRP is basically the same, but is a standard, also as standard provides some faster timers ~ which will equal faster convergence.

GLBP is somewhat different though, in that it utilizes all links in some manner. an AVG (Active Virtual Gateway) is choosen to manage a bunch of MAC addresses. Each AVF (Active Virtual Forwarder) then gets a mac address. When an ARP request is received, the AVG hands out one of these MAC addresses defined by how you want the load balancing to take place. You can choose between host-dependent, round-robin and weighted, where you can rate each router/switch according to the traffic flow.

All in all, very cool stuff

Been reading about CEF yesterday. It doesnt take up much of the exam blueprint, nor CBT nuggets coverage of it. However, it seems that theres more to this than what meets the eye.

I also need to figure out what CEF is doing in routers. My assumption is that its being implemented in IOS and where support for hardware is available, it downloads the FIB and adjacency tables from the control plane to the data plane for fast switching. I doubt all routers have asic hardware, capable of CEF operations, and i know CEF is running on some of my IOS 3640 dynamips boxes.

Anyways, finally got another 2960 (I just found out this one was a G model (all gigabit ports)), so i can set up full scale labs (well, almost), consisting of 2 access-layer switches (my 2950′s), 2 distribution-layer switches (the 2960′s) and my dynamips box which is able to physicall hook up 2 3640′s with the NM 16sw module for L3. The 2960′s are pretty cool L2 switches, which ill be sorry to return after im done borrowing them from work. I now know for a fact, that if I had 95 friends, I would be able to hook them all up to my home rack

On another note, I just found out that Cisco charges $80 for a mounting-bracket pack (2 pieces of metal). Thats just insane. Ill order some noname ones, which will do the same job, but without the Cisco logo, but for $5 instead.

Today I have spent about 2,5 hours studying different features that enhances the switched network. This includes labbing up BPDU guard, Loop guard, UDLD Aggressive mode, BPDU filtering. Also I find the automatic error recovery feature very interesting.

You can set certain causes to put an interface into the errdisabled state. For example if you enable BPDU guard, and a BPDU is “heard” on the interface, it puts the interface into errdisabled. But you can set a timer to “wake” the interface back up again, so its not a permanently state that an administrator must take action to remedy, namely sh/no sh the interface.

Also, it would seem there is alot of different functionality in different switches, not only between CatOS and IOS switches, but also very much between different series (2950/3550/4500/6500).

And for some reason, since I cant test out the private-vlan feature on my lab (this is a 4500/6500 feature), it wont really stick in memory.

Inter-Vlan seems very cool, but a lack of a 3550 is really starting to show now. I am using a Dynamips box with the NM-16sw module for L3 switching, but the commands are different. So far I have done a few labs using SVI (Switch Virtual Interface) routing.

I am going to look around on the net for some memory enhancing techniques, as I seem to be forgetting stuff I have read and/or done in a lab.

On another note, I really need a consistent storage solution, but im a bit vary of shelling out the $1000 on a NAS with 3 TB (4, but in raid). Note to self, learn to make these decisions.

Now I am going to skim through some CBT, and then watch an episode of X-files to calm down