CWNP’s Intro video to 802.11ac
I was catching up on some of my subscribed YouTube channels this weekend when I checked in on the CWNP TV channel, I then found a new video that was posted by Tom Carpenter just last week. It’s a good 45 minute video that goes over some great fundamental details of the new 802.11ac standard.
It’s definitely worth a listen to if you have not done any other research on 802.11ac and you are curious at how 802.11ac is able achieve its new record of wireless speeds. It also explains that we will see 2 different waves of 802.11ac, wave 1 (going on now) and a wave 2 where will see even more improvements.
Now, I don’t want to ruin anything from the video but you can find the video here.
Blogging for 3 years now!
Another year down!
Time flies when you are having fun right! Last year my blog was seeing around 3600+ visits a month, now I am seeing stats from 5,300 views to 7,400 views a months! A large jump from previous years, nowadays I get as many views in a month as I did for my whole first year of blogging! It just goes to show you what is possible when you put your mind to something and stay dedicated to a cause (or your career in this case). I can only image the statistics I will being next year, just thinking about it motivates me to write more!
Top 5 articles for the year: (Still a majority of these posts are wireless related!)
- Understanding a Wi-Fi connection with 7,224 views (10,442 All-time views)
- Wireless networking and the 5 Ghz RF range with 2,751 views (4,878 All-time views)
- Packet Flow through a Cisco ASA with 2,331 views (2,970 All-time views)
- Cisco WLC Interfaces with 2,174 (4,242 All-time views)
- Let’s look at 802.11 beacon frames with 1,881 view (3,838 All-time views)
Total visits to the blog to date: 111,071!!!!! (Over double of last year’s stats!)
Why spectrum analyzers are still relevant.
Wireless networks have seen many different trends emerging over the years, probably one of the most prevalent trend is the ability for access points to monitor to the RF spectrum around the access point. Whether you work with Cisco CleanAir, Aerohive, Aruba, or one of the other big wireless vendors they each have their own way of monitoring and reporting the surrounding RF environment. This is definitely a feature that is very useful for viewing the overall health of the wireless spectrum, after all this spectrum is the layer 1 medium for the WLAN and if there is a lot of contention/interference over the RF then the WLAN will see a performance degradation.
One thing I have inadvertently seen this built-in feature do is provide a false sense of security and make people believe they do not have a need to have any other spectrum analysis tool. There is one flaw with relying on this feature, it is the fact that this feature will only provide you a view of the RF surrounding the access point, while your first reaction is going to “well yes it does, that is what it is supposed to do” this feature does not (and will not) provide you with a view of the spectrum from the client’s perspective. Consider a deployment where you do not have access points peppered around an area every 20 feet and instead have access point spread out every 50-80 feet and you hear consistent complaints of wireless issues. The first reaction of any network engineer is going to be check the access point:
- Is the access point servicing clients
- Is there a configuration issue
- How does surrounding RF look
- What do the wireless statistics look like
Now usually one of those four things will point you in the right direction, but what I find that is pretty common trait is that after reviewing the RF statistics surrounding the access point (and assuming it looks good/normal) no further thought will be given to the layer 1 medium simply because they looked to access point. All the while the client wireless device might be a good 30 ft away behind a few obstacles surrounded by or near a set of interfering devices. That is where you would want someone on the ground with a spectrum analyzer.
I’m not saying you need to have a spectrum analyzer everywhere you have wireless because we all know in large networks wireless can grow drastically and certain large networks can see thousands of access points across many different offices, but I merely want to point out a flaw in completely relying on a technology that provides RF Spectrum visibility from the access points perspective, because that is all it is.
CWNA Check!
Well, I finally got around to taking a shot at the CWNA exam and ended up with some successful results! It feels like an eternity but over 2 years ago I took a stab at CWNP’s CWTS exam. If you remember from my assessment of the CWTS exam itself I was able to knock it out fairly easy with a passing score in the 90’s with an ending statement that I should have just skipped the CWTS and went straight for the CWNA. Well after passing the CWNA with a score again in the mid-90’s I still stand by that statement. However I’m sure the additional 2 years of experience since then provided me with a considerable handicap.
In regards to my study preparation for the CWNA, just like I did for the CWTS I used official CWNP CWNA Study Guide from Sybex, that and the 6 years of wireless experience I have. Just like the CWTS exam I found the CWNA to be very straight forward it did have a lot of good questions that made me do a bit thinking and the questions were much more detailed then what I remember dealing with on the CWTS exam. This time however a quick read the through the CWNA study guide was pretty much all I did. I did utilize one or two of the question pools that are available for purchase on CWNP’s website and the questions are great for exam preparation if there is anything I commend CWNP for it is for providing great study material for thier exams.
Now, I still consider the CWNA should be basic knowledge for any network administrator/engineer that has to work with an extensive WLAN. After all everyone knows wireless is a bit more complicated then just deploy access point and hope for the best, having an understanding of the 802.11 technologies is detrimental to a successful WLAN deployment in my own opinion. Now while CWNA doesn’t cover all the 802.11 protocols in great detail I think it is a great entry point at understanding the technologies from a high level. Now, i just hope the CWNP certification gain a bit more traction in the job and because just as well as the CCNA/CCNP certification.
Reconsidering the way we think about ‘virtualization’
Ever so often I will see an article that discusses ‘how few people know about virtualization’ or ‘how many people do not run virtualized environments’ and I do have to admit a part of me shakes my head at these articles. Mainly because those articles (in my mind) do not properly describe the ‘virtualization’ they are trying to talk about. They simply mention the term ‘virtualization’ and continue on when the real fact of the matter is I’m sure 99% of us in the IT world are dealing with virtualization right and don’t even realize it.
Whenever people discuss virtualization it is typically going to involve VMWare, Hyper-V, or Citrix, however when you consider what virtualization really is, it has been around decades going back to Partitions on an AS400 midrange system. I’ve spent a fair amount of time thinking of a way summarize ‘virtualization’ and I think this one might have been one of the best
“Providing multiple services securely and isolated over the same physical hardware”
(There is probably a flaw in that statement but anyway) Now if we think about that for a minute and then think about network designs (Yes, I had to bring up network design, you knew this was going somewhere network related right?!) we virtualize our networks to an extent:
- VLANs Virtual LAN – Providing multiple Local Area Networks over the same physical switch
- VRF Virtual Routing Forwarding – Providing multiple routing instances within the same physical router. A layer 3 VLAN if you will.
- VDC Virtual Device Context – Similar to VRF’s but for Nexus/Data Centers.
We even have virtual Wireless LAN Controllers, Virtual Firewalls, Virtual switches, and so forth
Now when you consider VLANs, VRF, & VDCs a virtualization technology I think almost everyone will attest to being a familiar with virtualization in one aspect or another. So I think it is time we stopped considering virtualization something new and something that is limited to ‘servers’ as it has really been with us for a while, we’ve just been abbreviating for years!
(That and the fact VMWare/Hyper-V have been out there for years now)
Network Management a forgotten art?
I’ve worked with many different network engineering departments at many different companies and I must say one of the biggest trends I typically see is the fact management capabilities are typically always lacking, and usually it is due to one of the following reasons:
1. A complete lack of management tools, while this is usually the rarest issue out there, there are some places that don’t even rely or have any type of network management tools and you see some type of excel spread sheet or network share containing copies of device configurations. Now there is nothing wrong with this especially if you are a real small environment however it is definitely not ideal for larger environments and should be avoided.
2. Outdated network management tools, this is only somewhat better then not having any type of management tools. That is relying on tools that have been EoL for years, to the point you either need to maintain the network management application or worry about it failing. As with any type of network device the network management software needs to evolve with the network, as more and more technologies are rolled out to the network you need to ensure the management of those technologies scale just as well.
3. Too many network management applications, while you wouldn’t think this is a bad thing. It can be very easy to get carried away with network management. For example look at Cisco, they practically have a flavor of ‘Prime’ for everything CX-Modules, Wireless networks, wired networks, Voice/Video, which in itself can get overwhelming because usually on top of those platforms are additional platforms for configuration or performance management (whether it be SolarWinds, PRTG, WhatsUpGold) and your management turns out to be very de-centralized sometimes leading to confusion in itself and in some cases causing companies to purchase duplicate licensing that they don’t need.
4. Not knowing what to actually monitor. Granted efficient management techniques come over time and experience. to be honest typically the first time many people setup any type of NMS they are instantly ‘wowed’ at the sheer amount of information they get by default (typically historical performance information, NetFlow stats, configuration management) that they do not realize what they don’t see until they find themselves in a troubleshooting situation or outage and begin wishing they had just a little bit more information. For example look at SolarWinds NPM only recently did it start adding support to viewing routing tables and see routing neighbors, in the past custom pollers would have to be setup to see this type of information. However you still need to rely on custom pollers to pull specific MIBs for FHRP status, which in my mind is just as important as monitoring a routing protocol.
Now, we do have a very large arsenal of tools to choose from when designing our network management environment and it can be intimidating at first, but the important thing is to understand what we ‘should look at’ depending on the situation we are attempting to troubleshoot. A few great tools are:
Historical performance records are always great, since those type of tools will passively (and automatically) establish a baseline for us allowing us to quickly determine if a network device or segment is experiencing any abnormal performance.
Syslog/traps, remember syslogs and traps are basically the equivalent of error logs in the Windows event viewer and are able to quickly tells us if the router is experiencing any type of issue. Of course logging needs to be properly configured and possibly filtered to ensure the logs give us the information we need to see quickly without having to filter thousands of events!
NetFlow data is an amazing resource especially when teamed up with NBAR these can quickly tells us what traffic types and patterns are going through our router, so let’s say a particular remote site is experiencing performance issues NetFlow and easily tell if we have some specific traffic over utilizing the bandwidth or flooding the interface.
Configuration management, while this one is a given for any large network it can also be used to quickly identify any network changes that could be causing any negative impact, and pretty much all of the configuration management tools out there today include the ability to automatically compare previous configuration sets highlighting the differences.
Software management, you might not consider this one at first, but knowing what type and version of software is running in your network is a very important aspect to be aware of, especially if you are unlucky enough to stumble upon and a bug within the software. In those events you want to be able to quickly identify what other devices in your network will be affected by this software bug and you will also in turn want a simple and manageable way to upgrade and replace that software.
CCIE or Null! 