Computers and Technology Inside

Obviously you know you have a problem when the support desk phones start ringing, or link monitor statistics begin to display wildly errant values such as high latency or SNR. But what or who is the culprit? The wireless troubleshooting techniques described here should only be followed once you have ruled out problems at the tower side such as flakey cabling, flapping switch or router ports, routing issues, false positives (ie. an unusual, but normal increase in user traffic), or unscheduled upstream or backhaul provider outages.

Following a logical troubleshooting procedure limits the downtime needed to test a wireless issue and will help you arrive at the solution sooner. So first, think about and note the following. By answering the questions below, you will find one area remains for which to focus your attention. And as I always stress, if you feel overwhelmed, do not feel shy calling your favorite IT consulting firm for help.

SCALE

Is the problem affecting the whole network, or a specific tower, sector or link? Or maybe a small group of customers in a single area are affected?

INTERNAL FACTORS

Are you aware of any recent configuration or equipment changes made to the affected portion of the network? If so, what are they?

EXTERNAL FACTORS

What’s going on in the environment? What is the adjacent competition doing, if anything? Are you aware of any new construction that could be presenting a new obstacle within the coverage area or link experiencing the issue?

TIMING

Is there a certain time that the problem occurs or started to occur? Is there a pattern to its occurrence or is it more random in nature?

1. Baseline analysis: check RSS, SNR, scan, latency and performance baseline data (log files, MRTG, Solarwinds, etc.). Note the average value for each, as well as the dates and times any dramatic changes in these values occurred.
2. Changes: check with colleagues to determine if any changes in equipment and/or configuration have occurred since the times noted in step #1 above.
3. Customer feedback (placed at step 3, but you may want to move it further down on the list, depending on your situation): If you’re a WISP operator, you are already fully aware of how slippery the slope can get when gaining customers’ perspectives. However this should not be overlooked, especially if the problem is affecting multiple customers. Correlating affected customers’ stories can quickly eliminate false information while solidifying the facts. Particular attention should be given to asking customers questions regarding the use of wireless equipment within their own home and immediate vicinity.
4. Check radio configuration: access the affected radio(s) using the connection method with which you are familiar (telnet, HTTP). Check the obvious areas such as firmware version, power level, frequency, IP configuration (address, gateway, DNS, SNMP, SNTP, etc.), modulation schemes (if applicable), SSIDs, authentication (static, RADIUS, TACACS, keys), encryption, QoS, VLANs, etc.
5. Check radio operation and monitoring tools’ data: link activity (TCP/IP stats such as Rx and Tx packets), errors (discarded and retransmitted packets), conduct wireless performance and ping tests and collect current RSS and SNR readings; compare these to the baseline in step 1.
6. Spectrum scanning: requires taking the production system offline for the time it takes to perform the scans. Using the radio’s built-in spectrum analyzer is the most practical and unobtrusive means of sampling what’s going on in the RF environment. If the radio does not include a spectrum analyzer but the installation consists of a RF cable run into an enclosure or customer premises, a stand-alone spectrum analyzer (Anritsu, HP) can usually be attached to the antenna with the correct adapters (be sure to compensate for any loss added to the path between the radio and antenna). The benefit of using a stand-alone spectrum analyzer is its flexibility and ‘real-time’ viewing aspect.
7. Hardware: inspect all connections for corrosion, water ingress, tearing, bending, cracking, etc. If suspect components are found, begin swapping out the easiest pieces (RF jumpers, connectors, filters, lightning arrestors, PoEs), retesting as per step 5 and 6 above after each change. Last to try swapping is the radio itself; verify the correct configuration and firmware is loaded on the swap unit prior to the exchange.
8. Parallel system testing: at this point there are only a couple of components that remain to be tested; the tower or customer RF cable (LDF4-50, LMR400) and antenna. Since these items are not easily swappable, parallel system testing makes sense. It is best to conduct this testing using the same equipment as is installed in the production system. However, many operators and field services make use of a pre-configured ‘test rig’ that is relatively easy to deploy to save time. In this case, calculations should be done to compensate for the loss or gain in the path as a result of testing with dissimilar equipment before comparing to a baseline. Also, the active system’s radio(s) should be disabled during testing using the parallel system to prevent masking the results. If possible, it is highly recommended to perform tests in both vertical and horizontal polarities and at different elevations. If the parallel test system shows similar characteristics to the affected installed system, noise mitigation will be necessary. Make sure you have recorded all stats, scans and other test results so as to determine the course of action (ie. swapping out a faulty sector antenna) that will best reduce the effects of noise or interference as well as minimize downtime.

3D printing is very cool in my opinion. It has led to the manufacturing of a wide variety of products. These products have been very intricate in many situations, as the “design rules” of 3D printing are much easier to follow than in other forms of manufacturing such as machining or molding. The rules simply aren’t the same; this means that some seriously intricate designs and products can be brought to life. These designs can involve full functioning parts right out of the machine, interesting feats such as a ball within a ball, and organic shapes with curves and hollow sections. Some of the same designs used in 3D printing couldn’t even be pitched at other machine shops and manufacturing plants. These places would simply have to reject those orders; it’s impossible as the design rules aren’t the same.

Through machining, most methods involve a drill bit coming down on a block of material, or literally a saw of some kind cutting material. CNC cutting is the strongest attribute about machining in my opinion, so let’s compare 3D printing to that. CNC cutting uses a drill bit to come down upon a block of material. Typically, this block of material can turn, angle, and rotate to hit the drill bit at a certain spot. Unfortunately for this type of manufacturing technology, it is very difficult to replicate organic curves or shapes. This process is definitely not a layer by layer process, but a material removal one. The possibility of hollow spaces isn’t there; it’s simply impossible. For this reason, creating intricate models that offer organic curves, shapes, and hollow spaces are simply out of the question.

3D printing doesn’t have much competition from mold manufacturing as well. Well, that isn’t entirely true. Mold manufacturing is much less expensive to create mass quantities of products, but these products follow a different set of “design rules” and simply can’t create some of the same products that 3D printing can. Based on the fact that plastic will be shot inside of a mold, there isn’t an easy way to create hollow areas. The possibilities for organic shapes and curves is very doable, but the detail isn’t quite the same in many situations. Overall, 3D printing dominates the efforts of mold manufacturing on a small scale when it comes down to product vs product. When speaking in a large scale mass manufacturing situation, mold manufacturing will typically win the bout.

Various form of manufacturing serve their own purposes, but I believe product vs product, 3D printing poses one of the best options for creating organic, curved, hollowed, and detailed pieces. The possibilities within this technology are more than vast. If it can be drawn up on a computer, it can likely be 3D printed. That’s not to say that it won’t fall apart if you design a product with.01 mm of spacing, but with little knowledge of the “design rules” of 3D printing, odds are that you will do alright when it comes down to producing 3D printed parts.

There are many different parts that make up a website. If you have ever tried to create a website, then you already know that there is a lot of work that goes into it. It is essential that you take the time to make sure that your website has a great appearance because if it does not, then you will find that people will not want to visit your site. The main reason that people create websites is to let people know about the products and services that they can provide.

One of the main things that people use to get their website set up is flash. It is easy for people to use flash because it is extremely user friendly. You do not have to know everything about flash in order to use it on your site. This is why people choose to use this. There are many different aspects of creating a website that you can put together by using flash.

One of the many different features that you can use is the flash flip book. You will be able to put up a lot of different pictures and images on your site if you decide to use this feature. There are many benefits that go along with using this feature. Of course, since this is flash, it is easy to incorporate into your website. You will not have to worry about having any issues with using this.

The flash flip book is totally customizable, and this is something that people like about it. You will be able to incorporate any images that you would like to have on your website. If you have any problems with using flash, you will be able to call their customer support in order to have your issues resolved. This is extremely important because there are many people that like to set up their own websites, but they do not know exactly how to go about doing it. This is when it is nice to have the ability to be able to call for assistance.

You will be able to figure out how to use the flash flip book to provide your website with a unique appearance. This is because there are many different aspects of this product that you will be able to customize. You will be able to use your imagination and make your website have the appearance that you would like it to.