November 10th, 2009 -- Posted in Other |
Overview
The process of troubleshooting your network if it has wireless components is somewhat more complex than wired infrastructure. In fact you must troubleshoot both wired and wireless infrastructure to determine the problem. The methodology of starting with cabling from the client and working through the OSI model to the application layer is effective. The wireless client traffic doesn’t see any cabling until there has been association with the access point. In essence there is a data link between wireless client and access point. With that established there is data link traffic between access point and wired network switch.
The wired client has a Cat 5 cable plugged into the desktop that terminates at a wired switch. All clients associating at a specific access point now share a single Cat 5 cable run from access point to switch. That makes troubleshooting easier since cabling is a source of a lot of network problems, however any problems with that cable affects all clients. It is important to minimize the number of access point clients for maximum performance. Commercial network implementations average 10 – 24 clients per access point.
The key with troubleshooting is to determine what has changed. Sometimes it is hardware that isn’t working or some change made such as new software, configured equipment or additional employees stressing the network. It could be a specific issue or several problems. Start with the client adapter, determine the specific symptoms and go from there.
The following is a series of questions that can used as a guideline during the troubleshooting process:
1. Can the wireless client associate with any access point?
2. Can you ping the switch IP address?
3. Can you ping the router?
4. Can you ping the DHCP server?
5. Does the client obtain an IP address?
6. Is the WAN circuit available?
7. Has new software been installed on the client?
8. Do all clients experience the problem?
9. Is it random or a specific pattern?
10. Is it server specific or application specific?
11. Is the DNS server IP address setting correct?
12. Is there a firewall that is filtering traffic?
TOOLS:
a) Wireless client software shows status information such as access point association, DHCP enabled, IP address, default gateway, DNS server address.
b) Windows control panel shows wireless adapter settings, firewall configuration etc.
c) Ping will verify that network routing is working.
d) Network packet sniffers examine packet information such as protocols, filtered programs or errors with applications.
e) Spectrum analyzers detect frequency interference and possible sources.
COMMON WIRELESS PROBLEMS:
Wireless Client Settings
• Upgrade the manufacturer client adapter driver.
• Implement current Windows operating system service pack.
• Examine client data rate, transmit power, preamble, roaming decision, WPA settings.
• Confirm shared keys if implemented aren’t mismatched between client and AP.
• Examine IP address settings. DHCP will send specific settings to each client. Those clients without DHCP must configure IP address, subnet mask, default gateway and DNS server IP address.
• The client SSID name configured should match what is configured at the AP.
Access Point
• Confirm the APs have the recommended IOS version with the specific feature set.
• Examine AP mounting and modify if necessary using the installation instructions.
• Delete any configured loopback addresses.
• Configure transmit power setting and decrease when channel interference occurs.
• Mixed 802.11b/g environments must configure each AP with 802.11b basic data rates.
• Configure data rate and duplex settings to match between AP and switch.
Design
• Configure data rate and duplex setting to match between wireless bridges.
• Standard Cat 5 UTP cable should be a maximum of 328 feet between AP and switch.
• Distance from the wireless client to access point should not exceed the specified range.
• Maximum number of clients per access point should not exceed 17 – 24.
• Don’t assign channel overlap between neighbor APs.
• Configure spanning tree protocol at root bridges
• Configure non overlapping channels of 1, 6 and 11 at 802.11b and 802.11g APs.
• Don’t configure multiple root bridges on the same WLAN
• Implement the most current version of Windows Server, IAS RADIUS Server or Cisco ACS
• RF interference will occur in an unlicensed band. Minimize sources where possible.
Cisco Wireless Network Design Guide available at amazon.com and eBookmall.com
Shaun Hummel is an author of various technical books and has a web site focused on information technology job search solutions and certifications.
http://www.networkjobsolutions.com
Shaun Hummel, CCNP, is a Senior Network Engineer with 11 years experience in enterprise network planning, design, and implementation. He has worked for various private and public companies in Canada and the United States improving infrastructure, security, and management. He has written Network Planning and Design Guide, Cisco Wireless Network Design Guide and Network Assessment Guide.
www.networkjobsolutions.com
September 17th, 2009 -- Posted in Other |
Vinyl windows are very easy to clean and they are also a great way to get replacement windows without the high cost that usually comes with windows. There is quite a bit of significance when it comes to vinyl windows. It allows you to update your home rather fast and at a lower cost. This makes vinyl the prime way for you to replace windows in your home.
Other pros to vinyl windows
There are other pros to vinyl windows as well. You don’t have to deal with warped or rotting wood. You don’t have to deal with increased energy costs. There is no water or air damage that you need to worry about. You will find that there are many reasons why so many individuals are turning to vinyl windows as the way to weatherize their homes.
Another great pro to vinyl windows is the fact that they require very little maintenance. This means that they are easy to clean.
Cleaning vinyl windows
Something else that is great about vinyl windows is that you can install them and forget about them. The truth is that windows are, in many cases, the last thing thought about when it comes to a home. Although we look out through them everyday, we don’t think of how they need tender loving care. That is why vinyl is preferable.
What’s great is that you clean the interior and the exterior of the window like you would any other window. This means that you can stick with the frequency in which you usually clean your windows. As for the frame, it only takes water for you to clean it. It is as simple as that. It doesn’t have to be a huge operation and you don’t have to constantly be climbing on ladders to clean your vinyl windows.
To be more detailed, here is how you can clean vinyl windows:
- Raise the bottom sash so that you can tilt it toward you and make it flat.
- Use dish soap and water with a soft cloth.
- Move the cloth around in a circular motion until all dirt is removed.
- If there are spots, you can use 1 tsp. of Murphy’s soap with one gallon of water. Again, use a soft cloth in a circular motion until the dirt is gone.
- If there is any mold or mildew, use 30% vinegary and 70% water. This also prevents mold and mildew from growing back.
- You then repeat these steps for the top sash.
This is something that you will need to do with all of your vinyl windows.
Replacement
When you find that the color is not right or it is simply time to replace your vinyl windows, replacement is very easy. Because the installation only takes two people and you can just pop them in and out, you can have a different look to your home as frequently as you wish. It really depends on your budget. Fortunately, however, vinyl is tough enough during the installation process that you don’t have to worry about the vinyl breaking.
After you have replaced your windows, you’ll be able to go about your usual vinyl window cleaning habits. Just be sure to keep them very clean so that they will continue to look great on your home. This also makes them last even longer because they are not being eaten away by the mold, mildew, and dirt that tends to attack windows. When you see how much money vinyl windows will save you, you’ll be very glad that you made this decision and you’ll probably never go back to non-vinyl windows ever again.
September 16th, 2009 -- Posted in Other |
If you are building your own home, you can save quite a bit of money by ordering your vinyl windows for yourself and then having your carpenters install the windows. Ordering windows online can save you quite a bit of money. The windows will be delivered to the job site, just as they would if you ordered them at the store. But you will have saved, in some cases, thousands of dollars.
You have several different styles from which to choose when it comes to choosing vinyl windows. These include casements that crank out, double hung windows that slide up and out for easy cleaning and even sliding glass windows. These companies also make stationary “picture” windows in a variety of different designs. Picture windows do not open and are purely for appearances. They must be cleaned from the outside, but make tremendous difference in the curb appeal of your home.
The type of glass that you choose will play a big factor in price. Glass styles range from standard, insulated glass to glass that actually has a shaded look from the outside of the home. Most Vinyl Windows today are more energy efficient than the windows of the past because of the insulated glass. If you ever lived in an older home with windows that had storm windows and screens that had to put in the windows all of the time, as well as being constantly painted, you will marvel at the ease in the maintenance of vinyl windows.
In addition to windows, Lange, Crystal, Simonton and Hurd also make patio doors in a variety of different styles that are also vinyl. These sliding glass doors are a vast improvement over the older doors that had tracks that always seemed to collect debris. Best of all, they are well insulated; come in a variety of different styles, including the “French Door” look, and require no maintenance.
Which would you rather be doing on a warm spring day? Lighting up the barbeque grill or painting your wood windows to keep them looking nice? Chances are, if you are like most people, you will choose the former option. Again, the only thing you need to do with vinyl windows is wipe them down every so often and clean the glass. They are easy to maintain, are very attractive and come in every style imaginable. There is really no reason to choose any other types of windows for your home than Vinyl Windows
