sâmbătă, 30 noiembrie 2013

Cisco CCNP Certification / BCMSN Exam Tutorial: Writing QoS Coverage - Computers

QoS - High quality of Service - is a huge subject on each the BCMSN exam and real-world networks. QoS is so large right this moment that Cisco's created separate specialist certifications that cowl nothing but QoS! It may be an awesome matter at first, however grasp the basics and also you're in your method to examination and job success.

If you happen to work with QoS at any stage - and sooner or later, you will - you've got to know learn how to write and apply QoS policies.

Creating and applying such a coverage is a three-step process.

1. Create a QoS class to determine the site visitors that will likely be affected by the policy.

2. Create a QoS policy containing the actions to be taken by visitors recognized by the class.

3. Apply the coverage to the suitable interfaces.

If the phrase "identify the visitors" appears like it's time to write an entry-record, you're proper! Writing an ACL is one of ways to classify site visitors, and is the extra frequent of the two. Earlier than we get to the much less-frequent method, let's take a look at tips on how to use an ACL to classify traffic.

You need to use both an ordinary or extended ACL with QoS policies. The ACL will be written separately, and then called from the class map.

SW1(config)access-record one zero five permit tcp any any eq eighty

SW1(config)class-map WEBTRAFFIC

SW1(config-cmap)match entry-group 105

Now that we have recognized the traffic to be affected by the coverage, we better get round to writing the coverage! QoS policies are configured with the coverage-map command, and each clause of the policy will include an action to be taken to site visitors matching that clause.

SW1(config)policy-map LIMIT_WEBTRAFFIC_BANDWIDTH

SW1(config-pmap)class WEBTRAFFIC

SW1(config-pmap-c)police 5000000 exceed-motion drop

SW1(config-pmap-c)exit

This can be a simple coverage, but it illustrates the logic of QoS policies. The policy map LIMIT_WEBTRAFFIC_BANDWIDTH calls the map-class WEBTRAFFIC. We already know that every one WWW visitors will match that map class, so any WWW site visitors that exceeds the stated bandwidth limitation will be dropped.

Lastly, apply the coverage to the appropriate interface.

SW1(config-if)service-coverage LIMIT_WEBTRAFFIC_BANDWIDTH in

Getting your CCNP is an effective way to spice up your profession, and learning QoS is an incredible addition to your talent set. Like I stated, study the basics, don't get overwhelmed by looking at QoS as a complete, and you're on your approach to success!

To move the BCMSN examination and earn your CCNP, you've got to know HSRP inside and outside! Part of that's figuring out how the MAC tackle of the virtual router is derived, and one other part is understanding find out how to change this address. We'll take a look at both options in this tutorial.

We've got two routers on a section working HSRP, so first we have to discover out what the MAC tackle of the HSRP digital router is. The show command for HSRP is present standby, and it's the primary command you must run whereas configuring and troubleshooting HSRP. Let's run it on both routers and evaluate results.

R2show standby

Ethernet0 - Group 5

Native state is Standby, precedence a hundred

Hellotime three sec, holdtime 10 sec

Next hiya despatched in 0.776

Digital IP deal with is 172.12.23.10 configured

Energetic router is 172.12.23.3, priority a hundred expires in 9.568

Standby router is native

1 state modifications, final state change 00:00:22

R3show standby

Ethernet0 - Group 5

Local state is Active, priority one hundred

Hellotime three sec, holdtime 10 sec

Subsequent hey despatched in 2.592

Virtual IP tackle is 172.12.23.10 configured

Lively router is native

Standby router is 172.12.23.2 expires in 8.020

Virtual mac tackle is 0000.0c07.ac05

2 state adjustments, final state change 00:02:08

R3 is in Lively state, while R2 is in Standby. The hosts are utilizing the 172.12.123.10 tackle as their gateway, but R3 is actually dealing with the workload. R2 will take over if R3 becomes unavailable.

An IP deal with was statically assigned to the digital router, but not a MAC address. Nonetheless, there's a MAC handle underneath the show standby output on R3, the lively router. How did the HSRP course of arrive at a MAC of 00-00-0c-07-ac-05?

Well, most of the work is already achieved before the configuration is even begun. The MAC deal with 00-00-0c-07-ac-xx is reserved for HSRP, and xx is the group number in hexadecimal. That is a very good talent to have for the examination, so ensure you're comfy with hex conversions. The group quantity is 5, which is expressed as 05 with a -bit hex character. If the group quantity had been 17, we'd see 11 at the end of the MAC handle - one unit of sixteen, one unit of 1.

On rare occasions, you could have to alter the MAC tackle assigned to the digital router. This is performed with the standby mac-address command. Just be sure to're not duplicating a MAC tackle that is already in your community!

R2(config-if)standby 5 mac-deal with 0000.1111.2222

1d12h: %STANDBY-6-STATECHANGE: Ethernet0 Group 5 state Energetic -> Study

R2show standby

Ethernet0 - Group 5

Local state is Lively, priority a hundred and fifty, might preempt

Hellotime four sec, holdtime 12 sec

Subsequent hi there despatched in 3.476

Virtual IP deal with is 172.12.23.10 configured

Lively router is local

Standby router is 172.12.23.three expires in 10.204

Digital mac address is 0000.1111.2222 configured

four state adjustments, last state change 00:00:00

1d12h: %STANDBY-6-STATECHANGE: Ethernet0 Group 5 state Listen -> Energetic

The MAC deal with will take a number of seconds to vary, and the HSRP routers will go into Be taught state for that time period.

An actual-world HSRP troubleshooting be aware: In the event you see fixed state modifications together with your HSRP configuration, do what you should at all times do when troubleshooting - test the bodily layer first. Best of luck on your BCMSN exam!

You may read more in my website , i'm completely satisfied that you just read my article, thnak you , you'll be able to go to right here sheraton miami airport



access point vs router

Cisco, HP, Aruba See WLAN Revenues Jump in Q2: Analysts - Technology - Information Technology

The continued growth in sales of smartphones and tablets--and their increasing use in businesses--is fueling the rapid expansion of the wireless LAN market, according to several reports released in recent days.In the most recent report released Sept. 6, Canalys analysts said the WLAN space--which includes access points and controllers--grew to $575 million in revenue in the second quarter, with 1.6 million units shipped. The revenue represented a 35 percent increase over the same period last year, when the market was worth $561 million, according to Canalys. The rising demand for better WLAN environments is benefiting market leader Cisco Systems, according to various analyst firms, but also helping growing rivals, such as Aruba Networks, Hewlett-Packard and Motorola Solutions, all of which saw their second-quarter revenue jump.The pervasive demand for WiFi connectivity--driven by the proliferation of mobile devices like smartphones and tablets--was the key reason for the g rowth, and enterprises will continue to see such technology push its way into the corporate world, according to Canalys analyst Alex Smith. Building WLAN environments that can handle the explosive growth of consumer mobile devices in the workplace is a key consideration for businesses going forward."Without a suitable wireless LAN strategy, a business will soon find its existing networking deployments overwhelmed," Smith said in a statement. "There is a lot of hype around the cloud, but the first step in taking advantage of shared resources is ensuring that the maximum number of users and devices can access them."Canalys analysts said that tablet shipments worldwide will grow from 45 million units in 2011 to more than 113 million in 2015, with smartphone shipments jumping from 455 million units this year to 864 million in four years.Also driving the healthy growth in the WLAN market was the migration to the 802.11n standard, which Canalys said supports a higher density of de vices and is fueling a strong refresh cycle in existing WLAN environments.Added: Canalys' numbers echo those from research firms Dell'Oro Group and IDC, both of which recently said that enterprises dealing with the influx of consumer mobile devices into their environments are driving the growth in the WLAN market.IDC analysts Sept. 1 said that in the second quarter, WLAN revenue grew 29.7 percent over the same period in 2010, jumping to $1.52 billion, with the enterprise WLAN segment growing 43.4 percent to almost $725 million in that interval."Enterprise mobility has emerged as one of the key priorities for CIOs and IT managers across all geographies, and the growth of WLAN market revenue during the second quarter is a clear testament to that market dynamic," Rohit Mehra, director of IDC's Enterprise Communications Infrastructure unit, said in a statement. "The tremendous momentum behind smart mobile devices and their continued uptake in the enterprise for business and vert ical-specific applications are driving enterprises to move forward with upgrades and extensions of their wireless networks."Dell'Oro reported Aug. 30 that WLAN revenue in the second quarter grew 24 percent, with enterprise WLAN revenue increasing 40 percent. All three segments--enterprise, service providers, and small and home offices (SOHO)--saw double-digit growth over the second quarter of 2010, the firm said. "Large wins drove exceptional sequential quarters for some vendors, including Motorola Solutions, up over 100 [percent] and Alcatel-Lucent, up over 80 [percent]," Chris DePuy, an analyst covering wireless LAN research at Dell'Oro Group. "This is an indication of how important WLAN is becoming to enterprises and service providers--that a handful of wins can register in the tens of millions of dollars for any single customer in any given quarter."Dell'Oro analysts also talked about the Bring Your Own Device (BYOD) trend, in which workers are bringing their own devices --such as smartphones and tablets--into the enterprise and expecting to gain access to the corporate network. It's the BYOD trend and the skyrocketing popularity of Apple's iPad that is generating a lot of revenue growth for WLAN vendors. The same can be seen in the SOHO segment, which is helping out such vendors as Netgear, Cisco and D-Link, Dell'Oro said.Regarding enterprise WLAN vendors, IDC said that Cisco's revenue grew 36.2 percent in the quarter, but that its market share dropped to just over 50 percent. Other vendors, including Aruba, HP and Motorola Solutions, also saw strong revenue growth, ranging from 52.7 percent to 65.8 percent.Canalys had similar numbers, listing Meru Networks as the fifth-largest WLAN vendor. Cisco remained on top, the firm said, with its market share increasing slightly from 53.4 percent in the second quarter of 2010 to 53.7 percent this year. Aruba had 14.6 percent of the market, with HP--leveraging its acquisitions of 3Com and Colubris Net works--grabbing 7.8 percent market share."As consumers boost both public cloud investment and mobile device adoption in the enterprise, the real winners will be wireless LAN vendors capable of steering government and business organizations to the right networking environments," Canalys' Smith said. "Before there was the cloud, there were wireless LANs, and they are still hugely important today."How to connect 2 WAN, 1 LAN through a Cisco router/2011/08/18/how-to-connect-2-wan-1-lan-through-a-cisco-router/

Linda is one online marketing manager at router-switch.com. Router-switch.com, a recognized provider of new, refurbished, and used Cisco router, switch, IP Telephone, Security & Wireless devices. Their goal is to deliver maximum value, impress you with their service and earn your repeat business.



access point vs router

Routeur Wifi plus iPod Touch equal to iPhone? - Business - Sales

When my friends ask me what is the difference between the iPhone and iPod Touch? I always told them, only the calling function, and the rest are almost the same. In fact, there is another important characteristic between iTouch and iPhone - "3G". The iPhone can use a 3G SIM card to connect to the Internet almost anywhere, but the iTouch can not use the wifi connection. So here we would like to discuss how to transform the iPod Touch into a 3G router with 3G. WiFi router + iPod Touch almost equal to the iPhone The wireless router is a kind of mini-wireless router (3G router) that converts 3G to WiFi signal, it also works with a SIM card and battery powered. So if you take a mobile wifi hotspot on the go, you can connect to the internet anywhere. Some may say I have an iPhone, which also contains the function of personal hotspot. I can use it for my iPod Touc h. It is true that the iPhone with iOS 4.3 can provide mobile wireless hotspot. But compare with the wireless router business, it has two major weaknesses. The main difference between the iPhone and personal hotspot router 3g 1. Data Transfer Rate: Bands professional wireless router as Huawei, ZTE, Sierra 3G router contain many series that support different speeds, such as 3.6 Mbps, 7.2 Mbps and 21 Mbps, but as we tested, MacBook Pro iPhone4 hotspot is only 1.1 Mbps. 2. Hotspot staff of the iPhone only supports three connections on Wi-Fi network, the ZTE MF60 3G router supports eight users with 21 Mbps broadband. WiFi router + iPod Touch => iPhone (FaceTime on the go) In fact, if you have a wireless router in your pocket (100 - 200 USD), it will be cheaper than the iPhone contract almost anywhere, and can not only enable your iPod to have a connection forever, but you can make Skype calls and listen to music without having to worry about the usual limits of size iPhone, because you have Wi-Fi. You can also share the connection with a total of eight machines, including video calls with FaceTime wifi only. No configuration There is no need to configure fo r Modem sans fil, simply insert the SIM card and turn, then you will find the identity WiFi on your list of WiFi on the iPod Touch.Note: You can find the WiFi SSID (Service Set Identifier WiFi) and password by default inside the back panel of the router 3g.

/3g-router.html?utm_source=blog&utm_medium=janna&utm_campaign=3g+router



access point vs router

iPhone Tutorial - 5 Tips When Traveling Abroad With Your iPhone

I have recently started traveling around the world and have relied immensely on my iPhone to make the journey more enjoyable, prevent loss of information, and even point me in the right (or if I wish random but interesting) direction.I will briefly teach you my favorite 5 top tips for traveling abroad with your iPhoneIt is remarkable how much the world, as well as our daily lives have changed since the advent of mobile phones and in particular smart phones, such as the iPhone 3g by Apple. Some of us can remember the days when we use to make appointments once a day and kept them because there was no way to communicate the change of plan unless you were at home. Nowadays we need to be able to use the tools to our disposal to make better informed decisions... Even when on holiday or traveling.The fact that there are websites that cater solemnly for providing high quality iPhone tutorial videos and cheat sheets is testament to this new wave of technology.The cost of traveling with the internet in your pocketWith the recent advances, especially with the large amount of high quality Internet-connected applications that are available for the iPhone, trying to accomplish your daily tasks without the Internet on your phone becomes a problem.This is a dilemma myself and other high frequency or power users of the iPhone have faced when having to travel abroad with your iPhone, which brings a few interesting challenges with it when you find out the roaming rate for data is between 3 and 6 between Europe and the rest of the world.Luckily I have traveled internationally with my iPhone many times and found some novel solutions and will now supply a few tips to make traveling abroad with your iPhone a painless and more enjoyable experience.Tip 1: Disable voicemail before leavingMost carriers for the iPhone will charge you to receive voice-mails while you are abroad. With the Visual voicemail feature of the iPhone this means you will be charged international rates every time someone leaves a voicemail, whether you listen to it or not. It is easy to avoid these charged by disabling your voicemail while travelling abroad. For UK customers, to switch voicemail divert off dial 1760. On your return to switch it back on dial 1750.Another way of disabling voice-mail before traveling is to type #004# and call. Enabling voice-mail on your return can be done by typing *004# and pressing call. Not all Networks across the globe allow this functionality, so if this tip doesn't work for you just call your operator support to disable the visual voicemailTip 2: Disable data roaming.Unfortunately data roaming with the iPhone Internet enabled applications can work out costly if you weren't expecting it. It is surprising how much data an application such as email or normal web browsing can consume, which will leave you with a big shock when you find the bill at the end of the month.To do this from the home screen click settings- general settings- network- data roaming - offThere are ways to still use your applications such as GPS navigation even with this feature turned off as explained later in this tutorial.Before you go traveling I suggest you clear the data counter so that if you do switch on the data roaming occasionally for checking a important email or website, you will know exactly what the charge will be. To clear the data usage counters, from the home screen press the settings button, then press "usage" and lastly press "reset statistics" button.Tip 3: enable flight mode when not expecting calls.If you are on holiday, I'm sure you don't want to be interrupted while listening to your favourite mp3's while tanning on the white beaches of Sardinia or another gorgeous part of Europe.oThis will stop you from receiving calls while activated, but more importantly prevent your battery from running flat for when you really DO need to make an important call.o if you are near a WIFI access point you can still activat e the wireless While the phone is still in airplane mode giving you the best solution:Internet access without data roaming charges and linger battery life.Tip 4: Download the GoogleMaps so they are ready for GPS without incurring data rateso Download the google maps prior to leaving your home country. All you need to do is to open the google maps app, search for your destination( preferably your hotel accommodation or street address ) and zoom in and around.o The Google maps app will keep these maps in its temporary cache and will not require Internet access to display them again once you arrive in your destination.o Prior to leaving I suggest to drop a pin on your points of interest, which you can then use as place marks to find your way around.o If you have access to a Internet cafe or WIFI access point at your accommodation you can also visit your itinerary stops over the WIFI connection and have those maps cached when you are out and about.Tip 5: Download offline transla tion applications.o most of us will be familiar with the free applications such as iTranslate which uses Google translate over your Internet connection to translate between languages. When abroad this data transfer can be costly. I have found that paying a few dollars or pounds for the offline version of the software which includes phrases and vocabulary is much better and performs significantly faster.Please note that these are only a small extract of tips for traveling with your iPhone from iPhoneTutorialVideos.comThere are many more techniques available that will help you use your iPhone when abroad and you would be surprised with the results that this little computer in your pocket can achieve once you get to know its secrets.As a teaser I will leave you with the following questions to think about:How can carrying toothpicks in your travel bag help you and your iPhone out of a uncomfortable situation? Is it possibly to put a local simcard in your iPhone when abroad WITHO UT jail-breaking your iPhone? Have you ever wanted to listen to your mp3's on your iPhone while snorkeling in the Great Barrier reef?With these few tips I hope your experience of using your iPhone while traveling abroad or maybe even the world will be more enjoyable.

access point vs router

Why Wireless Internet Service is Always Better than Wired Internet? - Technology - VoIP

There are so many people who actually forget about what is wired internet. Today, the world has been changed. Now it is the time of technology and advancement. No one wants to see a bundle of wires spread around in your room. Wireless internet is become a part of our life. This is because no one has enough time to attach a wire and stick at a place for using internet. This is the most important reason of why many people are moving from wired internet to wireless internet. But still there are some specific people who use wired internet service. This is because there is no best Internet service provider available in that area where they live. Also there are many people who only allowed to use dial-up service in their immediate area and if these people want to go wireless many times they have only one or two Internet providers that are willing to provide them with service. This is something that many are unaware of until they begin gathering information.For these kinds of peo ple who are using a high speed internet via a cable or wire then there is only one option left if any wireless service is not available in that area is through a wireless router. This is the best alternate for a wireless internet service in case you are completely bound for using a cable internet. This option allows you to use your internet at anytime any where you want. But you only need to take care of the limit because a wireless router only offers its services for a limited area. But the truth is everyone has its own choice and option. You cannot force to choose what you like. But if a wireless internet connection offers you high speed internet then it is better to switch from cable to wireless. This is because wireless internet is much reliable and reliable and can attain higher speeds, having a wireless internet access card through a company can allow you the freedom to access the internet even when you are not at home and even when the power is out. This is really a g ood option for those who regularly use internet and cannot afford low internet connectivity. There are many different options available in the market. You will be a lucky one if you live in that area where good internet service is available you'll most likely select a high-speed service that runs with a wireless router to allow internet to flow freely through your residence or company. So if you want to experience high speed wireless internet then just make a little search about who can offer you best and affordable rates. Also you can search online for internet service providers. There are many different providers for your Wireless internet connection and various ways to utilize this connection to it's fullest. To learn more about wireless internet just make a visit at IT depot online and get your wireless service today.

it depot online



access point vs router

vineri, 29 noiembrie 2013

Wi-fi Wireless Internet Made Simple - Computers

Just what is all this Wi-Fi wireless internet stuff they are trying to confuse and torment me with?

It is actually quite simple, useful and most of all convenient.

All you probably want to do is to share your internet connection throughout your home whether it be to other computers or so that you can sit in your bedroom and wirelessly surf the internet or send email. Perhaps as well you wish to share files such as songs throughout the computers in your house, apartment or condo.

Don't let them confuse with all this alphabet soup - b, g, a, 11 megabytes, 54, 108.

To begin with most any of the systems are beyond overkill. All will go faster than the even high speed broadband internet. Most use the same frequency as the standard cordless phones (2.4 GHz).. Be reassured the phones and the wireless internet in most cases will co- exist and work well with each other.

The most common wireless setups wireless b and g use the frequency most cordless phone use. G wireless internet is sort of a faster b standard. What is important to know is that it is all standardized. B will work with G and G products will work with B. G is said to up to 5 times faster than B that is assuming that you are relatively close. G wireless is very useful primarily if you are sharing large files between computers. For ordinary browsing b wireless is still overkill speed, faster as said than most broadband internet connections. The usual stated range of these wireless products is 300 feet indoors range and 1000 feet outside. The range is basically line of sight. Heavy dense objects - primarily metal, metal doors, metal foil insulation, heavy bricks and pipes and objects such as furnaces, metal filing cabinets will block reception to some degree. As well if the manufacturer makes some ultra high speed claims remember that both the router and wireless network adapt ers will have to be that brand and that special computer networking hardware feature to work at those high speeds and transmission rates. Remember to that wireless internet transmission speeds fall rapidly with distance.

Wireless internet is basically a radio setup with a transmitter and receivers. The transmitter is a box that plugs into the internet to share your internet connection. This is called a "Router ".. Wireless routers are made by a number of manufactures and the most widely known are the Linksys and D-Link brands. All routers are fairly good now. Tech support may be something to consider for setup ease. Routers are often sold on sale at big box stores as a means of drawing customers who already have at least one computer into their stores. It is reasoned that if a customer wants to buy a router the odds are good that he or she has more than one computer and once in the store will make additional purchases.Perhaps they will be even so fed up with the older computer as the kids have taken use of the newer faster model that the customer will even buy a additional new computer from the store.. The routers that you will find on sale will most likely be the newer g standard routers which will work with your B or G wireless network adapters in your computers.

Secondly you will need a receiver to receive the wireless internet signal at the computer end. You will have several options depending on your setup. If your laptop is a newer model then you may have a wireless "network adapter:" already built into your laptop. If you have an older laptop you can install a PCMCIA wireless network adapter into the credit card sized slot on your laptop. If you have a desktop computer you will have several options. If you have the abilities and are allowed by your warranty to open your computer case then you can install a standard PCI wireless card. The advantage of the PCI cards is that they almost always work, are screwed in so that they cannot be dislodged to stop working. The disadvantage is that the antenna of the card is hidden behind the metal of the computer case limiting reception. Another option is USB wireless adapters. Not only can the USB wireless adapter be installed without opening the case but as well with a USB extension cord the YSB network adapter can be lifted away from the computer to a higher more open place.

Several points on setup to make your life easier. After all networking is often called "Voodoo Science ". First if you are buying both the wireless adapters as well as the router try to buy the same brand, There will be easier setup, perhaps faster speed and tech support will not be able to blame the other vendor's product for setup issues. You can tell tech support even after the return period of the store: "I guess the products are defective and have to be replaced ". There will be no issue of blaming the other vendor's product. Case closed. Secondly most of the routers are setup by a "web based interface ". Some will come with an install disc as wizard. With others you will enter a web address usually 192.168.x.x and a password. To enter this setup interface. The instructions and passwords should be in either your instructional manual or disc that came in the box with your router. If you have a standard cable broadband account then just follow instructions if you have a DSL type of broadband internet connection then you will need the paper the phone company gave you with your internet account name and setup password. The type of connection that you set up in the router for DSL connections is called "POPE" The connection internet connection password is most likely different than your email password. This internet connection password is of very little value to anyone else. If you do not have this information phone your DSL provider tech support.

Next install the wireless adapters. Windows XP has its own wireless utility program installed. With previous versions of windows (Windows 98, 2000 and ME) you will have to install the utility program that the manufacturer provided on the install disk.Most of his install manuals have 2 different sets of instructions - one for Windows XP, the other for the remaining operating systems.

When you setup the router you will be given a choice of whether to turn on the security features so that other people can drive up in front of your house and freeload your internet signals. It is anyone's choice whether they wish to use this feature or not.Believe me there will be no shortage of wireless internet connections for those freeloaders - estimate is 60 %. You can say to yourself if someone wants to waste gas to sit in front of my home to download songs or whatever good for them. If you wish to turn on the scrambling to sign onto your internet it will be in the advanced wireless or wireless security section of your router control panel. There are a number of choices. Most common is a setup called "WEP" (Web Enabled Protection)... This is available in a standard 64 bit or more secure 128 bit WEP settings. 64 bit setup is easier. 128 bit has you enter a long string of characters twice. Lots of fun with mistakes on entering those digits correctly. The easier to use security setup routines will allow an easy to use phrase code generator. For example in the phrase code generator you enter the wordBadgerlinux. The number / character code will then be generated that you must enter both the router and wireless adapter ends of your system. WEP is considered by purists not as secure as a newer system called WPA. Not all of the older hardware supports WPA. You may look at it as - if someone in my area can break into my WEP protected wireless system then that is the least of my troubles.

Lastly the biggest problem with wireless internet networks in neighbors. That is right neighbors. It is estimated that 40 % of wireless products are returned to big box stores. There are 12 available channels available in the wireless router settings. For convenience and to aid setup most brands of routers place the default channel of their routers as channel 6 right in the middle of the 12 channels available. It does not take much a signal at all to confuse your wireless adapter. You will see signal strength of your wireless route signal but you will unable to get a solid internet connection.Worse yet this phenomenon of no internet connection may be sporadic. In many cases you will not be able to even spot the culprit in your wireless configuration software.Remarkably wireless internet signals can travel a fair distance and may even appear to come out of nowhere. Worse yet the interference may be on sporadic. And as said it does not take much of a signal at all to leave y ou with no internet connection.

The answer is simplicity itself. "Change the Channel ". There are 12 available channels in your router setup control panel. The next 2 choices for wireless channel selection are at the 2 ends of the spectrum - channels 1 and 11. However it may simply be a matter of trial and error.

Wireless internet is rather amazing, you can surf the world, download songs, send email and transfer files conveniently at high speed and at some distance away from your internet connection. In addition you do not have to call or pay electrician to string the internet network wiring in your home. And if you wish to move the computers or even move just pickup and make the move.

If in the end you are having troubles on setup do not feel afraid to call tech support. Someone in India or the Philippines will be more than happy to assist you. Remember in the end you have the ultimate threat of all, that is to take your new Wi-Fi wireless products back to your store of purchase.

Max Z. Rubin Agricultural Chemist Linux as well as vintage computing ://



access point vs router

Picking the Right Cable Internet For Subscribers

If the cable internet is your option to get online, then you should know that most companies use the Ethernet products in their cable high-speed internet plans. In this situation, you must identify the type of existing Ethernet network or the type of network you wish to configure. Every type of network you can have uses a particular equipment, such as an Ethernet router to connect the elements of the network. Such a network created through cable Internet is known to be an infrastructural network. It ensures reliability, security and superior performances.The Ethernet cable high-speed internet networks may or may not be connected. If you place your equipment in a connected network, you are recommended to use a gateway, so the IP address of your extra equipment to be dynamically assigned through the DHCP protocol. A gateway can be a router or a Windows based computer that runs ICS - Internet Connection Sharing. Most cable Internet plans are not so detailed in their descript ions, since a lot of people cannot really understand these aspects, therefore they don't care too much about them. An advanced user can always ask about these details and choose whether to configure everything at home, without help, or just get a professional from the provider to do the whole operation.There are two types of Ethernet connections with cable Internet. If your network has access through cable Internet or DSL, you can use a router or a computer as an Internet gateway. In both these situations, you have access to all the features of your extra equipment. With a router as a gateway, the router manages the connections and a cable Internet or DSL modem provides access to the Internet. Using this configuration opens more possibilities for other devices.With a computer as a gateway, the network equipments are connected to a commuting device or a router. A computer in the network has the role of a gateway. It has to use ICS or a similar software to part the connections and provide access to Internet to the other equipments, everything through cable Internet. If the gateway computer is turned off, the other computers lose the access to the Internet, which is a big disadvantage.Reliable cable Internet deals should be generally able to provide their customers with any of these options, as long as they opt for wired cable Internet plans. Each option brings in both advantages and disadvantages. Is it worth getting a router? Or just maintaining one of the computers open all the time? Most customers would agree that making a small investment in a router is the better option. First of all, you don't really depend on another computer, especially when you encounter small power cuts and second of all, the gateway computer will work faster if there are not as many other computers connected to it. The other cable Internet option is the cheap one and therefore, it is not too popular, although it is a lot more secure and faster than using a router.
access point vs router

High Performance Netgear Dual-band Routers: Which One is Best For Your Need

Netgear has introduced several new wireless n routers since the IEEE approved the draft version of 802.11n standard. Netgear also redesigns existing routers to comply with the ratified version of 802.11n standard. Currently there are five wireless n dual band routers (one with built-in DSL modem) which are designed to meet high-performance category routers for fastest downloads, smooth gaming and better streaming video. They are WNDR3300 dual band router; WNDR3400 N600 dual-band router; DGND3300 wireless n DSL router; WNDR3700 wireless gigabit router; and WNDR37AV wireless router for gaming and video. WNDR37AV is believed for future replacement for WNDR3700 router.

WNDR3700 and WNDR37 routers are almost similar except that WNDR37AV supports Windows 7, Live parental control, and DLNA compliant. DGND3300 is designed with built-in ADSL modem � a single solution for home wireless network environment. Now let's have a look the comparison between the three routers WNDR3300, WNDR3400, and WNDR37AV.

Wireless Standards

All the three wireless routers are designed with simultaneous wireless �n dual-band to work with both 2.4 GHz and 5 GHz frequency bands. All routers are compliant with wireless a/b/g/n devices. With dual-band, the system provides double bandwidth for faster speed.

LAN / WAN Interface

All the three wireless routers are embedded with 4xRJ-45 LAN port and 1x WAN Ethernet port but only WNDR37AV router is embedded with Gigabit ports for both LAN and WAN interfaces. All ports are Ethernet with auto-sensing, means the port can detect the network cable either cross or straight-through type and can adjust the signal automatically to match the cable type accordingly. You don't need to worry in selecting the cable type; both cross and straight-through cable can work.

USB Port

Both WNDR37AV and WNDR3400 routers are embedded with the USB port which can be used as the storage server. Netgear with ReadyShare technology provides fast and easy shared access to an external USB storage device. WNDR37AV features a DLNA (Digital Living Network Alliance) Media Server allows you stream video and music from a USB drive to media players, DLNA TVs, and any other DLNA compliant devices without the need to turn on the PC.

WNDR3300 wireless router does not include the USB port. This is one of the con sides of this router compared to other WNDR37AV and WNDR3400 routers.

The disadvantage of the three routers regarding the USB port is that they do not support the USB Printer for sharing. If you require the routers that support USB printer for sharing, you can consider the new Belkin including Share, Play, and Max Play wireless routers. Or you can consider the TEW-673GRU wireless router by Trendnet. TEW-673GRU is an all-in-one solution for wireless router, storage, and print server.

Advanced Security

All the WNDR3300, WNDR3400, and WNDR37AV routers support the latest wireless encryption Wi-Fi Protected Access (WPA/WPA2 - PSK) and WEP (Wired Equivalent Protection) for connecting to legacy wireless clients. For network protection, NAT & SPI firewall and VPN pass-through for secure tunneling are also included.

The �free live parental control' and �guest access' are the distinct security features for WNDR3400 and WNDR37AV compared to WNDR3300. WNDR3300 doesn't support the guest access and free live parental control. With guest access, you can create specific SSID for guest separate from your private network. With live parental control, you can block bad sites for your kids and you can manage remotely from anywhere.

System Requirement

All the routers support Microsoft Windows Vista, XP, 2000, Mac OS, UNIX, or Linux. WNDR3400 and WNDR37AV also support Windows 7, but WNDR3300 does not. Other requirements are the same.

Netgear Green Technology

Except WNDR3300, both WNDR3400 and WNDR37AV support Netgear Green technology. With green technology, the routers are designed with eco-friendly to help conserve the energy including power/wireless on/off buttons, 80% recycled packaging, energy star compliant power adapter etc.

Both the prices of WNDR3300 and WNDR3400 are under $80 currently, but for WNDR37AV currently the price is around $140. Now which one do you need for your home wireless environment? Unless you require high-performance environment for video streaming and gaming more enjoyable and you also require Gigabit for fastest wired connection, you can consider WNDR3400 which is around 70% cheaper than WNDR37AV. Otherwise, consider WNDR37AV wireless n dual-band router.

By Ki Grinsing



access point vs router

Wireless Networking - Improving Video over Wireless Network Performance

Overview

This article discusses how to improve video over wireless performance. Many companies are using various new video content technologies today such as live video streaming, webcasting, video conferencing and web conferencing. YouTube services continue to be popular and are using increasingly more bandwidth as companies use video for training and marketing purposes. Google language translation service can now convert text, making the English text based videos available to other countries as well. Keep in mind that with the proliferation of company VPNs for security purposes, employees can use wireless at work as seamlessly as at home or on a public network. They can access the same video services from anywhere. This is why wireless is so popular now and the need for video grade wireless infrastructure performance.

The current 80.11a/g wireless access point is easily swamped when several clients start downloading large files and running video applications. The best solution for guaranteeing acceptable video performance is now the 802.11n wireless standard. According to a Cisco forecast study, the number of wireless devices will exceed wired devices on the internet by 2015 and account for 54% of IP traffic. In addition video traffic will account for 90% of the consumer internet traffic by 2015.

Video Basics

Video and voice are real-time traffic streams by nature that are sensitive to network congestion that causes latency (delay). Video has both a data and an audio component. It should be noted that the same performance metrics such as jitter, latency, packet loss and throughput affect video as well as voice traffic across the internet and company network. Packet loss has a greater effect on video while latency affects voice much more. Guaranteeing specific service levels for video on the network could involve implementing QOS, increasing network bandwidth, network design changes and equipment changes. All these improvements are for the purpose of making the network "video ready". Companies increasingly use web conferencing, webcasts and video conferencing for meetings and for training purposes. Colleges use it to deliver courses as well. It is a very cost effective tool to decrease company travel costs.

Types of Video

It is worth discussing the various types of video services popular today and where, from a networking perspective, consumers source the content. Note how most of the services are across the internet.

�Live Video Streaming over the internet of company Webcasts and TV broadcasts typically delivered to your desktop.
�Web Conferencing to the desktop with applications such as Skype and the very popular Go to Meeting service.
�Video Conferencing service that runs from and across the company network with Cisco Telepresence and equipment from companies such as Tandberg and Polycom.
�Progressive Video download from companies such as YouTube to the desktop.
�Broadcast Video multicast of one to many video streams such as Netflix.

Video Performance

H.323 defines a suite of protocols for audio and video traffic including H.264 and G.729 protocols. It is a framework for developing multimedia applications on a company network. The G.729 protocol is a popular audio codec for compressing audio traffic at 8 Kbps with a 10 ms delay. The H.264 video codec standard is the most current adopted video compression standard. It specifies 24, 30 and 60 frames per second (fps) for high definition (HD) video conferencing with compression from 1.5 Gbps of video traffic to 4 Mbps at a resolution of 1920 x 1080 and 30 fps.

It is important to understand the performance metrics that affect video performance including packet loss, latency, jitter and throughput. Video is sent as a constant stream of traffic in contrast to data traffic such as email that can be re-transmitted with some delay and have no significant effect on service level. Congestion is the basic symptom of a network that is busy and experiencing network performance problems. The queues are busier during times of increased network activity. This causes increased latency, jitter, packet loss, decreased throughput and re-transmission of packets. Implementing quality of service (QOS) will sometimes actually cause dropped data packets to prevent voice/video packet loss. The data packets are then re-transmitted with some delay. The following defines these industry standard performance metrics.

Latency: Amount of time for a packet to travel from source to destination

Jitter: Amount of average variation in latency of each packet

Packet Loss: Percent of packets dropped from source to destination

Throughput: Average number of packets sent during a fixed period of time

Each video service requires different amounts of bandwidth. Some services such as video conferencing are more affected by increased latency, packet loss and jitter than desktop applications. For acceptable video conferencing performance, the packet loss should not exceed 1%, jitter 30 ms and a one-way latency of 300 ms (latency of 150 ms for high definition video conferencing resolution). When these thresholds are exceeded the picture can deteriorate. Bandwidth requirements for video are linked to the specific type of service, amount of resolution and frames per second. For example a standard video conferencing resolution of 704 x 576 at 30 fps requires 768 Kbps - 1 Mbps of bandwidth while a High Definition (HD) resolution of 1080 x 1920 at 30 fps requires 4 Mbps - 12 Mbps. Desktop services such as streaming video and web conferencing have lower bandwidth requirements than video conferencing, however the same latency, jitter and packet loss problems affect video performanc e. In addition with all services, you have to add an average of 20% additional bandwidth overhead for Ethernet and IP protocol processing.

Video Quality of Service (QOS)

Implementing quality of service (QOS) on a company network is an end to end process starting with the video stream source. Video conferencing end points are often connected to a company edge switch while video streaming to the desktop is internet based. The process of implementing any QOS involves prioritizing traffic for preferential service. Considering video conferencing, the Cisco 3560 and 3750 access edge switches are often used to connect video equipment. The layer 2 data frame has an 802.1p header with 3 bits that can be set for 8 different class of service (CoS) values from 0 - 7. For instance video is assigned CoS of 4 while voice packets are assigned CoS of 5 and the higher number gets better service. High priority data is often assigned CoS of 2.

DSCP is a layer 3 QOS protocol used to specify various types of service (ToS) classes for data, voice and video traffic. DSCP values are layer 3 and as such are set in the first 6 bits of the IP Precedence field of the IP header. The best practice recommendation from Cisco for marking video is a DSCP of AF41. Data traffic is assigned a lower priority such as AF21 for instance while voice is assigned a higher priority of DSCP EF. Video traffic is classified with access lists that define video traffic and a class map is defined for video that matches an access list and points to a specific policy map. The policy map does the DSCP marking of video traffic and the DSCP value is assigned to a queue. Class of service (CoS) packets can be set with a policy map however it is often marked at access switches with SRR and with WRR at distribution/core switches.

Shaped Round Robin (SRR) is a hardware based queuing technique deployed with access switches. SRR allows layer 2 class of service (CoS) and layer 3 (ToS) mappings to queues. The distribution and core network layers typically have 6500 Cisco switches and they use Weighted Round Robin (WRR) hardware queuing. WRR is the same idea however the queuing architecture is somewhat different and only layer 2 class of service values are mapped to queues.

WAN routers are deployed with Low Latency Queuing (LLQ) and Class Based Weighted Fair Queuing (CBWFQ) that assigns video traffic to the high priority queue with a specific priority percentage such as 15%. That guarantees all video traffic will get 15% of the link bandwidth. For instance a 1 Gbps Metro Ethernet circuit will allocate 150 Mbps of bandwidth to video traffic minus protocol overhead. Company WAN links as a best practice should never exceed approximately 33% of available bandwidth for all voice and video traffic. That leaves room for protocol overhead and data packets. Data traffic performance worsens as packets are dropped and video traffic QOS becomes less effective.

Desktop applications use the same QOS tools however the company internet connection and the wireless network factor into the design. In addition the public wireless network you happen to be using affects the overall video network performance. The bandwidth of your home internet connection and congestion affects performance as well as any congestion points across the network. The wireless network is most often where video performance degrades particularly on an 802.11b public network.

Wireless Standards

These describe the industry standard wireless protocols currently deployed.

80.11b

This wireless standard approved in 1999 specifies a maximum data rate of 11 Mbps using the 2.4 GHz unlicensed band in the United States. The band experiences a lot of interference from commercial devices using that frequency. The standard in the United States assigns 11 channels with bandwidth of around 80 MHz at 5 MHz per channel. The United States allocates 3 non-overlapping channels of 1, 6 and 11 with a center frequency separation of 25 MHz per channel. The modulation scheme used with 802.11b is Direct Sequence Spread Spectrum (DSSS) with CCK with characteristics that minimize effects associated with interference. The 802.11b additional data rates include 1, 2, and 5.5 Mbps.

802.11g

This wireless standard approved in 2003 specifies a maximum data rate of 54 Mbps using the same 2.4 GHz band as 802.11b. The 802.11g standard is popular with higher throughput and increased coverage. The same interference problems occur however with the 2.4 GHz band. The 802.11g is compatible with the 802.11b standard and assigns the same 11 channels with 1, 6 and 11 as non-overlapping. The modulation scheme used with 802.11g is OFDM that specifies higher data rates. The additional 802.11g data rates include 1, 2, 5.5, 6, 9, 11, 12, 18, 24, 36 and 48 Mbps.

802.11a

This wireless standard was approved in 1999 specifying a maximum data rate of 54 Mbps using the 5 GHz unlicensed band in the United States. The advantage of 802.11a is higher throughput however the cell coverage is smaller and additional access points will be needed for the same 802.11g coverage. There is much less interference from devices such as cordless phones, bluetooth devices, microwaves and commercial devices using the 2.4 GHz band. There are 23 non-overlapping channels with the current 802.11h specification. Some Cisco devices support both 2.4 GHz and 5 GHz transmitters on the same access point. The modulation scheme used with 802.11a is OFDM, with higher data rates and minimizing effects of interference. Each country specifies the number of channels and frequencies it allows with the 5 GHz band.

802.16

This is a metropolitan (MAN) wireless standard that provides home and business clients seamless wireless access from anywhere. The line of sight technology specifies a distance of around 27 miles and speeds of up to 120 Mbps. The point to multipoint specification operates in the 10-66 GHz range. There is an 802.16a specification with mesh topologies and non-line of sight with frequencies from the licensed and unlicensed 2 GHz and 11 GHz band at a speed of 70 Mbps. The key problem with any MAN implementation using unlicensed frequencies is interference from similar devices.

802.11n

The new 802.11n wireless standard approved in 2009 defines much faster data rates of 300 - 600 Mbps and 1000 Mbps from access point to network switch increasing throughput from client to access point and access point to network switch. It operates in both the 2.4 GHz and 5 GHz bands with effective new performance enhancements such as multiple input multiple output (MIMO) and channel bonding.

Wireless Contention

Access points are essentially a less efficient hub style shared media device with a flat broadcast domain. Contrast that with a Cisco Ethernet switch that has 100/1000 Mbps bandwidth per port and broadcast segmentation with VLANs. The switch uses a much more effective media access contention scheme than wireless access points. The wireless network employs an older less effective carrier sense multiple access with collision avoidance (CSMA/CA) process to manage client access to the network. The effect of CSMA/CA is increased bandwidth usage, packet loss and packet re-transmits with this shared media. In addition there are the standard wireless problems with the 2.4 GHz band interference and multipath signal fade that occurs when the signal bends or is distorted by the building structure. From a practical perspective 15-25 wireless clients can associate with a single access point at anytime and still maintain good performance. This of course changes as more video and high ba ndwidth applications are used. The 802.11n can actually support all of those clients running simulataneous live video streaming with 14 of them running high definition video streams.

Data Rate, Distance and Frequency

So by now you know there is no warp speed with older wireless. Data rate (speed) and performance metrics decrease as the wireless clients move further from the access point. Beyond an average of 50-60 feet, the speed decreases and latency, packet loss and jitter increase. The wireless network site survey determines where and how many access points should be deployed so each cell (defined coverage area) has a signal strength with 54 Mbps. The coverage area can be extended with a stronger directional antenna. For instance, these are approximate rated distance, speed and frequency specifications indoor for the Cisco 1240AG access point. Note the 802.11a distance is typically half that of an 802.11g radio however this rating was with a stronger 3.5 dBi antenna.

802.11a (5 GHz): 54 Mbps @ 60 ft - 80 ft with 3.5 dBi omnidirectional antenna

802.11g (2.4 GHz): 54 Mbps @ 80 ft - 100 ft with 2.2 dBi dipole antenna

As the data rate increases your effective network range decreases. Clients that want a continuous maximum bandwidth will need to deploy more access points per design. Increasing transmit power will actually decrease network range at higher data rates while increasing the range with lower data rates such as the case with 802.11g access points. The problem is with increased transmit power, the receiver sensitivity decreases with a process called error vector magnitude. That doesn't apply to the wireless clients where transmit power should be set at maximum for best results. The network length or wireless maximum distance is around 100 meters from client to access point, and with Ethernet wired designs 100 meters from access point to switch. The campus design can be extended with additional switch - switch connectivity of course.

Wireless data rates specify maximum throughput however that isn't a practical value. Mixed environments such as 802.11b and 802.11g will decrease throughput for both clients on the same network segment. As mentioned the 802.11b and 802.11g clients are compatible and can associate with the same access point using the 2.4 GHz band spectrum. Throughput for 802.11b is around 6 Mbps however that will vary with antenna type, distance from the access point and transmit power. Configure the access point with 54 Mbps for 802.11g clients and basic 11 Mbps for the 802.11b clients. That prevents the access point from operating at less than 11 Mbps. Some access points can operate with dual band 802.11a and 802.11g however they are separate logical networks and must have separate wireless site surveys. The 802.11a access point uses the 5 GHz frequency band. As frequency wavelength increases the network range will decrease. The design with 802.11a covers much less distance compared with 802.11g at the same data rates. The higher frequency (5 GHz) signals don't pass through the building structure as easy as lower frequencies.

These are some average bandwidth throughput values and associated wireless standards. From a practical perspective all 24 channels won't be available with the 802.11h standard and 802.11a access points due to channel overrun interference. Note the effect of mixed environment wireless equipment such as 802.11b/g on the same network and decreased throughput. This occurs as well when there are 802.11n access points with older access points on the same network.

802.11b - 6 Mbps x 3 channels

802.11g - 22 Mbps x 3 channels

802.11b/g - 8 Mbps x 3 channels

802.11a - 25 Mbps x 21 channels

802.11n - 150 Mbps/300 Mbps x 21 channels

Decreasing the transmit power of an access point will minimize channel interference. The effective network range can be extended with repeater access points, increasing access point transmit power or adjusting the access point position. Using a higher gain antenna on the access point is an option as well. Cisco access points have a lot of options for deploying antennas with higher gain and sensitivity. Note you should minimize the cable length of any antenna. The longer antenna cabling will attenuate the signals. Some countries limit the maximum access point transmit power setting.

RF Propagation

As mentioned signal attenuation is worse at higher frequencies. There is however a lot of environmental factors that distort, bend and minimize signal strength. The result is something called multipath fading where a signal takes several paths to a destination. These are some examples.

� Diffraction - signal bending due to building structure angles

� Refraction - environmental factors such as humidity can cause signal to bend

� Reflection - water, glass or any smooth surface can bounce a signal distorting or fading it

� Absorption - structures absorbing signal (trees)

� EMI interference - cordless phones, microwave ovens, electrical motors, bluetooth devices

Fade Margin is the amount of receiver sensitivity power that can be decreased while maintaining acceptable network performance. That is a factor with deployment of outside wireless bridges with point to point topologies such as buildings on a campus. Problems with rain will attenuate signals and knowing the fade margin will avoid performance issues. Polarization is the orientation of the radiated pattern from the antenna and like a key must match with transmitting and receiving antenna. The most often polarization used with access point antenna is linear. Antenna can transmit horizontal or a vertical polarized signal.

Improving Video over Wireless Performance

When discussing bandwidth requirements and various video services it is important to note that a wireless network will always require much more bandwidth than your company LAN or your home internet connection for the same video service. An example is high definition live video streaming where the actual wireless bandwidth needed is much higher compared with the LAN or home cable/DSL internet connection. The home internet connection would require 500 Kbps - 1 Mbps. That is not a problem even for home internet where the cable download speed is an average 10 Mbps. The wireless network with access contention and multipath fading problems aren't as efficient and would use an effective bandwidth of 5 - 10 Mbps. In addition, note that packet loss does affect video over wireless performance more than latency and jitter however all metrics can be improved with the following recommended improvements.

1. Deploy the new 802.11n Access Point and Client Adapters

The new 802.11n wireless access point is now rated at 300 Mbps with the new feature enhancement. That is 6x faster than the nearest 802.11g standard. Deploying 802.11n in the 5 GHz band and you have 21 non-overlapping channels available as well. That allows for higher data rates per coverage area. The new enhancements include multiple input multiple output (MIMO), channel bonding, MAC block acknowledgment, payload optimization and unicasting and QOS prioritizing of traffic classes.

MIMO Explained

802.11n uses multiple input/output antennas on the access point and wireless client to increase data rates and decrease re-transmits and packet loss. The access point and clients can send simultaneous traffic streams increasing the amount of data and extending the network range (distance). The current most popular Cisco 1250 AP uses what is called a 2T x 3R MIMO. That is 2 transmit antenna on the access point and 3 receive antenna on the client. The best results occur when all wireless clients use 802.11n adapters and access points are all 80.11n with no mixed environment of 802.11a/g access points.

Channel Bonding

The technique of channel bonding now allows combining of 2 non-overlapping channels in the 5 GHz band to send data at 2x the standard data rate for a theoretical 300 Mbps. In practice the average data rate has been tested at 180 Mbps and 140 Mbps for video streaming. That is pretty impressive compared with 802.11g average throughput of 22 Mbps.

Payload Optimization

The feature of payload optimization or packet aggregation is basically putting more data in each packet sent resulting in more effective use of the transport media.

MAC Block Acknowledgment

Previous access points required that each MAC layer MPDU packet was separately acknowledged with an ACK packet. The new 802.11n standard now uses a single block ACK to acknowledge multiple MPDUs. This decreases the amount of protocol overhead and less bandwidth required.

Multicast to Unicast Traffic

Video over wireless presents a specific problem with multicasting that the wired world doesn't have. Wireless access points do not support multicasting however 802.11n can now convert multicast to unicast streams per wireless client at layer 2.

2. Network Design

The wireless access points should always be connected to a 100 Mbps full duplex switch port. The 802.11n access points should be connected to a 1 Gbps or 10 Gbps switch port. Video end points should be connected closer to the distribution layer and on a less busy line card. The end point video source equipment can be located at the network edge as well, however you should select a switch with all the performance features and preferably located in the data center. Wireless multiple SSIDs should always be defined to segment traffic and assigned VLANs to match the same VLAN schema implemented on the wired network.

Use a hierarchical design with any new wireless/wired deployments and where possible spread out and connect access points across multiple network switches instead of a single switch. Consider doing some performance monitoring on the network to eliminate media mismatches. For example a network switch with a Gigabit port that is uplinked to a switch with a 100 Mbps interface. As well WAN circuits are most often the slowest link compared with the switch infrastructure.

�Have a proper wireless network site survey done for each band to minimize signal overrun and optimize coverage.
�Deploy internal client adapters instead of external USB style at your laptop for best performance.
�When deploying 802.11a/b/g access points (mixed environment) with 802.11n access points, it is better to assign the 802.11n access points and clients to the 5 GHz band where there is more non-overlapping channels and less interference.
�Use all 802.11n access points and clients where possible instead of mixed environment and at least 2T x 3R x 2S spatial streams.
�Use additional access points per coverage area with 802.11n at 5 GHz for increased data rate, range (distance), number of clients and network availability.
�Deploy more powerful extended range antennas to increase the data rate and range.
�Clean up problems with any sub-optimal routing on the network.
�Consider deploying the WLC 4400 WLAN controllers. This requires a f irmware upgrade on all 1100 and 1200 series autonomous access points, however there are advantages such as advanced RF management features.

3. End to End Quality of Service (QOS)

Any good quality of service deployment must consider both wired and wireless QOS techniques for guaranteeing end to end performance. The wired QOS has already been discussed here with Shared Round Robin (SRR) and Weighted Round Robin (WRR) hardware queuing on switches. As well there is Low Latency Queuing (LLQ) and Class Based Weighted Fair Queuing (CBWFQ) implemented on WAN routers. DSCP and CoS packet marking is used to prioritize specific traffic types for preferential queuing. Wireless now has Wireless Multimedia Extensions (WMM) that classifies traffic with 4 categories according to traffic type. These include voice, video, best effort and background. This provides a guaranteed service level for video traffic during times of network congestion.

The layer 2 data frame from the switch has an 802.1p field where the class of service (CoS) bits are set. The access point examines that field and queues traffic with a specific CoS setting to the assigned queue. The voice traffic queue is the highest priority queue and any traffic queued there is serviced before video and data. Any wireless clients not using VoIP will have video prioritized first. Note that although queue 3 best effort has a CoS of 0 that queue is still higher priority than background traffic. Cisco VideoStream application layer enhancement allows assignment of video traffic to a priority stream according to a VLAN or SSID assignment for preferential queuing.

Access Point Priority Queuing:

Queue 1: Voice Traffic CoS = 6,7

Queue 2: Video Traffic CoS = 4,5

Queue 3: Best Effort (Transactional Data) CoS = 0,3

Queue 4: Background Traffic (Email) CoS = 1,2

Call admission control is a type of QOS that limits the number of video sessions to avoid oversubscription of the priority queue at the switches and routers. The use of a gatekeeper service monitors the number of video sessions and denies any additional sessions based on the bandwidth setting of the queue. The priority queue is configured with enough bandwidth for a specific number of sessions and any requests for additional sessions are denied if that exceeds the queue size.

4. Bandwidth

As mentioned, doing a performance assessment of the current network will identify where additional bandwidth is needed. The company WAN is the most common source of problems with bandwidth. The prevalence and low cost of Metro Ethernet Gigabit circuits today make it is a great opportunity to deploy it on the company network.

Shaun Hummel is the author of Network Planning and Design Guide and featuring Networking Books, eBooks, Certifications, Articles and Design Tools.

Copyright 2011 Shaun Hummel All Rights Reserved



access point vs router

Virtual Private Network Frequently Asked Questions

1. Why do I get disconnected after 4 hours of use?(a) You will get disconnected because of the limited number of ports and the fact that 90% of all users do not need to be connected more than 4 hours, all units have been set to a 4-hour time limit.(b) If you require more time, you should disconnect gracefully before the time limit and reconnect so that you do not lose your work.2. Why not use an 800 number all the time?(a) Using an 800 number costs the corporation 5 cents a minute versus calling a local number when available that costs 5 to 7 cents one time charge to initiate the call with no per minute charges.3. Do I have to be connected when Email comes in or to prepare Email?(a) No, Email is stored in your server until you need to access it.(b) The proper way to handle Email when working remotely is to make a connection periodically during the day pulling your mail down and then disconnecting.(c) You can prepare your Email in the offline mode.(d) When you make your ne xt connection to process incoming mail all prepared mail can be sent at this time.4. What about reconnection issues?(a) If you are running Windows 95, NT, 2000 or XP making re-connections should be as simple as clicking on the icon to reconnect.5. How do I speed up my dial-in connection?(a) Only install the necessary protocols.(b) Usually IP is the only one needed unless you are accessing Novell Servers.(c) Never install NetBEUI.(d) A good practice, if only accessing Novell Servers occasionally, is to create two configurations, one with IP access only and one with both IP and IPX. Use the second configuration only when required.6. Why can't I see all of the NT units in the Network Neighborhood?(a) When you dial into the Network Access Gateway you are normally on a segment without a master browser, which is how units are displayed in the Network Neighborhood.(b) This does not mean that you cannot access the unit however.(c) If the unit you are trying to access is a member of the corporate WINS structure and you have configured your remote unit per the configuration instructions, WINS will automatically resolve the units IP address when you Map a drive in Explorer.(d) The key to this is to know the computer name and share name that you require before starting the process.7. Why does my Dial-Up Networking fail to work after loading AOL?(a) AOL sometimes replaces the TCP/IP Winsock driver, causing your PC perform erratically or not at all.Fix:1. Delete all references to TCP/IP from the network neighborhood properties.2. Reboot the system.3. Add the Microsoft TCP/IP protocol back in.This will automatically add TCP/IP to all adapters and you should be functional again.8. Can I use Network Address Translation (NAT) to attach my home computers via VPN?(a) In general NAT is not supported by the IPSEC VPN client.(b) Routers such as the Linksys BEFSR11 and BEFSR41 do support VPN with a software workaround.(c) NAT implementations may be used if One-to-One NAT is used.9. Why can't I get higher speed on my 56K v.90 modem into some NAG sites?(a) A 56k v.90 modem is asymmetric by design, so download speed can be as much as 56k but upload speed will be only up to 33.6bps.(b) For 56k to work, there must be only one analogue to digital (A/D) conversion in your local phone loop.(c) Thus when modems at both ends are analogue, 56k speeds will never be achieved as most PSTN exchanges run digital routing.(d) Some NAG sites use analogue phone lines with Cisco and standard 56k modems, while most PCs dialing up use a similar modem.(e) Between both the modems, it limits the download speed to about 33.6kbps maximum.(f) At the same time, many users might experience lower connection speeds due to other reasons, such as more poor line quality.(g) These factors will also contribute to the quality and speed of the line.10. When I load the Extranet Client on my PC and Winpoet is installed on my machine, it crashes or does not work properly.(a) Ther e are known issues running Winpoet software on the PC with the Nortel Extranet (VPN) Client.(b) To repair your system, boot in safe mode and uninstall the Winpoet Software.(c) A simple solution is to have users install the Linksys BEFSR41 hardware router.(d) It has a firmware PPPOE connector, which eliminates Winpoet from the PC and provides the added benefit a NAT firewall for the user with the ability to hook up to three other PCs.(e) A second option is to find a PPPOE Client that does not interfere with VPN Clients.(f) If you have WINPOET, please check with your local ISP to confirm it will work with the Nortel VPN client.(g) If not, or if they are not sure, please do not install the new client, or ask your ISP to find an alternative PPPOE Client that does not interfere with the Nortel VPN Client.(h) If you decide to use Winpoet with the new Nortel VPN client, Nortel strongly recommends using Winpoet 6.0 or higher.(i) Earlier versions of the Winpoet software are known to cause conflicts with the Nortel VPN client.(j) If you have Winpoet on your PC and experience problems (i.e. with an earlier version prior to 6.0) the following 8 steps will safely uninstall the Winpoet Software from your pc and repair your system to boot properly.1. Login to Safe Mode.2. Login under Admin profile.3. Go to Add/Remove programs and uninstall Extranet Client. Do NOT reboot at the prompt.4. Check to see if Winpoet adapter is installed. If so remove it.5. Go to device manager/network adapters. Right click Winpoet or Winport adapter. Uninstall.6. Go to Admin Tools./Services and disable Winpoet-over-ethernet.7. Reboot PC.8. Reinstall the extranet VPN client.An alternative solution is to install the Linksys BEFSR41 hardware router. It has a firmware PPPOE connector, which eliminates the need of Winpoet from the PC.11. My ISP remains connected and I have no known problem with my Internet Service Provider. The problem is intermittent.(a) Check the version of your Conti vity Extranet Access client.(b) You should be using the current release of the client, 4.65 or higher. You can view the most current version by clicking on Current Version.12. I am having problems with my VPN connection.(a) Try isolating the problem by process of elimination.1. Is your Internet connection to the public Internet working properly?2. Do you have the most current version of the Contivity Extranet Access client?3. Have you recently installed any new software or hardware?4. Were any hardware or software changes made since your VPN connection was last working?5. Have you scanned your computer for Viruses?(b) If you are still experiencing problems, try uninstalling or removing the following items.1. Disable your firewall, anti-virus software and any other maintenance or Security programs installed.Try to connect.2. Remove your router from your configuration.Connect your PC directly to your Internet connection.This is accomplished by connecting the cable coming out o f your DSL/Cable modem, directly into your network card or USB connector.If successful, the problem might be your router's setup or firmware.Refer to your Manufacturer's website or documentation for troubleshooting your router or contact the Vendor directly for support. Cheat Note: Caution: use this idea at your own risk - usually there is a little hole in the back of the Router and you can stick a round toothpick into it and push the button inside and it will reset the Router to the Manufacturers settings, do this while the Router is unplugged from any electrical source. This should not upset any of your configurations but do not break the toothpick off inside. It may be best to use a bobby-pin.You must upgrade your firmware.Please beware even though you might have just recently purchased your router, it might have been packaged with an older version of the software.3. Enable your router, firewall/internet security programs one at a time.Cable/DSL users: If you have a dial- up modem installed on your PC, try to test using a dialup connection.Either use dialup to an ISP and then use VPN or dialup directly into your Network.13. The upgrade to release 4.6X of the VPN client failed.(a) Refer to the list below and see if any of this applies:Windows XP Disable the XP firewall.VPN Software Most VPN clients cannot co-exist on the same machine.Windows ME Remove and Add TCP/IP protocol.Brother Multifunction Printer You may not be running the current Brother software for your printer.Windows 2000. Users should download drivers/software from the Brother website.14. How can I remove and re-install TCP/IP Protocol?Below are instructions on how to remove and add TCP/IP for Windows 2000. (Refer to your operating system's help screens, web support and/or documentation for instructions, if you are not using Windows 2000.)(a) Please be sure, no matter which operating system you use, that you elect to restart when finished (as prompted) or restart between each pro cess.(b) For Windows 2000 you must be logged on as an administrator or a member of the Administrators group in order to complete this procedure.(c) Remove TCP/IP1. Open Network and Dial-up Connections, click Start, point to Settings, and then click Network and Dial-up Connections.2. Right-click any network connection, and then click Properties.3. On the General tab (for a local area connection) or the Networking tab (all other connections), click Internet Protocol (TCP/IP), and then click Uninstall.4. In the Uninstall Internet Protocol (TCP/IP) dialog box, click Yes.(d) Install TCP/IP1. Open Network and Dial-up Connections. (Click Start, point to Settings, and then click Network and Dial-up Connections.)2. Right-click the network connection for which you want to install and enable TCP/IP, and then click Properties.3. On the General tab (for a local area connection) or the Networking tab (all other connections), if Internet Protocol (TCP/IP) is not in the list of installed co mponents, then do the following:A. Click Install.B. Click Protocol and then click Add.C. In the Select Network Protocol dialog box, click Internet Protocol (TCP/IP), and then click OK.D. Verify that the Internet Protocol (TCP/IP) check box is selected, and then click OK.TCP/IP is installed as the default network protocol if network adapter hardware was detected during Windows 2000 Setup. You only need to follow these instructions if the TCP/IP default selection was overridden during Setup.15. I am using Windows XP Home or Professional and am unable to get to certain websites or resource servers when connected using VPN.(a) There are some known issues when using the Contivity Nortel client 4.60 on a PC running Windows XP.(b) The older version of the Nortel client (version 3.70) will fix the problem; however, the ultimate goal is to upgrade to the current version.(c) Please do not reinstall version 3.7X as a fix.16. My ISP provider requires the installation of WinPoET. Can I u se it with the latest release of the client?(a) If you are using WinPoET, it must be version 6.0 or higher of WinPoET.(b) Check with your ISP and request v6.0 or higher of WinPoET.17. After installing v8.0 of AOL, I've experienced problems with my connections to my Network.(a) Users may experience problems with Windows Outlook email.(b) You must create two separate profiles; one profile as a Remote Connection (POP3) account for your AOL Internet email and another profile for a local LAN connection to your corporate Network email.Here's how to do it:1. Go to Start, Control Panel, Mail, Services, Show Profiles and Add the second profile.2. Make sure the button "Prompt for a profile to be used" under General tab of MS Outlook properties is selected.3. Disable the ATWPKT2 driver. (The files ATKPKT2.SYS and ATKPKT2.VXD are located in the AOL directory under PROGRAM_FILESCOMMON_FILES.)18. I'm Unable to obtain an IP address while "Hotelling".(a) When working remotely from a Hotel ( Hotelling), you must launch your Internet explorer first and try to obtain an IP address.(b) If you just launch VPN, you won't have obtained an IP address, and VPN may fail.(c) Disable your firewall, as the hotel may recommend.19. Why do I get No Domain Available when dialing my ISP?(a) On your Internet Service Providers (ISP) dial connection, right click the mouse and select the properties button.(b) Click on the Server Type tab and make sure that the "Log On To Network" box is unchecked, otherwise you will hang trying to log into the Network when trying to connect.20. Why do I run so slowly when using my VPN connection?(a) On your Internet Service Providers (ISP) dial connection.(b) Right click the mouse & select the properties button.(c) Click on the Server Type tab and make sure that the NetBEUI and IPX/SPX boxes are unchecked; otherwise you will see delays while the system tries the unsupported protocols.(d) VPN only supports the TCP/IP protocol so checking these boxes will only slow you down.21. Why can't I access my NT resources when using VPN?(a)Windows 95 users should make sure that they have the "Log On To the Network Box" checked in the Extranet Client per the instructions for the Extranet Client Install to use NT resources such as Exchange and file shares.22. Why do I seem to be running slowly through my VPN connection?(a)Try turning off the Software Compression option on your Internet Service Providers (ISP) dial connection as the VPN client has it's own compression. Right click the mouse & select the properties button.(b)Click on the Server Type tab and uncheck the "Software Compression" setting.23. Why can't I get to my Novell Servers when using VPN?(a)VPN only supports the TCP/IP Protocol & most Novell Servers require that you use IPX/SPX to access them.(b)Work with your Novell Administrators to change to NT or use a Version of Novell that supports IP traffic.24. Cannot VPN Web Servers on the Internet after Establishing a Contiv ity VPN Client Connection.(a) Cause:1. This is normal and occurs as a result of having all network traffic passed through the corporate network.2. Typically, firewalls and other security measures on the corporate network will limit your VPN to the Internet.(b) Action:1. The Contivity VPN Switch administrator can set up a default route on the Switch to forward traffic to the Internet.2. If this default route is not configured, you will need to disconnect the Contivity connection to web browse the Internet through your ISP connection.25. Cannot VPN Network Shares After establishing a Contivity VPN Connection.(a) Causes:1. WINS Server may not be configured for IPsec connections on the Contivity VPN Switch.2. Your system may be setup for a different domain than the one on the remote network.(b) Actions:For the first problem, validate that the Contivity VPN Client has been configured with a WINS Server.1. Follow the steps outlined above under "Problems with Name Resolution using DNS Services" to run IPCONFIG at a Command Prompt on NT 4.0 and to run WINIPCFG on Windows 95.2. Verify that a Primary WINS Server is listed under the section for the adapter named IPSecShm on NT 4.0 and on Windows 95.3. Verify that a Primary WINS Server is listed in WINIPCFG for the Contivity VPN Client adapter.4. If there is no Primary WINS Server listed, notify the Network Administrator that the Contivity VPN Switch may not be properly configured.(c) For the second problem, skip the initial domain logon when Windows 95 starts and select "Log on to the Remote Domain" under the Options menu of the Contivity VPN Client dialog box.1. You will then be prompted to log onto the domain of the remote network after the Contivity VPN connection is made.2. This is the recommended method for users with Docking Station configurations.(d) Alternatively on both NT 4.0 and Windows 95, change your workstation to be a member of a Workgroup instead of a Domain.1. From the Start Menu select S ettings then Control Panel.2. In the Control Panel, double-click on the Icon labeled "Network". The Network Control Panel applet will open. Select the Identification tab.3. On Windows 95, the entries on the Identification page can be modified directly, while on NT 4.0 it is necessary to click the Change button to change the entries.4. Change to use a Workgroup and verify that the "Computer name" does not match one that may be on the remote network.5. The name for the Workgroup is not important, so enter anything. Click OK to save the changes and reboot the machine.When accessing a resource on the remote Domain, if you are prompted for a username and password, you will need to have a Domain name precede your user ID.For example, if your user ID is JoeS and you are accessing a machine on the remote Domain named CORP, you would enter your username as CORPJoeS.26. When trying to load the VPN Client on a Dual Processor unit you get an error message.(a) The Nortel VPN Client curre ntly does not support Dual Processor units.27. When I set up my home network, I installed Microsoft Internet Connection Sharing (ICS) so that all of my systems can reach the Internet. Now my VPN client no longer works.(a) The reason for this is that the Microsoft ICS uses Network Address Translation (NAT) to get the Internet connection, and NAT, which may not support IPSec connections.(b) The only way around this currently, is to make the unit running the ICS be the one you run your VPN connection from. Any downstream unit will not be functional for VPN.28. Can Cisco or other IPSEC VPN Client software exist on the same box with Nortel Extranet Access Client? Is this supported?(a) They cannot coexist, and it is not supported.(b) The two virtual adapters installed with each client will conflict with each other.(c) There is a utility on the new Cisco clients that will uninstall a Nortel client if found by the Cisco VPN Unity Client install program.(d) All other VPN Clients requ ire manual removal of the Nortel client or any other client.29. I am having problems with my VPN connection not already discussed.(a) Try isolating the problem by process of elimination.1. Is your Internet connection to the public Internet working properly?2. Do you have the most current version of the Contivity Extranet Access client?3. Have you recently installed any new software or hardware?4. Were any hardware or software changes made since your VPN connection was last working?5. Have you scanned your computer for viruses?(b) If you are still experiencing problems, try uninstalling/removing the following items.1. Disable your firewall, anti-virus software and any other maintenance or Security programs installed. Try to connect.2. Remove your router (Linksys, D-link, Cisco, Netgear, etc.) from your configuration.Connect your PC directly to your Internet connection.This is accomplished by connecting the cable coming out of your DSL/Cable modem, directly into your network c ard or USB connector.If successful, the problem might be your router's setup or firmware.Refer to your manufacturer's website or documentation for troubleshooting your router or contact the Vendor directly for support.You must upgrade your firmware.Please beware even though you might have just recently purchased your router, it might have been packaged with an older version of the software.3. Enable your router, firewall/internet security programs one at a time.Cable/DSL users: If you have a dial-up modem installed on your PC, try to test using a dialup connection. Either use dialup to an ISP and then use VPN.30. VPN Problems with Name Resolution using DNS services. Cause 1:A DNS server may not be configured for IPsec connections on the Contivity VPN Switch.Action 1:Validate that the Contivity VPN client has been configured with a DNS entry.For NT 4.0, open a Command Prompt and enter IPCONFIG /ALL.Verify that a DNS server entry is listed.For Windows 95, from the Start menu o n the taskbar, select Run and enter WINIPCFG.Select "Contivity VPN Adapter" from the pull down list of Adapters, then click More Info.Record the information displayed under DNS Server entry and verify it with the network administrator.Cause 2:The hostname being resolved has both a public and a private IP address. This is commonly referred to as a Split-Horizon DNS.Action 2:Open a Command Prompt and ping the host you are trying to reach with a fully-qualified hostname (for example, []).If you receive a response, verify that the IP address returned on the first line (for example, [207.78.33.329] is an IP address from the remote corporate network.If it is not, notify your network administrator that the internal hostname should be modified so that it is not the same as the external hostname.Cause 3:The retail release (a.k.a. "release 1") of Windows 95 contained a bug that prevented use of more than one DNS server. This problem was fixed in OS Release2.Action 3:If you are using a release of Windows earlier than Release 2 of Windows 95, then you need to upgrade.31. I am having problems mapping drives using the latest VPN client.(a) This is a known issue due to Microsoft that can occur when using cached credentials behind a NAT firewall.(b) The problem will occur for some users, but not others.(c) It can occur regardless of the VPN client you are using.(d) Some users may only experience this problem after upgrading to a new VPN client, but restoring the old client does not necessarily fix the problem.(e)You may try uninstalling the VPN Client and then reinstalling.

access point vs router

joi, 28 noiembrie 2013

Home Network How To - What Type Should I Use?

When I first started in computers, one of the most confusing things that I ran across was how to set up a home network. The differences between hubs, routers, Internet Connection Sharing (ICS) and cabling were a mystery to me. But after much trial and error and built-up experience I managed to figure a few things out and some of that information I will share with you now.There are two basic types of networks that I'm going to talk about in this article first being the infamous ICS or Internet Connection Sharing. ICS is usually implemented by connecting multiple computers through the hub to a single computer. Let's say we have three computers, Computer A, Computer B and Computer C. Computer A has enjoyed a high speed Internet connection and after a while, Computer B and C want to get in on the action! In order to implement ICS, we would have to connect all three computers to a hub.A hub is basically a switch that allows any computer hooked up to it to communicate with any other computer hooked up to the hub. So with all three computers hooked up to it, we would set the network up on the computers to use ICS. Computers B and C would be told that they're going to connect to the Internet through another computer that has a high-speed Internet connection. While Computer A would be configured to enjoy its high-speed connection as it did before.Configured like this, Computers B and C would enjoy a relatively fast connection to the Internet as would Computer A. The problem here starts when all three computers are accessing the Internet at the same time. Computers B and C would enjoy a relatively fast connection to the Internet while Computer A would suffer some moderate slowdowns because it not only has to handle its own traffic but the traffic of the other two computers as well. The user on Computer A is going to get quite upset if Computers B and C decide to download files at the same time. Because downloading a file is such a data intensi ve process, demanding large amounts of data be transferred from the Internet as fast as possible, Computers A may suffer some severe speed problems because of the demand being put on it from the other two computers.Unfortunately because of the fact that the hub does not have built-in firewall or any other such software that can protect the computers behind the hub Computers A must also be running Windows firewall in the background which provides an additional performance hit.So although the ICS is the cheapest way to go, it is definitely not the speediest way to go. In fact, to be honest, I would only follow this route if the users of Computers B and C had something against the user of Computer A and want to get even!The second type of setup that I'm going to talk about it is the router based set up. Nice thing about the router is that most routers are very intelligent. They have built-in firewalls, parental controls, can block sites or even allow users to have access to your network from the outside if they know the proper passwords and/or ports to connect through. No additional software is required that might add a performance hit and all three computers get configured the same way.To hook up or router you simply plug a cable from your Internet connection into the router then plug the three computers into the router as well. When you set up your computers you tell networking software that all three will computers have direct access to the Internet. There is some setup involved with router as is usual with any complicated piece of hardware but usually it is very painless and if you follow the instructions, quite easy!The nice thing about router set up is that once it is set, up all three computers enjoy the same speed advantages of being on a high-speed Internet. No one computer is impacted by the fact that someone else is downloading a file. In fact, all three can download a file at the same time and still enjoy impressive speed while doing so! Face it guys this is the network that you want to set up if your wife is on Computer A!Routers tend to be a little more expensive than hubs but the advantages of having them a part your network far outweigh any price difference. So if you must go with ICS, then do so with pride! But personally, I would recommend spending the extra money to go the "router route"!

access point vs router