ASK THE EXPERTS - Update on 802.11n with Fred Niehaus

[ciscomoderator]

Welcome to the Cisco Support Community Ask the Expert conversation. This is an opportunity to get an update on 802.11n with Cisco expert Fred Niehaus. Fred is a Technical Marketing Engineer for the Wireless Networking Business Unit at Cisco, where he is responsible for developing and marketing enterprise wireless solutions using Cisco Aironet and Airespace wireless LAN products. In addition to his participation in major deployments, Fred has served as technical editor for several Cisco Press books including the "Cisco 802.11 Wireless Networking Reference Guide" and "The Business Case for Enterprise-Class Wireless LANs." Prior to joining Cisco with the acquisition of Aironet, Fred was a support engineer for Telxon Corporation, supporting some of the very first wireless implementations for major corporate customers. Fred has been in the data communications and networking industry for more than 20 years and holds a Radio Amateur (Ham) License "N8CPI."

Remember to use the rating system to let  Fred know if you have received an adequate response.

Fred might not be able to answer each question due to the volume expected during this event. Remember that you can continue the conversation on the Other Mobility Subjects discussion forum shortly after the event. This event lasts through March 25, 2011. Visit this forum often to view responses to your questions and the questions of other community members.

[Stephen Rodriguez]

Hi Fred,

    I was wondering if you could go over the beamforming or client link features of the "N" access points, and how much of a increase could be seen by using this feature.

As a secondary question, when will the BLD be integrated into the 3500 AP?

Cheers,

Steve

[fredn]

Beamforming is a method by which the Cisco 802.11n Access Point can focus the RF energy directly at the client.

Given the Access Point has three antennas per band, when a client is received at the Access Point, the Access Point can determine where the client is and direct the energy at the client.  Client link is not designed to increase the overall range but rather, client link is designed to enhanced the client experience by pulling the client out of the "dead spots" and/or take an existing client and make the signal better in an effort to raise the signal to noise so the client can negotiate a higher data rate.  For more on beamforming (Cisco ClientLink) see the following URL.

http://www.cisco.com/en/US/prod/collateral/wireless/ps5678/ps10092/white_paper_c11-516389.html

Can you rephrase the second part of your question? Not sure I understand what you are asking there.

[Stephen Rodriguez]

Fred,

     BLD = Blue Laser of Death, that nice addon to the 3500 that shoots the problems right out of your network!  Was a referrence to a youtube video, that I can't find the link to at the moment

[fredn]

ROFL.. Ok I read BLD and thought "build" as in version number? ..

I suppose you'd have to run that by Jameson Blandford - I believe he is one of our "youtube" stars..

I'll let him know we need more BLD videos... lol

Fred

[George Stefanick]

Hi Fred,

Will cisco support 3x3:3 and or 4x4:4 if so when will the access points be out?

[fredn]

So there are two parts of this question, the latter part I cannot address as it is a future question.  Cisco does not comment on products that have not been released or on the strategy of next generation products.

That said, Cisco was first to market with an 802.11n Access Point and well (we didn't all go on vacation after we did that)

So let's talk a little about spatial streams in general and how it relates to what customers are doing today.

The Cisco 1040, 1140, 1250, 1260 and 3500 Series Access Points are all two spatial streams (2SS).

As of the time of this writing, a critical mass of 3SS and 4SS compatible clients have yet to be deployed, and the vast majority of WiFi clients that will be deployed over the next 18 months will be 1SS and 2SS clients.

The higher SS clients are likely only show up in some higher end notebooks -- Why? well it is a given that smartphones and tablets are likely to continue to be 1SS and in some rare cases 2SS.

This is because additional radios used in this technology consume battery life, add to the physical size of the device and increase the cost. Also many devices leverage the same single antenna for cellular as well as WiFi.  Therefore, it is my opinion that 3SS Access Points provide little if any performance benefit for smartphones or tablets in the enterprise today, and any real throughput gain is likely to occur with high end notebooks in close proximity to the Access Point and those are rolling out very slowly and we are monitoring this.

Now we get to my favorite part of this..  I get to ask myself a question and then answer it..

So Fred are you saying that there is no value in 3SS and 4SS?

Of course not, 3SS performs similar to 2SS beyond a short distance, and with any multi-SS product RF interference must be addressed to capture the performance benefits of higher SS Access Points. Actual throughput in any WiFi environment is highly dependent on the presence of interferers and obstacles.

Without the ability to mitigate the impact of interference, 3SS solutions will "downshift" to 2SS of 1SS and lose all the performance benefits anyway IMHO.

I don't want to sound like a commercial, but you really do need Cisco cleanair technology in the AP and Cisco innovations deliver more and will go beyond the simple 3SS aspects of the 802.11n standard.

IMHO it's more about CleanAir, good RF system design, and what we put into the AP with regard to performance "in the environment" and not what is on some spec sheet today.

For more on Cisco CleanAir see the following URL http://www.cisco.com/en/US/netsol/ns1070/index.html

Fred

[Leo Laohoo]

Nice post Fred.  Thanks. 

[simpsonja]

Hi Fred

my question should be simple but i cant find an answer to it anywhere. How many ports can i include in a CatOS command?

Example:
set port disable x/x, x/x, x/x......

or

set port name x/x, x/x, x/x...... Available

I have a 6513 full of 6148x2 blades in it. So needless to say i have hundreds of ports to configure.

Thanks for your help

[fredn]

I believe you can do them in ranges like for module 1 ports 2 through 48

set port disable 1/2-48

I know it won't span modules, but it should stretch over ports on a module, and you can add more ranges...

set port disable 1/2-48, 2/2-48, 3/2-48

If possible please keep questions related to my core expertise WLAN and 802.11n standards as I'd hate to steer you wrong on anything.

Regards,

Fred

[uhudson_z]

Hello,

It apears that the daylight savings time functions for cisco phones are spotty and unreliable.

One phone will accept the settings, another phone with the exact same profile pushed to it ( so both are exactly identical ) will not.

No time server, date, or time related settings will ever make the cisco 962 get the correct time.

How to wrench / force the time to be correct?

It will noit accept manual changes, nor those added through direct configuration file.

The firmware is updated, and the phone is working ok otherwise.

How to correct this pathetic and unwated flaw in your phone?

Thanks

( I know this discussion has to do with wifi protocols, but that is only a fraction as usefull as the real issue such as this )

[fredn]

Thank you for the comment on the phones.

If the phone does indeed have this problem, and assuming you have a support contract, the best course of action would be to open a trouble ticket on this.

Unfortunately, the phones are outside of my core expertise.

A trouble report on this can be opened by contacting Cisco on the phone or at the following URL

http://tools.cisco.com/ServiceRequestTool/create/launch.do

Regards,

Fred

[tonydanle]

Hi Fred,

     I would to ask you why can't my linksys e3000 router portforward 3784 for ventrilo. I tried to search up websites of infomation to help me portforward but it still won't work. I also check if my port is open but it isn't. May you please help me on this problem? thank you

[fredn]

Thank you for the question on the LInksys products, unfortunately I've not worked with that particular product.

Best course of action would be to open a trouble case with Linksys and you can do so at the following URL

http://homesupport.cisco.com/en-us/wireless/linksys

Regards,

Fred

[twegmans]

Hi Fred,

Any idea when the new appliance based Wireless Control System platform will be released?

Thanks