ASK THE EXPERT - OUTDOOR WIRELESS

[ciscomoderator]

Welcome to the Cisco Networking Professionals Ask the Expert conversation. This is an opportunity to get an update on Outdoor Wireless with Cisco expert Fred Niehaus. Fred Niehaus is a technical marketing engineer for the Wireless Networking Business Unit at Cisco Systems, Inc. He has extensive customer contact and is responsible for developing and marketing enterprise class wireless solutions using Cisco Aironet and Airespace Series Wireless LAN products.

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. Our moderators will post many of the unanswered questions in other discussion forums shortly after the event. This event lasts through April 20, 2007. Visit this forum often to view responses to your questions and the questions of other community members.

[fredn]

You can use Cisco WCS for more information on this product check out the URL here:

http://www.cisco.com/en/US/products/ps6305/index.html

[fredn]

There are really two different operating systems that you are calling out here stand alone IOS (autonomous) and LWAPP (unified)mode.

The reason there are two different operating systems is because they serve different but similiar purposes.. mainly revolving around "features".

The (unified system) requires a controller and it has some features like rogue AP detection and location based services) that are not really supported with autonomous (stand alone IOS systems).

The Stand alone IOS (autonomous) has the advantage of not requiring a controller and is better for some smaller verticals where perhaps you are not using as many APs and therefore don't need a controller (such as a point to point Bridge link or small office.

For managing (unified LWAPP systems) I'd suggest using WCS see this URL:

http://www.cisco.com/en/US/products/ps6305/

For larger IOS (autonomous) based systems, the management utility is WLSE see this URL:

http://www.cisco.com/en/US/products/sw/cscowork/ps3915/index.html

[fredn]

1200 series APs that contain the 802.11g radio (not the older .11b radio) can be upgraded simply by loading new firmware to work in a unified (LWAPP) mode. If the 1200 series AP has a 5 GHz radio (it must also be one of the newer radios (white serpentine stripe or support external antenna connectors). The older black stripe (serpentine) 5 GHz radio and/or the older 802.11b only radio is not supported within the unified (LWAPP) code.

Given your unit has an 802.11g radio I see no issues or problem with upgrading it to unified.

[fredn]

Yes you can upgrade your AIR-AP1231G-A-K9 autonomous AP to LWAPP. Any 1200 series AP with a .11g radio can support LWAPP.

As a side note, the older 1200 series AP with the .11b only radio (350 series) can also be upgraded to LWAPP but before you do this, you must remove the old .11b radio and upgrad to a .11g radio first before going to the LWAPP image.

[mwhalen]

Fred,

My company is being asked to provide outdoor public and private wireless coverage at an increasing rate. One of the biggest problems with the 1500 mesh solution is in the site survey and cost estimates. Can the 1500 AP be used in a site survey mode? Most customers want to know a fixed cost when delpoying any system and with wireless, it is difficult to be accurate because of field conditions that always appear. If the project is underbid because some unknown condition exists, then the costs usually have to be absorbed by the installing company. Do you know of any way to mitigate these problems and provide more accurate deployment estimates? Thanks

[fredn]

Well generally (assuming you have line of sight) the AP placement distance is as follows...

Root AP to Mesh AP 1000-4000 Ft

Mesh AP to Mesh AP 500-1000 Ft

Client to Mesh AP 300-500 Ft

While you can do some surveys with the 1500 (client connectivity) performing a backhaul survey can be done using WCS or simply looking at the link from the controller.

As far as estimating number of APs, there are third party RF prediction tools from folks like www.edx.com and www.airmagnet.com

Also, Cisco has training for customers who become a Cisco Advanced Technology Partner.

[jllugar]

Hi Fred,

I have a new location coming online and it is close to a location that has a fiber connection back to our central hub. Wireless is being considered to do this...however, is that recommeded for VOIP? We have two call managers at the central office so it will have to travel from the new location over the wireless and through the fiber back to the central location... Is this feasible?

Thanks!

[fredn]

Is outdoor wireless links recommended for VOIP is I suppose the real question here. Yes I think it is provided you understand the caveots with deploying same. Given WiFi is an unlicensed technology, and anyone may use the frequencies, it is susceptible to interference. When deploying wireless indoors (you pretty much own the RF environment) as signals rarely travel far outside your "windows" and the amount of interference penetrating your building is also small.

When doing an outdoor link, the antenna is outside (free to pick up signals from other sources) and if those sources are powerful (say the guy next door is running a Wireless ISP on those channels, or perhaps a nearby person with a "slingbox" type device is sharing his cable TV with his friend down the street... in those specific cases the quality of your connection could be effected regardless if QoS or CAC is enabled on the device.

Although the chances are real good that you would not encounter interference and that such a link would work well, perhaps for years without an interference issue.

I believe that if you are using outdoor VOIP for emergency traffic, or if this link must remain up (at all times) then perhaps it is better to consider Wireless as a great "backup" link, or I would consider adding redundancy to the system with another wireless link on a different channel or perhaps have a fail-over to a more costly alternative such as a wired (subscriber based) system.

I would be hesitant to recommend an outdoor WiFi link as the main conduit for emergency VOIP traffic without a fall-back technology, such as another wireless backup link or wired fail-over.

[abuera]

Hi Frank,

My customer needs an outdoor wireless solution for a 2km Funicular environment.

I was thinking of a 1300 Aironet solution with an AP mode for the fixed installed equipments along the railway and a workgroup mode for the in-vehicle equipments that would be connected to the CCTV cameras.

What do you recommend?

Thank you in advance.

[fredn]

1300 AP, or a 1500 Mesh AP, (or even a 1240 in a NEMA enclosure) are all "fair game" for such a deployment (which one to use depends on the size and logistics of the deployment I suppose). 1300s would work fine and you could use a 1240 in the vehicle (using WGB mode). CCTV cameras should be the "smart kind" meaning they should be Ethernet friendly and consume bandwidth needlessly like analog cameras typically do.

[azazello_cisco]

Hi Fred,

I've got a general question about outdoor wireless. As you might know, some small cities in the USA are almost totally covered with wireless. How is that achieved? I mean, are there any special equipment or special protocols, not a,b or g? Please tell me more about it and if possible provide with some useful links.

Thank you very much in advance

[fredn]

There are many ways to "blanket a city" with wireless, a very common approach is to use the Cisco 1500 outdoor mesh solution at this URL

http://www.cisco.com/en/US/netsol/ns621/networking_solutions_package.html for an overview, I'd recommend then watching the Dayton Ohio deployment video.

The way it is typically done is like this....

A RAP (Root Access Point) is placed at a good location, say on top of a large building that overlooks an area of the city or town.

This RAP unit has a wired connection back to the controller and establishes a wireless link to another AP (referred to as a MAP or "Mesh Access Point") using 5 GHz or if public safety perhaps 4.9 GHz.

These MAP devices are located in the area of the users typically atop street lights (using the photocell pass through adapter on the light) to attain power for the MAP. MAPs then link to other MAPs and "find their way through the mesh" to a RAP that puts them back on the network.

The network is then scaled out by using many RAPs and MAPs. Mostly this is done with 802.11a/b/g type radios.

However, when there is a requirement for non 802.11a/b/g wireless links then in some cases a Cisco CTDP (Certified Technology Developer Partner) is used, for example, Redline Communications http://www.redlinecommunications.com/ may be a good fit when there is a requirement for say a WiMax link.

[azazello_cisco]

Thanks Fred, your reply was extremely useful for me. I have some more questions regarding this topic:

1. The a,b and g standards have a limitation of 100m, I guess that means that i have to deploy MAP-s in every 100m. How real is to cover whole city with that? Maybe Aironet 1500 can reach distances more than 100m?

2. What's the maximum(recommended) number of MAPs I can deploy between two neighboring RAPs?

3. Will this wireless mesh interference with possibly existing wireless signals penetrating out of the nearest buildings(indoor Wireless LANs) placed in radius of 100meters?

4. Will this wireless mesh reach any offices in neighboring buildings?

Thank you once more,

Vitali

[fredn]

Well the issue of client distance has to do with the client. Most clients (laptops) have an antenna that is buried inside the laptop and it is of very little gain. That is the real limiting factor here in distances ending up approx 300-500 Ft. If your client has an external antenna (say mounted on top of a vehicle) then range can much further.

As far as covering an entire city, although this can be done, generally folks start out covering "key areas" and then expand to other areas and the need for coverage in those areas increase. WiFi uses a very low power typically around 100-500 mW (a typical "walkie talkie" is 5000 mW (or 5 Watts) the reason WiFi power is so low is to permit it's wide spread use without causing severe interference to others. It's that requirement that drives the need for additional units, and why each unit creates a "small" cell.

Maximum number of MAPs is really a factor of the radio bandwidth available, while you can create very high dense deployments of MAPs you'll want to add additional RAPs to properly manage the flow of data.

Take a look at this URL that specifically talks about the 1500 (and there is an archived 1500 mesh discussion).

http://www.cisco.com/en/US/products/ps6548/

There is also a Cisco Mesh deployment guide that should also help answer many of these questions.

http://www.cisco.com/en/US/products/ps6548/products_technical_reference_chapter09186a008062bd41.html

Wireless mesh can reach nearby offices if those offices have CPE (customer Premisis Equipment devices) meaning wireless Bridges or other devices. Usually a laptop within a building has too weak of a signal to hit the mesh unless the operator happens to be near a window.

[sakthicisco]

Hi Fred,

I hav got 3 questions to ask u.I need guidance in outdoor wireless networking.

my project has both multiple base station and pt to pt base stations

1)Does Access point is similar to base station?

2)How can we diffrentiate Access point from Bridge function?

3)Can i use Aironet 1300 series,interconnecting 20 buildings in an area A1 which includes pt to pt and multi pt bridiging?

Awaiting for ur reply