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]

1. Some folks refer to APs as base stations. The role of an Access Point is to simply provide connectivity to wireless clients and put their signals onto the wired segment.

2. The purpose of a Bridge is to link wired segments to wired segments. The purpose of an AP I've defined. Some AP's have Bridge functionality (Cisco-Aironet APs certainly do).

3. Start out doing outdoor Bridging SLOWLY, get a few buildings linked and get your feet wet, don't just run out and buy for 20 buildings. There are challenges such as line of sight, and antenna mounting requirements. Yes I believe you can link that many buildings but please work with a Cisco account team to help you scale this properly.

[kevinbaum]

Hello Fred,

I need to set up a wireless network between two buildings. What would you recomend for equipment to use. The buildings are about 500 ft apart. I have tried the linksys WAP,s but lost signal half way between the buildings. Could you please advise me on a solution?

[fredn]

If the buildings are only 500 Ft apart, you could use the BR1300 series Bridge for 2.4 GHz or the BR1400 series Bridge using the less congested 5 GHz band.

Either product would work well.

Another option (if you can locate the AP indoors) and simply run the antenna cable outdoors might be to use a pair of AP1240's in Bridge mode.

Any of these three options would work fine, given the buildings are that close 500 Ft and I assume you have line of sight, the only advantage to using the AP1240 would be that you could use two sets of antennas (one on 2.4 GHz and one on 5 GHz) at each site, that way if you did encounter interference you could "software switch" between bands and you would have some redundancy should an antenna happen to get damaged or a cable cut.

[ragnar_anfinsen]

Hi Fred.

I have been tasked to find the recommended specs on building VoIP over WiFi in an outdoor city environment.

Do Cisco have any recommended guidelines for this kind of deployment?

What do you suggest the distances should be between AP's, including Mesh technology?

When doing sitesurvey, what RSSI threshold should we stay above to have a good VoIP link?

Best Regards

Ragnar Anfinsen

[fredn]

Please take a look at a previous post I've answered regarding outdoor VoIP applications. Distances between Mesh AP's were also defined in a previous post but to recap, distances from the ROOT AP (RAP) to Mesh APs (MAPS) is 1000-4000 Ft with distances between MAP to MAP around 500-1000 Ft (this is because the MAPs are lower to the ground) and client distance from MAP for 2.4 GHz access is roughly 300-500 Ft (further if external antenna is used on the client). RSSI thresholds while very important (you also need to look at how many "RF HOPS" the mesh is doing, as well as the backhaul mesh link and the 2.4 GHz client link.. (there is not one specific value), however there are design guides for indoor VoIP that may be helpful (see your Cisco account team for this) and other design help.

[sakthicisco]

hai fred

1)What is the diff between autonomous mode and unified network mode in 1310 series?

2)can a 1310 series in autonomous AP mode provide bridging,report IDS event,support 802.3af PoE,17dBi gain?

3)can a 3560 catalyst act as WLAN switch?

Thank u in advance..

[fredn]

When discussing the 1310 series outdoor Bridge product, the autonomous mode allows the AP to work as a Bridge (typically used to Bridge building to building traffic). In this mode a controller is not used. In the unified mode, the 1310 is no longer a Bridge but rather a rugged robust outdoor Access Point, in this mode the 1310 primarily services clients and is fully managed by the unified controller. It's really just two different modes (in autonomous it's a Bridge) in Unified it's a rugged AP.

Yes a 1310 in autonomous mode can provide Bridging, IDS events (and other non-Bridging functions only happen with the device is a unified AP). It does support 17 dBi antennas and rather then 802.3af, it supports a unique method of PoE that is better for outdoor usage, it injects power over the two RG-6 coaxial cables, this allows both Ethernet and power to travel to the 1310 and at the same time allow for proper grounding and lightning protection of same. A 3560 is not a WLAN switch per-se (you still need a controller) if you are running the 1310 in unified (LWAPP) mode.

[clark.ambrose]

Hello Fred:

Similar to a previous posting I have to recommend and implement a wireless connection between two buildings, however, these buildings are only about 200 feet apart and I have window or roof access in each building in a direct line of sight with no obstructions between them.

I believe I can install indoor APs in bridged mode, but I am not sure whether I will need an external antenna or not. The Aironet 1100 claims outdoor range of up to 225 feet at 36Mbps.

If I move up to the 1200 series, what size antenna would you recommend? The APs would likely be mounted within 1-2m of the antenna.

When I have been in the area I have detected no other wireless networks.

[fredn]

When Bridging across small distances such as 200 Ft many times simply placing the AP in the window may be all that's required. TRY IT and see.

Keep in mind some glass has "tinting" properties so signals going through the glass may be reduced by 3-5 dB or more depending on the number of panes of glass and if there is any conductive gas being used in the window and if the window is grounded.

The best antenna for putting in a window for this kind of a link would be a patch antenna since the patch antenna is flat and can be taped or secured to the window easily. I'd recommend a 6 dBi patch antenna Cisco AIR-ANT2460P-R if using 2.4 GHz. If using 5 GHz then use the AIR-ANT5170P-R.

For a complete list of antennas available, check out the antenna reference guide at this URL:

http://www.cisco.com/en/US/products/hw/wireless/ps469/products_data_sheet09186a008008883b.html

[advantexpix]

Hi Fred I was wondering if you could help. I have 4 x 1242 AP's setup as two seperate bridges. I'm looking to setup either load balancing between the two or just general link redundancy. what you suggest i do for this?

[khof]

Hi Fred,

I have two buildings connected with 2 x AP1231 in bridge mode. Now I have to trunk several VLANs between the bulding. Is this possible with this APs and do you have a link with an config example?

Thanx, Frank

[fredn]

The Access Points are running in Bridge mode at (layer 2) although it will pass the VLAN tags the Bridge will not perform any processing on same. You will need to handle this on the network side.

Take a look at the deployment guide at this URL, it should help you (BTW) when looking for information (check out the related product documentation) for example 1300 and 1400 Bridge product as all these devices run Cisco IOS so they make good reference material and sometimes address topics that perhaps the 1231 does not since the 1231 was not specifically designed for Bridging (that just happens to be a feature it supports).

See this URL for more..

http://www.cisco.com/en/US/products/hw/wireless/ps5279/products_technical_reference_chapter09186a00802a16cd.html#wp1010428

[fredn]

The Access Points are running in Bridge mode at (layer 2) although it will pass the VLAN tags the Bridge will not perform any processing on same. You will need to handle this on the network side.

Take a look at the deployment guide at this URL, it should help you (BTW) when looking for information (check out the related product documentation) for example 1300 and 1400 Bridge product as all these devices run Cisco IOS so they make good reference material and sometimes address topics that perhaps the 1231 does not since the 1231 was not specifically designed for Bridging (that just happens to be a feature it supports).

See this URL for more..

http://www.cisco.com/en/US/products/hw/wireless/ps5279/products_technical_reference_chapter09186a00802a16cd.html#wp1010428

[fredn]

You would really need to address this within the (network infrastructure) the Bridge is a layer 2 device so it can't manage different Bridge links for the purpose of load balancing. This is no different then a WLAN Bridge link and say a T-1 and trying to balance between same.

Suggest using PAgP for information on how to set this up on a Cisco Bridge link see the 1400 deployment guide at this URL.

http://www.cisco.com/en/US/products/hw/wireless/ps5279/products_technical_reference_chapter09186a00802a16cd.html

[fredn]

You would really need to address this within the (network infrastructure) the Bridge is a layer 2 device so it can't manage different Bridge links for the purpose of load balancing. This is no different then a WLAN Bridge link and say a T-1 and trying to balance between same.

Suggest using PAgP for information on how to set this up on a Cisco Bridge link see the 1400 deployment guide at this URL.

http://www.cisco.com/en/US/products/hw/wireless/ps5279/products_technical_reference_chapter09186a00802a16cd.html