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ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Welcome to the Cisco Networking Professionals Ask the Expert conversation. This is an opportunity to discuss Metropolitan Mobile Networks with Cisco expert David Yuan. David is a Product Manager with the Product and Technology Marketing Organization –Wireless Mobility Group at Cisco Systems, Inc. David has 22 years of experience in the telecommunications and networking industry. Remember to use the rating system to let David know if you have received an adequate response.

David 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 January 30. Visit this forum often to view responses to your questions and the questions of other community members.

20 REPLIES
Silver

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi David,

How do we deal with wireless security in an outdoor environment?

Thanks

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

There are a few methods depending on the customer preference, VPN is the most popular way for most users.

David

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi David

I have a general question. What type of products are ideal for MMN deployment?

Thanks.

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

For MMN outdoor wireless deployment, the Cisco wireless bridge ( BR1400, BR350 ) would be ideal. BR1400 would be used for backhaul, point to point or point to multi-point connectivity. BR350 would be used for bridging and also to associate with clients. AP1200 could also be used, but the distance you get would be shorter than a BR350. We also have the 3220 Mobile Access Router for mobile networks deployment in moving vehicles.

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

David,

I noticed that you said range for the BR350 will be longer than the ap1200. Why is that? Aren't they both 100 mW radio's. Reason I am asking is I have AP352's deployed, and with EOL on those, I am switching to AP1200's. Would I be better of with BR350's?

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi,

There is actually another factor besides radio power and hi-gain antennas. The reason BR350 can communicate farther is because traditional APs have to adhere to the IEEE spec of transmission distance limited to within 1 mile. Therefore, the AP 'timing' parameter for a round trip packet transmission delay is set at a fixed value to allow for up to one mile. Unlike APs, the BR350 bridge has an optional setting (called Bridge Spacing) that will allow the bridge to compensate for distances above 1 mile.

David

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Really??!!

There is nothing oabout that in the liutearture, and we are using AP350's and 1200's in a WISP envirnment with some of the connections out at 6 miles, They work ok, but we do see high CRC errors

occasionally. I wonder if this explains it...

Is there any way to tune that parameter?

Scott

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Scott,

For high CRC errors, unfortunately there is no special parameters to tune this. This could well be due to some interference. I would suggest to try align your antennas to point at different angle or direction, if it is possible to do.

David

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

David,

We actually suspect multi-pathing and hidden node issues. I was just concerned with your timing statements. If you want to know more about our set-up, we welcome sharing our experience with y'all. We have 16 Cisco 350/1200's deployed on a total of 7 towers (soon to be 10) and have ranges from 0.1 to 6 miles off each.

Scott

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi Scott,

Sure, I would be interested to learn more about your set up. Could you send me your contact info to my email address, dyuan@cisco.com. We can have a chat early next week, as I am tied up with meetings most of this week.

Thanks,

David

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi david

we are cisco partner and support some WISPs, we are useing already br350 (br1400 are not allowed in austria) what kind of end (user) device would you recommend? WGB 350. we are using wgb 350 with leap. (about 400!) but we are not able to mange them (wlse does only support wgb as clients). and what would you use to monitore the wirless site also wlse?

Are there any design recommendation from cisco how to build a WISP for a really BIG area. we have many issue to manage and controll the clients (P2P and so on)

regards Bernhard

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi Bernhard-

For end user device, this would really depend on their applications. Some end users prefer to use PDA, due to PDAs are lighter than laptops. Government employees or police in vehicles would use Mobile Access Router and bridge to connect to their IP devices. You are correct that the WLSE currently only support the WGB as a client. We may in the future look at supporting it as a WGB, depending on business case and development priorities. For monitoring outdoor wireless site for bridges and APs, we would still consider using WLSE as our wireless management tool.

On the design recommendation, it is a challenge to provide a wide area blanket coverage, inch by inch.

This is due to limitations that come with the Wi-Fi technology such as distance coverage, line of sight and radio interference. Our suggetions is to place

local outdoor hotspots at strategic locations such as along the central business districts, main streets areas etc.

Hope this helps.

David

Silver

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi David,

Is it possible to use a very high gain antenna with amplifier to get the maximum distance coverage?

Regards

Tom

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi Tom,

Yes, it is possible to use, as long as it meets the FCC compliance regulation spec. for EIRP FCC-36 dBm, and for ETSI-20dBm.

cheers,

David

Bronze

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi David,

Is it possible to get wireless coverage for an entire city?

Thanks

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi - It would be a challenge to get wireless coverage for an entire city, especially if it is a major metropolitan city. This is due to the distance limitations on the radio broadcast range for 802.11. There are also factors with line of sight, and interference.

David

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

David

What are some of the antennas being used for a Metropolitan Mobile Networks deployment?

Thank you!

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

There are a few types of antennas that can be used for a Metropolitan Mobile Network deployment. Depending on the application and usage, one can use an omni antenna for point to point or point to multipoint connectivity.

For line of sight directional connectivity, you can use a Yagi antenna. For connectivity over a farther distance, one can use a dish type antenna.

David

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi David,

Thank you for answering my previous question. One last one - When would you use a BR1400 vs a BR350?

Thanks

New Member

Re: ASK THE EXPERT- METROPOLITAN MOBILE NETWORKS

Hi - The BR1400 is normally used for backhaul connectivity, since it is operating on the 802.11a frequency band and has a much higher data rate (54Mbps) than the BR350. BR350 operating on 802.11b, 2.4GHz, can also be used for backhaul, and point to point, or point to multi-point connectivy.

BR350 is also used for connectivity to clients over a longer distance.

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