Mesh Mobility

[muratg7777]

Hi;

We have 5508 Controller and 1242AG  Aps.

I want to use 1242 APs as RAP and MAP mode. The problem is MAP will be on a mobile truck.  If 1242 MAP are on the coverage of RAP does the connection lost when the mobility happens?? or can I see packet lost when the client is connected?

I have tried to use 1310 AP with Autonomous mode but the connection is getting lost when the mobility hapens.

[Nicolas Darchis · Accepted solution]

Hi Murat,

MAPs are not supposed to be mobile. If you want to have an infrastructure providing wireless to trucks, the solution to use is fixed MAPs and RAPs. The AP on the trucks will have to be a IOS WGB. This is the AP mode where the AP really acts as clients and takes roaming decisions.

A MAP will take an awful lot of time to renegotiate connectivity to RAPs.

HTH,

Nicolas

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[muratg7777]

Hi Nicolas;

Thanks for the answer. So The WGB will be in autonomous mode and it will connect to lwapp ap as client.

On the Ethernet port of WBG, I will connect LWAPP AP and it will register to WLC.

Am I right?

http://www.cisco.com/en/US/products/ps6366/products_configuration_example09186a0080905cea.shtml

There is a good example of WGB. On the Network topology, exclude the switch, for it will be a LWAPP AP.

If I remember right. I can also configure "mobile station" under dot11radio interface when it is in WGB mode

[Nicolas Darchis]

Hi Murat,

you're all correct but why do you want to place an LWAPP access point behind the WGB ?

Nicolas

[muratg7777]

Hi Nicolas;

Think a port. There are 2 big poles and we have access points mounted on the poles. That's good for the ports road. They use hand terminals.

But our client also wants to use hand terminals on the ships too. I have located a new access point to the pole with the directional antenna and tested the coverage. It was not good. The poles are at the edge of the road.

So the plan is put new wireless devices on the crane which is the only way to locate new access points after poles.

We can not connect cable to AP, because crane is a mobile vehicle.

So I will connect as WGB mode to lwapp AP. On the WGB; the wireless Lwapp ap will be for ships and roaming for hand terminals.

I am thinking to use 2506 Antenna.

[Nicolas Darchis]

Hi Murat,

I'm still not sure I'm getting it but the point I was trying to raise is the following :

for fast roaming and mobility, we talk about the clients roaming between different APs.

An Lwapp AP that would be on a moving vehicle would face a major problem : every x seconds it would be disconnected from the controller and would have to search again for it. This is why having Mesh APs on moving devices is a bad idea because they take too much time to re-negotiate a link to a RAP.

Now your setup of a LAP behind a WGB, I have to admit I never saw it so I can't comment on it much. The goal is to have the LAP never lose connectivity to the network. If the LAP just discovers a WLC on its ethernet port and stays connected, it won't see any difference I guess. But that means the WGB should always keep the uplink active (and never go into a no-coverage zone). This is up for you to determine if feasible or not.

As tac engineer, what I often saw in those situation were devices like the 3270 MAR that was having 2 radios, one for uplink connectivity (WGB) and one for local client access.

Hope this helps,

Nicolas

[muratg7777]

If on WGB mode the ap will connect as client. It must work.

The hand terminals can roam without connection lost.  I will demonstrate it and tell you what happened.

On ther other side, user guide says:

Configuring a Workgroup Bridge for Roaming
If your workgroup bridge is mobile, you can configure it to scan for a better radio connection to a parent
access point or bridge. Use this command to configure the workgroup bridge as a mobile station:
BR(config)# mobile station
When you enable this setting, the workgroup bridge scans for a new parent association when it
encounters a poor Received Signal Strength Indicator (RSSI), excessive radio interference, or a high
frame-loss percentage. Using these criteria, a workgroup bridge configured as a mobile station searches
for a new parent association and roams to a new parent before it loses its current association. When the
mobile station setting is disabled (the default setting) the workgroup bridge does not search for a new
association until it loses its current association.

Also the WLC will make the roaming decisions.

[Nicolas Darchis]

Correct for the WGB Murat.

But my concern was the LAP that you connect on the WGB wired side. That LAP has no idea about being behind a wireless link. It just sends packets to the WLC.

So if ever for some reason the WGB lacks connectivity for few seconds, the LAP will go in LWAPP/CAPWAP discovery mode again and that will harm your network.

That was just my point.

Nicolas

[muratg7777]

Thanks for the clear answers Nicolas.

One last question. Does the 1242, 1252 and 1310 LAP has High-Speed roaming? Or what is the maximum speed for clients?

I only find information about 1500 series.

1522 LAPs are most suitable for this topology?  The WBG will be 1310 or 1252 AP

Client Roaming

High-speed roaming of Cisco Compatible Extension (CX), version 4 (v4) clients is supported at speeds

up to 70 mph in outdoor mesh deployments of AP1522s and AP1524s. An example application might be

maintaining communication with a terminal in an emergency vehicle as it moves within a mesh public

network.

Three Cisco CX v4 Layer 2 client roaming enhancements are supported:

• Access point assisted roaming—This feature helps clients save scanning time. When a Cisco CX

v4 client associates to an access point, it sends an information packet to the new access point listing

the characteristics of its previous access point. Roaming time decreases when the client recognizes

and uses an access point list built by compiling all previous access points to which each client was

associated and sent (unicast) to the client immediately after association. The access point list

contains the channels, BSSIDs of neighbor access points that support the client’s current SSID(s),

and time elapsed since disassociation.

• Enhanced neighbor list—This feature focuses on improving a Cisco CX v4 client’s roam

experience and network edge performance, especially when servicing voice applications. The access

point provides its associated client information about its neighbors using a neighbor-list update

unicast message.

• Roam reason report—This feature enables Cisco CX v4 clients to report the reason why they

roamed to a new access point. It also allows network administrators to build and monitor a roam

history.

[Nicolas Darchis]

The documents say what has been tested. I suspect that no specific speed was tested with RAPs on other platforms but I strongly think the speed is the same.

The important is the roaming mechanism and the lwapp/capwapp software is the same between APs.

What is important for roaming speed is the client. WGB 1242 gave very good results out of my experience.

I saw 1242s deployed on a metro train running a 80km/h. That's all I can comment on :-)

The problem wit h the speed is the small amount of time you spend under each AP. So this is also related to the coverage.

In the case I mentioned, there were directionnal antennas in the metro tunnels, so coverage was great. Meaning there was not that many roaming compared to the speed of the metro.

If you want an official word with guarantee, Cisco account teams are the best placed for that as they would study your deployment and recommend the best way to go. Here is just a best effort forum :-)

Nicolas

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[muratg7777]

Thanks for the replies Nicolas

[muratg7777]

Hi Nicolas;

It didn't work. I succefully connected to workgroup bridge and it roams without any packet loss. I tested with my notebook but when I connect LAP, it recieved ip from dhcp but it did not registered to WLC. I tested to ping WLC from LAP it was succesfull.  Maybe lwapp packets are getting timeout

Next I will configure 1 AP (1242AG) for workgroup bridge (5ghz) and 2.4 for clients.

[Nicolas Darchis]

Hi Murat,

something must be missing. I would suggest to insist a bit with the lwapp ap. Did you check the lwapp ap console output ? it generally prints why it's not finding a WLC (if it received an option 43, etc ...).

Dont' rely on subnet broadcast discovery for WLC but advertise it clearly in option 43 or DNS.

Regards,

Nicolas

[muratg7777]

Yes I did.

I tested with 2 1242G LAP.

First ap was in factory default. I connected to WB and the LAP recieved ip from DHCP. The image upgrade was unsuccesfull.

I pointed to " lwapp ap controler ip address ...." but still did not registered to WLC

I registered the second LAP to WLC and did an image upgrade and then I connected to WB. The second LAP did recieved IP from dhcp but it was releasing it's ip address and getting ip address again and again so packet lost happened on it. Bu I don' see packet lost when I connected my notebok to WB.

sh ip int b   output was dot11radio0 UP but I couldn't see that LAP on WLC.

It finds the WLC on cable network without problem. We have 45 LAP working on the site. Is dhcp option would be problem cos we don't use it. Windows Server 2003 is the dhcp server.

But if the LAP can not find WLC the " lwapp ap controler ip address ...." should work.