Newbie: Roaming between AP's?

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Newbie: Roaming between AP's? Paul Adams 5/22/12 12:46 PM
 
Hi,
 
Firstly - the goals of your project are wonderful. Well done and good luck.  I'm in Canada and the forest fire situation can lead to some communications issues.  A project such as yours would be very useful.
 
 
Secondly, I'm looking for a solution to provide VoIP over WiFi that can provide fast handover (without dropping live VoIP calls) and use 'cheap' cell phones, (Nokia / Android  /etc).
 
I appreciate this may not be what Serval was intended for, but can Serval support this kind of environment - roaming between access points and maintaining calls? What would it require - Serval on AP's plus Serval on the devices? Is there a flavour of Serval for OpenWRT for AP's?
 
Any advice welcome...
 
 
I've had some good results with both SMESH and WING open source mesh networks.  I'm currently using Nokia E63 devices with the built-in SIP client plus extended batterys on a SMESH network at work.  It works well most of the time, the odd glitch.
 
Thanks for your time...
 
Regards
 
Paul Adams
 
Re: [serval-project-dev] Newbie: Roaming between AP's? Jeremy Lakeman 5/22/12 3:37 PM
Right now we're writing our own voice and data transfer network
protocols for talking between phones that are wandering around the
same adhoc mesh network.
We also have a student looking at building a gateway between our
protocol and SIP for talking to traditional VOIP systems. At this
point, provided the gateway is on a fixed network, I believe roaming
around different access points while maintaining a call to the outside
world should be possible.
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Re: [serval-project-dev] Newbie: Roaming between AP's? Paul Gardner-Stephen 5/22/12 3:49 PM
Hello Paul,

On Wed, May 23, 2012 at 5:16 AM, Paul Adams <pad...@pchtg.ca> wrote:
>
> Hi,
>
> Firstly - the goals of your project are wonderful. Well done and good luck.
> I'm in Canada and the forest fire situation can lead to some communications
> issues.  A project such as yours would be very useful.

Thank you -- we hope that it will indeed be useful in such situations.

> Secondly, I'm looking for a solution to provide VoIP over WiFi that can
> provide fast handover (without dropping live VoIP calls) and use 'cheap'
> cell phones, (Nokia / Android  /etc).
>
> I appreciate this may not be what Serval was intended for, but can Serval
> support this kind of environment - roaming between access points and
> maintaining calls?

This is something that we intend to support, but haven't quite got there.
Having said that, once we have the 0.09 release out in a few weeks,
all the groundwork will be there to support this.

The caveat is that the trick that we intend to use for doing this has
yet to be tested, and we are not yet sure which handsets it will work
on.  The trick is to put all the phones in access point mode, and then
enable monitor mode between them (perhaps using libpcap on systems
that support it).  They will then be able to hear each other's
broadcast packets (even if SSIDs and ESSID's don't match).

If you would like to try some experiments on this front for us on
Android, Nokia S60 phones and/or OpenWRT hardware, that would be very
useful.

> What would it require - Serval on AP's plus Serval on the devices?

That would be ideal.  We have plans to setup a similar deployment with
Airstream here in Adelaide once we get the necessary code complete.

>  Is there a flavour of Serval for OpenWRT for AP's?

We haven't built it for OpenWRT devices for a while, but it should
work without difficulty.
The ability to work on fairly arbitrary hardware has been a key focus
of the recent development work.

> Any advice welcome...

One other plan we have that may be of interest to you is to use IOIO
boards to attach HopeRF ISM 915MHz band UHF radios to the phones, and
allow much longer range between phones.  We are also exploring getting
some custom made Android phones with an Arduino built into the phone,
and that can power and house the HopeRF internally, so that there are
no dangly bits.  But we need to raise about US$150k to do that.  But
once we do, we will be able to support hundreds to thousands of metres
between phones, which is really game-changing for mesh telephony.

> I've had some good results with both SMESH and WING open source mesh
> networks.  I'm currently using Nokia E63 devices with the built-in SIP
> client plus extended batterys on a SMESH network at work.  It works well
> most of the time, the odd glitch.

Most interesting.

Paul.

> Thanks for your time...
>
> Regards
>
> Paul Adams
>
>
Re: [serval-project-dev] Newbie: Roaming between AP's? Paul Adams 5/22/12 5:49 PM
 
Thanks Paul,
 
I am happy to test what I can (time permitting).  I have a range of devices...
 
I'm running SMESH on Linksys WRT54GL devices, the modified Kernel version of OpenWRT.  If you are interested - www.pauladamsit.com - see the "cheap voice wifi" link on the left... It's been running for over a year now providing voice services from an Asterisk server, which is also connected to the main company Panasonic PBX.  The glitch seems to be if you leave the wifi area and then return, it does not re-register with the Asterisk server.  A reboot of the phone cures that.  I'm getting about 14 hours from an extended E63 battery.
 
 
As a recommendation for an AP, you maybe interested in the Buffalo WZR-HP-AG300H device.  An impressive device for the money - 680Mhz processor, 128mb ram, 32mb flash, dual radios (802.11AN and 802.11BGN).  I'm running OpenWRT with OpenVPN on 5 of these and it works very well.  I am also pushing VoIP (SIP and H323) over these links.  They work better then the Sonicwall devices we had before...
 
 
The long range radio concept is a good idea - but I wonder if that would raise the price of your cheap Android phones to a point where it's not an option for poorer areas?  However - it's a great idea for disaster zones...
 
 
I really like the idea of being part of some sort of volunteer group (kind of like volunteer firefighters) that have a stash of AP's  / attennas / phones - all configured and ready to go.  That group could be called in an emergency to provide voice / data services, setup comms, hand out phones, etc...
 
I know - I get excited...  Baby steps...  :-)
 
 
Regards
 
Paul Adams
Re: [serval-project-dev] Newbie: Roaming between AP's? Cathy Ewald 5/22/12 6:41 PM

Hi Paul
I come from Brisbane Australia and we experienced serious floods in 2011. I would like to be part of the type of group you describe here! And parts of Australia are prone to fires too.
Cheers
Cathy

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