[asterisk-users] Wi-SIP & 802.11f - Inter Access Point Protocol HANDOFF

[Duncan Turnbull]

Its not so hard if the APs are purely just converting ethernet to 
wireless. If there is any authing on the AP then it would be tougher. 
And a centralised DHCP issuer is important i.e. just one address range 
across all APs so when moving APs there is no dhcp change, no auth 
change, just a client reconnecting to the SSID. I guess this is not 
exactly what you are talking about but organising such protocols to work 
properly does become much more complex, and no we didn't have so much 
joy that way.

We have a wireless ISP in Wellington, New Zealand called CafeNET and 
thats all the APs do i.e. wireless to ethernet for large zones of the 
city homed back to a central controller. I have walked along our main 
central city street, Lambton Quay and carried on a conversation moving 
between at least 3 APs. I usually walked about 200 - 350m  depending my 
destination so could be using quite a few APs

The asterisk box in question is not blocked by the ISP.

Driving is different, but walking is okay, and the street noise masks 
the other occasional glitches, so I may think its doing better than it 
is, it can be noisy and hard to hear in any event with a mobile as well.

I don't do it so much any more because the cellphone charges got lower 
and I got tired of two devices, especially one that ran out of 
batteries. But I did for a few months to prove the point you are asking 
about.

Cheers Duncan

Michael Graves wrote:

>On Sat, 30 Aug 2008 11:51:49 -0500, Karl Fife wrote:
>
>  
>
>>Has anyone ever really, truly, actually held on to a Wi-SIP call while
>>moving from the range of one AP to the range of another AP in the same
>>network?  
>>
>>Let's say a 'YES' only counts if you had a bona-fide handoff.  In other
>>words, you began in place 'A' (within range of AP#1 but OUTSIDE the
>>range of AP#2), AND THEN MOVED to place 'B' (in range of AP#2, but
>>completely outside the range of AP#1) WITYOUT dropping the call.  
>>
>>Supposedly it's possible with compliant hardware using 802.11f -
>>Inter-Access Point Protocol (IAPP), but given how ALL standards ALWAYS
>>work together PERFECTLY, 100% of the time :-), I'm guessing that it
>>doesn't work.  Can anyone speak to this from experience?
>>
>>-Karl
>>    
>>
>
>Karl,
>
>I'm guessing that it was not common. 802.11f handoffs reportedly take
>100ms which is considered too long for streaming applications like
>voice and video.
>
>The 802.11r standard was only agreed upon and released days ago. This
>specifies FAST BSS transition specifically to saisfy such applications.
>Not sure if any hardware supports this as yet.
>
>http://en.wikipedia.org/wiki/IEEE_802.11r
>
>Michael
>--
>Michael Graves
>mgraves<at>mstvp.com
>http://blog.mgraves.org
>o713-861-4005
>c713-201-1262
>sip:mjgraves at pixelpower.onsip.com
>skype mjgraves
>fwd 54245
>
>
>
>
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