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[asterisk-users] OT - Is handover included in DECT GAP ?


 
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michiel at vanbaak.info
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PostPosted: Thu Jan 10, 2008 6:31 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

On 11:22, Thu 10 Jan 08, Olivier wrote:
Quote:
Hi,

Do you if a DECT-GAP (or DECT-CAP) compliant handset MUST or MAY support
roaming and handover and are these functions transparent for handset (then,
these functions are implemented in DECT base stations) ?

Roaming/handover functionality is implemented in DECT-GAP.
I dont know if all handsets allow it, but I think they do.

--

Michiel van Baak
michiel at vanbaak.eu
http://michiel.vanbaak.eu
GnuPG key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x71C946BD

"Why is it drug addicts and computer afficionados are both called users?"
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robl at linx.net
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PostPosted: Thu Jan 10, 2008 7:28 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

On Thu, Jan 10, 2008 at 11:22:29AM +0100, Olivier wrote:
Quote:
Hi,

Do you if a DECT-GAP (or DECT-CAP) compliant handset MUST or MAY support
roaming and handover and are these functions transparent for handset (then,
these functions are implemented in DECT base stations) ?

Yes. It is a capability of the handset, where, as the user is moving about,
the handset is continually scanning for the best channel/frequencies
available from the base station. If a better signal than the one the user is
currently using becomes available, (perhaps they have gone into a different
room or moved behind a tree etc. meaning the current channel is weaker, then
the handset will switch to using the better channel during the call.)

There are a few systems out there that support multiple base stations which,
to the handset, all look like the same registered base. (i.e, the handset
only registers/authenticates once with the system (and not every base
station) and then as the user moves about the handset, by virtue of always
looking for the best channel, will hop from one base to the next. It does
require that the system in the middle manage the database of registrations
etc.)

I've seen such capability on Siemens HICOM and Bosch PBXs, for example. All
the DECT base stations are wired back to a central card in the system.

I don't know if there is a standalone DECT IP offering supporting similar.

The timing/clocking to support seamless roaming between the base stations is
complicated and has to be very precise, so I imagine that such a system
would need to have one central controller (and the SIP gateway function)
with DECT base stations all wired out from there, rather than lots of
independent DECT bases with Ethernet, that talk to a central unit over IP
and somehow hand off the call.

So to span multiple buildings you would probably need dedicated copper pairs
or fibre to connect in the remote base stations to the central system.

That is certainly the way it worked when I was last tinkering with DECT
stuff. Although the Siemens switches could have multiple remote shelves
connected over fibre to different buildings, the DECT bases all had to be
connected via copper cables (and be powered on by) a central card in the
main shelf, and could not be connected to a card in a remote shelf. (Or, you
could have multiple PBXs and handsets roaming between different systems, but
that starts to get expensive for maybe 10 users!)

I have some detailed specs on it somewhere if you want more technical info.

Rob
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michiel at vanbaak.info
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PostPosted: Thu Jan 10, 2008 7:47 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

On 12:28, Thu 10 Jan 08, Robert Lister wrote:
Quote:
On Thu, Jan 10, 2008 at 11:22:29AM +0100, Olivier wrote:
Quote:
Hi,

Do you if a DECT-GAP (or DECT-CAP) compliant handset MUST or MAY support
roaming and handover and are these functions transparent for handset (then,
these functions are implemented in DECT base stations) ?

Yes. It is a capability of the handset, where, as the user is moving about,
the handset is continually scanning for the best channel/frequencies
available from the base station. If a better signal than the one the user is
currently using becomes available, (perhaps they have gone into a different
room or moved behind a tree etc. meaning the current channel is weaker, then
the handset will switch to using the better channel during the call.)

There are a few systems out there that support multiple base stations which,
to the handset, all look like the same registered base. (i.e, the handset
only registers/authenticates once with the system (and not every base
station) and then as the user moves about the handset, by virtue of always
looking for the best channel, will hop from one base to the next. It does
require that the system in the middle manage the database of registrations
etc.)

I've seen such capability on Siemens HICOM and Bosch PBXs, for example. All
the DECT base stations are wired back to a central card in the system.

I don't know if there is a standalone DECT IP offering supporting similar.

The timing/clocking to support seamless roaming between the base stations is
complicated and has to be very precise, so I imagine that such a system
would need to have one central controller (and the SIP gateway function)
with DECT base stations all wired out from there, rather than lots of
independent DECT bases with Ethernet, that talk to a central unit over IP
and somehow hand off the call.

So to span multiple buildings you would probably need dedicated copper pairs
or fibre to connect in the remote base stations to the central system.

That is certainly the way it worked when I was last tinkering with DECT
stuff. Although the Siemens switches could have multiple remote shelves
connected over fibre to different buildings, the DECT bases all had to be
connected via copper cables (and be powered on by) a central card in the
main shelf, and could not be connected to a card in a remote shelf. (Or, you
could have multiple PBXs and handsets roaming between different systems, but
that starts to get expensive for maybe 10 users!)

I have some detailed specs on it somewhere if you want more technical info.

We have 2 different setups in production.
NEC-Philips ip-dect and the kirk/tiptel ip-dect.

The NEC-Philips one works with a dedicated server to
controll the registration etc, and all the radios are
connected to the normal ethernet network. No need for
dedicated copper/fiber, they simply communicate over the lan
with the central provisioning/managing server. The handsets
register with the closest radio and from that moment on they
can roam to all radios. Asterisk sees every handset as it's
own sip entry.

The kirk setup we deployed is with the skinny firmware.
It works basically like the NEC-Philips setup, but you dont
need a dedicated server to manage stuff because the main
basestation does this for you. It works with repeaters
instead of seperate base stations. As long as the repeater
can reach another repeater or the base station roaming works
fine. I read in their brochures you can also stack
basestations in multiple locations but I dont know how that
works.

--

Michiel van Baak
michiel at vanbaak.eu
http://michiel.vanbaak.eu
GnuPG key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x71C946BD

"Why is it drug addicts and computer afficionados are both called users?"
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anselm at hoffmeister-...
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PostPosted: Thu Jan 10, 2008 7:58 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

Am Donnerstag, den 10.01.2008, 12:31 +0100 schrieb Michiel van Baak:
Quote:
On 11:22, Thu 10 Jan 08, Olivier wrote:
Quote:
Hi,

Do you if a DECT-GAP (or DECT-CAP) compliant handset MUST or MAY support
roaming and handover and are these functions transparent for handset (then,
these functions are implemented in DECT base stations) ?

Roaming/handover functionality is implemented in DECT-GAP.
I dont know if all handsets allow it, but I think they do.

AFAIK "roaming" in the sense of using another than the default base
station is supported in even the cheapest handsets that are sold as
"GAP". This does work nicely with different vendors' base stations (as
it should), although in that case only basic functionality can be
achieved (like CALLER ID display, Call-on-Hold seems to work) - the
phone book feature, internal calls to other handsets and base station
configuration mostly do not work.

I have not yet seen a DECT/GAP phone that supports roaming while a call
is in progress, this would need the appropriate logic in the base
stations. I know such hardware exists ("Kirk"!?), but if not advertised,
the base stations most certainly do not have this feature. I expect that
this function requires additional support in the handset as well, so
using those 20$-handsets on your multi-k-$ roaming support base station
will probably not help...

BR
Anselm
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oza-4h07 at myamail.com
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PostPosted: Thu Jan 10, 2008 8:40 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

2008/1/10, Anselm Martin Hoffmeister <anselm at hoffmeister-online.de>:
Quote:

Am Donnerstag, den 10.01.2008, 12:31 +0100 schrieb Michiel van Baak:
Quote:
On 11:22, Thu 10 Jan 08, Olivier wrote:
Quote:
Hi,

Do you if a DECT-GAP (or DECT-CAP) compliant handset MUST or MAY
support
Quote:
Quote:
roaming and handover and are these functions transparent for handset
(then,
Quote:
Quote:
these functions are implemented in DECT base stations) ?

Roaming/handover functionality is implemented in DECT-GAP.
I dont know if all handsets allow it, but I think they do.

AFAIK "roaming" in the sense of using another than the default base
station is supported in even the cheapest handsets that are sold as
"GAP". This does work nicely with different vendors' base stations (as
it should), although in that case only basic functionality can be
achieved (like CALLER ID display, Call-on-Hold seems to work) - the
phone book feature, internal calls to other handsets and base station
configuration mostly do not work.

I have not yet seen a DECT/GAP phone that supports roaming while a call
is in progress,
that is what I call handover
roaming = without any ongoing call
handover = with ongoing call

this would need the appropriate logic in the base
Quote:
stations. I know such hardware exists ("Kirk"!?),


Kirk base stations support roaming and handover but it's very difficult to
know which handsets, beside Kirk handsets, support such feature as vendor
won't specify if "Kirk base stations don't support Siemens handsets, for
instance, because working feature set is very poor or because we don't want
to care or deal with non-Kirk handsets as we sell our own".

As Michiel said, having those features included in DECT-GAP (shall a
DECT-GAP compliant handset support every feature or some of them ?) might
explain why DECT-GAP compliance is more advertised than those 2 roaming and
handover features (which are never mentioned).

but if not advertised,
Quote:
the base stations most certainly do not have this feature.


I'm not certain but cheap handsets can be registered on multiple stations.
Whenever an outgoing call is made, one station is chosen by the handset.
For incoming calls, it's up to PBX (or caller) to call the right base
station.


I expect that
Quote:
this function requires additional support in the handset as well, so
using those 20$-handsets on your multi-k-$ roaming support base station
will probably not help...

BR
Anselm


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oza-4h07 at myamail.com
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PostPosted: Thu Jan 10, 2008 8:41 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

2008/1/10, Michiel van Baak <michiel at vanbaak.info>:
Quote:

On 11:22, Thu 10 Jan 08, Olivier wrote:
Quote:
Hi,

Do you if a DECT-GAP (or DECT-CAP) compliant handset MUST or MAY support
roaming and handover and are these functions transparent for handset
(then,
Quote:
these functions are implemented in DECT base stations) ?

Roaming/handover functionality is implemented in DECT-GAP.
Is it mandatory ?

I dont know if all handsets allow it, but I think they do.
Quote:

--

Michiel van Baak
michiel at vanbaak.eu
http://michiel.vanbaak.eu
GnuPG key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x71C946BD

"Why is it drug addicts and computer afficionados are both called users?"


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robl at linx.net
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PostPosted: Thu Jan 10, 2008 9:15 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

On Thu, Jan 10, 2008 at 01:47:39PM +0100, Michiel van Baak wrote:
Quote:
We have 2 different setups in production.
NEC-Philips ip-dect and the kirk/tiptel ip-dect.

The NEC-Philips one works with a dedicated server to
controll the registration etc, and all the radios are
connected to the normal ethernet network. No need for
dedicated copper/fiber, they simply communicate over the lan
with the central provisioning/managing server. The handsets
register with the closest radio and from that moment on they
can roam to all radios. Asterisk sees every handset as it's
own sip entry.

Interesting. Does that support handover between bases during a call,
or only registration to nearest base station?

Rob
--
Robert Lister - London Internet Exchange - http://www.linx.net/
sip:robl at linx.net - inoc-dba:5459*710 - tel: +44 (0)20 7645 3510
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robl at linx.net
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PostPosted: Thu Jan 10, 2008 9:46 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

On Thu, Jan 10, 2008 at 02:40:21PM +0100, Olivier wrote:

Quote:
that is what I call handover
roaming = without any ongoing call
handover = with ongoing call

this would need the appropriate logic in the base
Quote:
stations. I know such hardware exists ("Kirk"!?),

Kirk base stations support roaming and handover but it's very difficult to
know which handsets, beside Kirk handsets, support such feature as vendor
won't specify if "Kirk base stations don't support Siemens handsets, for
instance, because working feature set is very poor or because we don't want
to care or deal with non-Kirk handsets as we sell our own".

As far as I understand it, where you have a base station and one phone, you
are creating a cell consisting of one antenna. It is possible with DECT to
have one cell consisting of many antennas (base stations) Moving between
base stations in the same DECT cell is called handover. The handset
registers with any base in the same cell. If you only have one base station,
then the base station and cell are effectively the same thing.

The base stations have to be connected somehow to a central system that
manages the handover in the cell during a call, the system has to support
multiple base stations in the DECT cell. No additional functionality should
be needed in the handset, because it already has the capability to channel
hop between DECT channels during a call, without the user noticing.

Many DECT handsets (but not all) support registration with multiple DECT
cells (i.e. as well has having up to X handsets registered with the cell, a
handset can register with up to X bases.) This would support 'roaming' in
the sense that the handset would use the base it could register with. (i.e,
if you had one DECT handset registered with a base at home and at work, the
handset would work on both bases if the handset supports multiple bases.)
This could be called "roaming" between DECT cells and is done by the
handset, but handover between two completely different DECT cells during a
call is not possible.

In a large PBX installation, you can have both working, so that if a user
took a handset from one system in one city, to another office in another
city, and these PBXs were connected together, the "Home" PBX receives
registration request from the remote PBX, and diverts the calls for that
user to the remote PBX. I believe this is done by proprietary vendor
software magic though, and is not part of DECT itself.

Rob
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michiel at vanbaak.info
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PostPosted: Thu Jan 10, 2008 9:49 am    Post subject: [asterisk-users] OT - Is handover included in DECT GAP ? Reply with quote

On 14:15, Thu 10 Jan 08, Robert Lister wrote:
Quote:
On Thu, Jan 10, 2008 at 01:47:39PM +0100, Michiel van Baak wrote:
Quote:
We have 2 different setups in production.
NEC-Philips ip-dect and the kirk/tiptel ip-dect.

The NEC-Philips one works with a dedicated server to
controll the registration etc, and all the radios are
connected to the normal ethernet network. No need for
dedicated copper/fiber, they simply communicate over the lan
with the central provisioning/managing server. The handsets
register with the closest radio and from that moment on they
can roam to all radios. Asterisk sees every handset as it's
own sip entry.

Interesting. Does that support handover between bases during a call,
or only registration to nearest base station?

It supports handover between bases during a call.

--

Michiel van Baak
michiel at vanbaak.eu
http://michiel.vanbaak.eu
GnuPG key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x71C946BD

"Why is it drug addicts and computer afficionados are both called users?"
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