ConnectionContext creation for LTE PDN Connection.

ConnectionContext creation for LTE PDN Connection.

[Sjur BRENDELAND]

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Hi all,

We have started to investigate LTE impact on oFono, 
specifically how to integrate LTE and initial PDN connection,
and we have some questions regarding this.

This raises some questions about the handling of
ConnectionContexts.

When a terminal attach to LTE network it would
normally do an implicit context activation request
associated to attach request (+CGATT=1).
When the context activation is completed this will
result in an event notifying about the activated PDN
connection according to
27.007 10.1.19 Packet Domain event reporting +CGEREP.

+CGEV: ME PDN ACT <cid>

At this point we have a "connection context" in the modem.

The question is then, how should we model this in oFono?
Should we assume/require that a Connection Context
already is created by ConnMan and pre-exists in 
oFono (possibly with a flag indicating that this
represents the initial PDN, or perhaps just taking
the "internet" ConnectionContext)?
Or should oFono automatically create a Connection Context?

Furthermore, should oFono automatically proceed and
set Active=true, bind the connection to a network interface
and set network interface in state UP, or should the
ConnectionContext initially set Active=false, 
waiting for ConnMan to activate it?


Regards,
Sjur

Re: ConnectionContext creation for LTE PDN Connection.

[=?unknown-8bit?q?R=C3=A9mi?= Denis-Courmont]

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	Hello,

On Monday 29 November 2010 16:46:43 ext Sjur BRENDELAND, you wrote:
> This raises some questions about the handling of
> ConnectionContexts.
> 
> When a terminal attach to LTE network it would
> normally do an implicit context activation request
> associated to attach request (+CGATT=1).

Yeah. So the ConnectionManager cannot be 'Powered' off in LTE.

> When the context activation is completed this will
> result in an event notifying about the activated PDN
> connection according to
> 27.007 10.1.19 Packet Domain event reporting +CGEREP.
> 
> +CGEV: ME PDN ACT <cid>
> 
> At this point we have a "connection context" in the modem.
> 
> The question is then, how should we model this in oFono?
> Should we assume/require that a Connection Context
> already is created by ConnMan and pre-exists in
> oFono (possibly with a flag indicating that this
> represents the initial PDN, or perhaps just taking
> the "internet" ConnectionContext)?

The modem driver ought to know what the default PDN is, and match it to the 
correct oFono primary context. no?

> Or should oFono automatically create a Connection Context?
> 
> Furthermore, should oFono automatically proceed and
> set Active=true, bind the connection to a network interface
> and set network interface in state UP,

Definitely not. This would interfere with any other existing IP connection, say 
WiFi.

> or should the ConnectionContext initially set Active=false,
> waiting for ConnMan to activate it?

This assumes that the default PDN would be the Internet connection. For data-
only LTE, this might work. But wouldn't this fail miserably for networks with 
separate PDN for IMS and Internet?

-- 
Rémi Denis-Courmont
Nokia Devices R&D, Maemo Software, Helsinki

Re: ConnectionContext creation for LTE PDN Connection.

[Marcel Holtmann]

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Hi Remi,

> > Or should oFono automatically create a Connection Context?
> > 
> > Furthermore, should oFono automatically proceed and
> > set Active=true, bind the connection to a network interface
> > and set network interface in state UP,
> 
> Definitely not. This would interfere with any other existing IP connection, say 
> WiFi.

why would bringing an interface up interfere? We are doing this right
now. Just the IP assignment is done by ConnMan, but the interface
up/down status is controlled by oFono or even BlueZ in case of
Bluetooth.

Regards

Marcel

Re: ConnectionContext creation for LTE PDN Connection.

[Sjur =?unknown-8bit?q?Br=C3=A6ndeland?=]

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Hi Marcel,

Marcel Holtmann wrote:
>> > Or should oFono automatically create a Connection Context?
>> >
>> > Furthermore, should oFono automatically proceed and
>> > set Active=true, bind the connection to a network interface
>> > and set network interface in state UP,
>>
>> Definitely not. This would interfere with any other existing IP connection, say
>> WiFi.
>
> why would bringing an interface up interfere? We are doing this right
> now. Just the IP assignment is done by ConnMan, but the interface
> up/down status is controlled by oFono or even BlueZ in case of
> Bluetooth.

So does this imply that you think oFono should set Active=true and
and bring up the interface as soon as the Initial PDN  is avilable?

What about the ConnectionContext, should oFono automatically create a
new one if needed?

Regards,
Sjur

Re: ConnectionContext creation for LTE PDN Connection.

[Denis Kenzior]

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Hi Sjur,

On 11/30/2010 05:26 AM, Sjur Brændeland wrote:
> Hi Marcel,
> 
> Marcel Holtmann wrote:
>>>> Or should oFono automatically create a Connection Context?
>>>>
>>>> Furthermore, should oFono automatically proceed and
>>>> set Active=true, bind the connection to a network interface
>>>> and set network interface in state UP,
>>>
>>> Definitely not. This would interfere with any other existing IP connection, say
>>> WiFi.
>>
>> why would bringing an interface up interfere? We are doing this right
>> now. Just the IP assignment is done by ConnMan, but the interface
>> up/down status is controlled by oFono or even BlueZ in case of
>> Bluetooth.
> 
> So does this imply that you think oFono should set Active=true and
> and bring up the interface as soon as the Initial PDN  is avilable?
> 
> What about the ConnectionContext, should oFono automatically create a
> new one if needed?

I think it is too early to tell, we need more information about how LTE
works.  Right now I'm not convinced LTE belongs on the ConnectionManager
interface at all.

Regards,
-Denis

Re: ConnectionContext creation for LTE PDN Connection.

[Remi.Denis-Courmont]

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----- Message d'origine -----
> why would bringing an interface up interfere? We are doing this right
> now. Just the IP assignment is done by ConnMan, but the interface
> up/down status is controlled by oFono or even BlueZ in case of
> Bluetooth.

Logically whoever sets the IP parameters should bring the interface administratively up. This is layer 3.

oFono does layer 2. It should either create/remove the interface and/or play with the dormant and/or carrier flags.

-- 
Rémi

Re: ConnectionContext creation for LTE PDN Connection.

[Marcel Holtmann]

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Hi Remi,

as I mentioned before, please do NOT break threading.

> > why would bringing an interface up interfere? We are doing this right
> > now. Just the IP assignment is done by ConnMan, but the interface
> > up/down status is controlled by oFono or even BlueZ in case of
> > Bluetooth.
> 
> Logically whoever sets the IP parameters should bring the interface administratively up. This is layer 3.
> 
> oFono does layer 2. It should either create/remove the interface and/or play with the dormant and/or carrier flags.

If you think we should change the current behavior, then please send
patches for oFono and BlueZ and also ConnMan to fix this.

Regards

Marcel