[srslte-users] Configuring srsEPC to accept MME unknown UEs

Andre Puschmann andre.puschmann at softwareradiosystems.com
Thu Aug 2 08:09:17 UTC 2018


Hey Marek,

On 01/08/18 12:47, Marek Sebera wrote:
> Hi Andre, and all interested,
> 
> the important question was buried by other replies, so I post it once more
> 
> --snip--
> 
> I'm considering implementing the emergency-attach
> procedure, however I'm not sure, how to test it while developing.
> 
> I have only one SDR (USRP B210), so I cannot test srsUE against srsENB
> using 2 SDRs, what I'd expect be the easiest way to tests/implement.
> 
> Do you have any idea, how to simulate emergency attach from real device?
> 
> Or if it's possible to work without SDRs, how to run locally srsUE
> against srsENB without actually transmitting to the air?

Yes, I kind of hoped Joe would jump in to promote his excellent sockrf
patches. As this is not the case, I'll do that now. You'll find them
here here [1].

Hope that helps
Andre



[1] https://github.com/srsLTE/srsLTE/pull/148


> 
> --snip--
> 
> Thank you
> Marek
> 
> On 07/30/2018 10:23 AM, Andre Puschmann wrote:
>> Hey,
>>
>> the emergency-attach procedure is not supported right. All the documents
>> you listed seem to be correct. Needless to say we are happy to review
>> pull-requests ;-)
>>
>> Cheers
>> Andre
>>
>>
>> On 28/07/18 11:56, Marek Sebera wrote:
>>> Hello,
>>>
>>> i'm investigating possibility of using srsLTE for disaster relief (ie.
>>> when existing PLMNs are over-loaded or their infrastructure fails) and
>>> laboratory testing (security testing MEs/UEs without need to change SIM
>>> within or degrade from LTE to 3G/2G networks)
>>>
>>> Reading TS 23.167 (IMS Emergency Sessions) and related parts of 23.401,
>>> 24.301, 33.401, and others, it seems that Emergency Session shall allow
>>> unauthenticated / unknown UE to access limited or all services, as per
>>> network configuration.
>>>
>>> TR 23.715 specifies RLOS (Restricted Local Operator Services) to
>>> Unauthenticated UEs in both IMS and non-IMS attach
>>> TS 23.401 section 4.3.12.1 specifies (d) "All UEs are allowed"
>>> TS 33.401 section 5.1.3 and 5.1.4 specifies that if UE cannot be
>>> authenticated that EIA0 and EEA0 shall be used
>>> TS 23.167 specifies that while in Emergency Session the IMS (IP
>>> Multimedia Services) could be available
>>>
>>> So I suspect, that we should be able to configure EPC so, that it
>>> provides services (telephony, sms, PDN) to UEs that cannot be
>>> authenticated against HSS (user_db.csv).
>>>
>>> [++++]
>>>
>>> So the question is: Is it possible to allow unknown UE to access network
>>> services, without being previously known to HSS ? If so, how?
>>>
>>> - If it's possible only for Emergency Session, is it possible to enforce
>>> emergency attach from ENB (ie. convert existing standard attach to
>>> emergency attach type or let UE know, to repeat attach request in
>>> emergency mode?)
>>>
>>> - If it's possible for normal-style attach, please provide guidance or
>>> example configuration
>>>
>>> [++++]
>>>
>>> Obviously we could not provide non-NULL EIA/EEA algorithms, because we
>>> don't know SIM/USIM Key/OPc and other identifiers
>>>
>>> And finally, if I just missed the right 3GPP TS/TR document, just point
>>> it out, I think, I'm capable of providing implementation within srsLTE,
>>> if the process is documented already.
>>>
>>> Thank you
>>> Marek Sebera
>>>
>>>
>>>
>>> _______________________________________________
>>> srslte-users mailing list
>>> srslte-users at lists.softwareradiosystems.com
>>> http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
>>>
>>
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>>


-- 
Andre Puschmann

Software Radio Systems (SRS)
http://www.softwareradiosystems.com

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