· The UE shall initiate the detach procedure when:
- the UE is switched off
- the USIM is removed from the UE
- the EPS capability of the UE is disabled (detach for EPS services only)
- the UE in CS/PS mode 1 or CS/PS mode 2 of operation wishes to detach for both EPS services and non-EPS services or for non-EPS services only via a combined detach procedure etc...
· The UE initiates the detach procedure by sending a DETACH REQUEST message
· The Detach type IE included in this message indicates the type of detach. 4-bits are used for this purpose. 3-bits (LSBs) indicate whether the detach is for ‘EPS detach’ or ‘IMSI detach’ or ‘Combined EPS/IMSI detach’. Bit-4 indicates if it is ‘normal detach’ or ‘switch off’
· If the UE has a valid GUTI, the UE shall set the EPS mobile identity IE as GUTI. If the UE does not have a valid GUTI, then it shall populate the EPS mobile identity IE with its IMSI. If the UE has neither a valid GUTI nor a valid IMSI (with no USIM or invalid USIM), then the UE shall populate the EPS mobile identity IE with its IMEI
· If the UE is to be switched off, the UE shall try for a period of 5 seconds to send the DETACH REQUEST message. During this period, the UE may be switched off as soon as the DETACH REQUEST message has been sent
· When the DETACH REQUEST message is received by the network, with the Detach type IE set to ‘switch off’, the network shall not send a DETACH ACCEPT message to the UE
· When the DETACH REQUEST message is received by the network, with the Detach type IE set to ‘normal detach’, the network shall send a DETACH ACCEPT message to the UE
· If the Detach type IE set to ‘normal detach’ and if the UE doesn’t receive DETACH ACCEPT message before the timer T3421 is expired, it shall re-transmit the DETACH REQUEST message. Upon the 5th expiry of T3421 timer, the UE shall perform local detach
· The network and the UE shall deactivate the EPS bearer context(s) locally without peer-to-peer signalling between the UE and the MME
Reference: 3GPP TS 24.301Example: DETACH REQUEST for EPS services only (switch off)
Hi!I'm new here!May I ask you a question?What's the differences between EPS services & non-EPS services?Can't find the exactly definition in the related-spec.In my view,EPS services afford services(PS & CS) using LTE equipment,and the non-EPS services using 2G/3G equipment. am i right?Thanks!
ReplyDeletenon-EPS services are those provided by CS domain where as EPS services are provided by PS domain. refer to 24301
ReplyDeleteWhen I say, if UE attached for EPS services only, then if UE moves from LTE to 3G/2G, it need to do a fresh Attach/TAU. if
DeleteUE attached for combined Services (both EPS and Non EPS) then UE moves from LTE to 3G/2G without any such procedure.
Hi
ReplyDeleteWhen does the UE triggers Detach type IE = normal detach.
Thx
When you change Apn in device that time it sends Detach request with detach type IE Normal
DeleteThanks bro
ReplyDeleteNormal detach could be due to detach initiated by the UE for EPS services only or non-EPS services only etc
ReplyDeleteI was doing LTE integration with Lg Lucid UE. It sends detach request after 28sec of successful attach. How can I stop unwanted detach procedure initiated by UE. It says "Normal Detach+EPS Detach" in detach request. Any idea about how to avoid it.
ReplyDeleteHello, I have the same problem with a Samsung phone. I don't understand the reason for EPS Detach. Can anyone please explain ?
DeleteHi,
DeleteAkhilesh Kaushik/Dincer Beken
there are may possible reason for this kind of detach one is
If it is a IMS capable phone then it might be trying to attach to IMS PDN with PCO containing PCSCF addressrequest but in ActivateDefaultEPSBearerContextRequest message might be n/w is not assigning PCSF address in PCO.
solution:
Include the PCSCF address.i.e. for protocol Id 1 see 24.008 protocol configuration Options for more detail
As i was also encountering the same issue with Samsung S3/S4
I want to disconnect only from non eps services. Is there any AT command supported for that?
ReplyDeleteHi,
ReplyDeleteAkhilesh Kaushik/Dincer Beken
there are may possible reason for this kind of detach one is
If it is a IMS capable phone then it might be trying to attach to IMS PDN with PCO containing PCSCF addressrequest but in ActivateDefaultEPSBearerContextRequest message might be n/w is not assigning PCSF address in PCO.
solution:
Include the PCSCF address.i.e. for protocol Id 1 see 24.008 protocol configuration Options for more detail
As i was also encountering the same issue with Samsung S3/S4
how can you describe it in physical situation then?
ReplyDeletelike removal of battery is a detach with type switch off? and whats normal detach in that case?
I don't think that the UE gets a chance to even transmit "detach request" message when the battery is removed
Delete@Indu Shekhar,
DeleteDid you find any more info on the Use Case you mentioned ?
I would be interested to know more about it.
1. Remove simcard.
Delete2. Disconnect it from UI.
3. At+ cops=2
Hi,
ReplyDeleteCan you kindly explain me the detach cause "Explicit IMSI detach indication via A-IF(EAIF)".
Thanks ...
This procedure is used by the MME to indicate to the VLR that the UE has been detached from EPS services and
Deletetherefore the SGs association between the MME and the VLR has to be deactivated.
The procedure is also used by the MME to indicate to the VLR when a combined tracking area update procedure has
been rejected by the MME.
The Explicit IMSI detach from EPS services procedure aborts any other ongoing procedure related to this UE on the
SGs interface in the MME and in the VLR.
During CSFB procedures , i am getting TAU reject with cause 10 implicit detach , is this normal behavior ? its not happening for every TAU request
ReplyDeleteHi Joggy,
DeleteYes, I have seen this several times in the field. This could usually happen if the for example if there is mismatch in the active context reported by the UE and the network.
Here is the explanation from the spec. for this cause:
Cause #10 – Implicitly detached
This EMM cause is sent to the UE either if the network has implicitly detached the UE, e.g. after the implicit detach timer has expired, or if the EMM context data related to the subscription does not exist in the MME e.g. because of a MME restart.
I m facing in LTE with Samsung A5 mi phone
ReplyDelete
ReplyDeleteIf attach procedure is in process at the same time mobile has initiated detach procedure? What will Happen?
if i have only LTE network and i want my Mobile to latch to the network but not detach , what are the parameters need to be changed so the UE behave like a Data only UE, can we avoid combined attached procedure ,or can we avoid normal detach for smart phones so that a smart phone can use Data services
ReplyDeleteif i have only LTE network and i want my Mobile to latch to the network but not detach , what are the parameters need to be changed so the UE behave like a Data only UE, can we avoid combined attached procedure ,or can we avoid normal detach for smart phones so that a smart phone can use Data services
ReplyDeleteHi,
ReplyDeleteWhy UE get Detach type=3 and attach type = 2 in LTE detach and attach process
I have problem in 4G network with 2G fallback for cs services. Some time UE did not return to 4G network after cs fallback or us switch to 2G network. Some time problem is solved by on and off aeroplane mode. In MSc UE shown as imsi detached for EPS services. What is the reason of not return to LTE and is there any solution to this problem. Fast return to LTE is enable in 2G network
ReplyDeleteGreat
ReplyDeleteeNodeB for s1ap protocol.. details.
While doing repeated attach and detach test,i can see some times attach is failing . Will there be any time interval beteen my attach and detach test? Atleast ENODEB need some time to release the ue context?
ReplyDelete