In an Inter-RAT setup a UE could perform a TAU coming from a 2G/3G network.
In that case the UE/MS is unknown to the MME and it should request the
SGSN context (MM, PDP) from the old SGSN. This is done through the following
GTPv1C message exchange on the Gn interface of SGSN and MME:
SGSN <- MME: SGSN Context Request
SGSN -> MME: SGSN Context Response
SGSN <- MME: SGSN Context Acknowledge
Diagram with full set of steps can be found at 3GPP TS 23.401 D.3.6.
This commit doesn't aim to be a complete implementation of the mentioned
procedure, since it's quite a complex one, with lots of fields and logic
required. This so far only implements in general the minimally
successful case by filling as much as possible the required set of
fields.
This will allow for a base onto which do incremental improvements and
fixes while testing against UEs and SGSNs (such as osmo-sgsn, which
doesn't yet support this procedure but will potentially earn it soon).
The reverse direction, aka UE issuing cell reselection 4G->2G was
already implemented (same as here, initial non-complete implementation)
in open5gs-mmed in commit 3d693da73e.
Related: https://osmocom.org/issues/6294
Within the PathSwitchRequest packet,
the E-RABToBeSwitchedDLList has two bearers.
If the E-RAB-ID of both bearers is 5, the MME's list memory is destroyed
and the MME crashes. To fix this issue, we modified the code so that
the MME can work correctly with invalid S1AP messages.
This will be useful for other procedures where only the RAI is known,
but not the specific CI. This is the case of idle mobility from Gb or Iu
to EUTRAN, where MME needs to request contexts based on the RAI mapped
in the GUTI obtained from the UE during TAU.
This also makes the config more resilient in RIM scenario, where an SGSN
can be picked now even if CI doesn't match, instead of failing or faling
back to the default route SGSN.
Both types are defined under lib/proto/type.h, and the conversion
function is used in several different protocols, so let's better move it
to generic lib/proto/conv.h and remove the "gtp2" prefix.
The assert is checking for sess->session->name, but afterwards there's a
check to skip ses->session not being null, which means the assert can
crash while dereferencing sess->session.
In an Inter-RAT setup a UE could perform a RAU coming from a 4G network.
In that case the UE/MS is unknown to the SGSN and it should request the
SGSN context (MM, PDP) from the MME. This is done through the following
GTPv1C message exchange on the Gn interface of SGSN and MME:
SGSN -> MME: SGSN Context Request
SGSN <- MME: SGSN Context Response
SGSN -> MME: SGSN Context Acknowledge
This commit doesn't aim to be a complete implementation of the mentioned
procedure, since it's quite a complex one, with lots of fields and logic
required. This so far only implements in general the minimally
successful case by filling as much as possible the required set of
fields.
This will allow for a base onto which do incremental improvements and
fixes while testing against UEs and SGSNs (such as osmo-sgsn, which
doesn't yet support this procedure but will potentially earn it soon).
This commit doesn't implement the reverse direction, aka UE issuing cell
reselection 2G->4G. Initial support for this scenario will hopefully be
added soon as a follow-up patch, similar to this one.
Related: https://osmocom.org/issues/6294
In an Inter-RAT setup a UE could perform a RAU coming from a 4G network.
In that case the UE/MS is unknown to the SGSN and it should request the
SGSN context (MM, PDP) from the MME. This is done through the following
GTPv1C message exchange on the Gn interface of SGSN and MME:
SGSN -> MME: SGSN Context Request
SGSN <- MME: SGSN Context Response
SGSN -> MME: SGSN Context Acknowledge
This commit doesn't aim to be a complete implementation of the mentioned
procedure, since it's quite a complex one, with lots of fields and logic
required. This so far only implements in general the minimally
successful case by filling as much as possible the required set of
fields.
This will allow for a base onto which do incremental improvements and
fixes while testing against UEs and SGSNs (such as osmo-sgsn, which
doesn't yet support this procedure but will potentially earn it soon).
This commit doesn't implement the reverse direction, aka UE issuing cell
reselection 2G->4G. Initial support for this scenario will hopefully be
added soon as a follow-up patch, similar to this one.
Related: https://osmocom.org/issues/6294
This information will be required by the Gn interface in MME when
answering an SGSN with an "SGSN Context Response" message during MS cell
reselection EUTRAN->GERAN.
* [AMF/MME] UEContextReleaseCommand in Integrity (#2786)
Modified not to send UEContextReleaseCommand in Integrity Unprotected
NAS message such like Registration or Service request.
* [AMF/MME] UEContextReleaseCommand after Interity Protected (#2786)
Modified not to send UEContextReleaseCommand in Integrity Unprotected
NAS message such like Registration or Service request.
Allow network operators to omit the time zone in the 4G EMM Information
and 5G Configuration Update. This is useful for better compatibility
with some UEs.
The parameter is optional according to:
* 4G: 3GPP TS 24.301 Table 8.2.13.1
* 5G: 3GPP TS 24.501 Table 8.2.19.1.1
amf_ue->mac_failed flag to be cleared during security mode procedure but it was not.
At this point, the only way to cleare the amf_ue->mac_failed flag is by UE Context Release.
But I'd like to connect UEs as fast as possible without UE Context Release.
Based on the standard document below, when the UE is in the IDLE state,
we checked the implicit timer and tried to send a message to the UE,
but it doesn't work properly.
So, first of all, I deleted the related code.
- TS 24.301 Ch 5.3.7
If ISR is not activated, the network behaviour upon expiry of
the mobile reachable timer is network dependent, but typically
the network stops sending paging messages to the UE on the
first expiry, and may take other appropriate actions
- TS 24.501 Ch 5.3.7
The network behaviour upon expiry of the mobile reachable timer is network dependent,
but typically the network stops sending paging messages to the UE on the first expiry,
and may take other appropriate actions.
Move the config to the sgsn node instead of having a specific route with
specific format "default: route", since anyway internally it's already
applied to the sgsn object.
The 'data' struct used to specify the diameter dispatch options for the
MME callbacks was not being initialized properly, which meant that the
App id could contain garbage. This was preventing the callbacks from
being invoked when receiving ISD/CLR requests.
ogs_pool_init() shall be used in the initialization routine.
Otherwise, memory will be fragment since this function uses system malloc()
Compared with ogs_pool_init()
ogs_pool_create() could be called while the process is running,
so this function should use ogs_malloc() instead of system malloc()
Sukchan Lee
Pau Espin
Emanuele Di Pascale
Oliver Smith
Šimon Lukašík