A friend in the community was trying to connect an SMF made by another
manufacturer with an SBI interface and found a big problem with Open5GS.
All of the code in the part that generates the Resource URI
from HTTP.location is invalid.
For example, suppose we create a Resource URI with SMContext as below.
{apiRoot}/nsmf-pdusession/<apiVersion>/sm-contexts/{smContextRef}
In this case, Open5GS extracted the {smContextRef} part of the HTTP.location
and appended it to the beginning
{apiRoot}/nsmf-pdusession/<apiVersion>/sm-contexts/.
This implementation may not work properly if the apiRoot changes.
Consider a different port number as shown below.
<HTTP.location>
127.0.0.4:9999/nsmf-pdusession/v1/sm-contexts/1
The SMF may send an apiRoot to the AMF with a changed port number,
in which case the AMF must honor it.
Therefore, instead of extracting only the smContextRef from HTTP.location,
we modified it to use the whole thing to create a Resource URI.
We modified all NFs that use HTTP.location in the same way, not just SMFs.
A situation in which you establish two sessions and release both of them.
In the first SESSION, the UE normally sent PDUSessionResourceReleaseResponse
and PDU session release complete. However, these were not sent when releasing
the second SESSION.
At this point, when the UE tried to do a deregistration,
the SMF was not properly handling the exception.
I've just fixed this.
[ETSI TS 128 552 V16.9.0](https://www.etsi.org/deliver/etsi_ts/128500_128599/128552/16.09.00_60/ts_128552v160900p.pdf):
Registration type label is not provided.
A nonstandard PLMNID label is added to achieve uniqueness.
- 5.3.1.3 Number of PDU sessions requested to be created by the SMF
PLMNID and SNSSAI are defined during PDU session creation processing.
Some requests can be rejected during processing before label values are known.
Those requests are not counted under particular labels.
To count also such requests, the basic metric with empty labels is exposed too.
```
fivegs_smffunction_sm_pdusessioncreationreq{plmnid="",snssai=""} 1
fivegs_smffunction_sm_pdusessioncreationreq{plmnid="00101",snssai="1000009"} 1
```
- 5.3.1.4 Number of PDU sessions successfully created by the SMF
```
fivegs_smffunction_sm_pdusessioncreationsucc{plmnid="00101",snssai="1000009"} 1
```
- 5.3.1.5 Number of PDU sessions failed to be created by the SMF
```
fivegs_smffunction_sm_pdusessioncreationfail{cause="400"} 1
```
Example for one successful and one failed (during creation processing) PDU session creation:
```
fivegs_smffunction_sm_pdusessioncreationreq{plmnid="",snssai=""} 2
fivegs_smffunction_sm_pdusessioncreationreq{plmnid="00101",snssai="1000009"} 1
fivegs_smffunction_sm_pdusessioncreationsucc{plmnid="00101",snssai="1000009"} 1
fivegs_smffunction_sm_pdusessioncreationfail{cause="400"} 1
```
Expose SM metrics with labels according to ETSI TS 128 552 V16.13.0 in
SMF by using hash.
The metrics are named respecting the rule:
<generation>_<measurement_object_class>_<measurement_family_name>_<metric_name_as_in_TS_128_552>
Existing gauge sessions_active is renamed!
Since slice itself is not unique, the plmnid label is exposed in
addition to snssai.
Exposed metrics example:
-standard gauges:
fivegs_smffunction_sm_sessionnbr{plmnid="00101",snssai="1000009"} 0
fivegs_smffunction_sm_qos_flow_nbr{plmnid="00101",snssai="1000009",fiveqi="9"} 0
-nonstandard counters:
fivegs_smffunction_sm_n4sessionestabfail{cause="71"} 68
fivegs_smffunction_sm_n4sessionreport 1
fivegs_smffunction_sm_n4sessionreportsucc 1
fivegs_smffunction_sm_n4sessionestabreq 1
In case there are multiple AMF registered to NRF, SMF would pick only
the first AMF from the list.
In the case of sending PDU Session Establishment Accept from SMF to
AMF, this would mean a high chance of failure since the AMF might
be different than the original requester, and would not know about a
particular UE.
Modify SMF to use ServingNfId field from original request
SmContextCreateData from AMF to determine to which AMF should it send
PDU Session Establishment Accept message.
A problem occurred when there was one SGWU/UPF and multiple SGWC/SMF.
When SGWU and UPF create a session, if the SEID is the same,
the existing session information is used without creating an additional session.
These problems were solved by using the F-SEID including IP information
in the process of checking the existing session.
For video in VoNR, multiple QosFlow is required in one session.
In the past, since only one Session Modification Message was supported,
QoS-Flow was put into several Session Messages one by one and processed.
Now that multiple QoS-Flows can be supported,
it is optimized to process one session modification message.
All process will be forcely exited if it failed to encode the S1AP/NGAP/GTP/PFCP message. It is to make sure there was no problem with the encoding of open5gs.
Sukchan Lee
Bostjan Meglic
Gaber Stare
Matej Gradisar
mitmitmitm