updates to readme for slicing 01.

README.md

@@ -32,7 +32,7 @@ The configuration files and scripts are in the [multi_upf](multi_upf) directory.
 
 The configuration files and scripts are in the [slicing_01](slicing_01) directory.
 
-## Network Slicing 02
+## Network Slicing 02 (TODO)
 
 - In this scenario, we have 2 S-NSSAI representing two network slices (each consisting of 1 SMF and 1 UPF). 
 - UE1 connects to both slice 1 and slice 2 using two separate PDU sessions.

slicing_01/README.md

@@ -1,13 +1,19 @@
-# 5GC Setup: Slicing 01 (WIP)
+# 5GC Setup: Slicing 01
 
-This is WIP. See [Issues](#issues).
-
-- [5GC Setup: Slicing 01 (WIP)](#5gc-setup-slicing-01-wip)
+- [5GC Setup: Slicing 01](#5gc-setup-slicing-01)
   - [Deployment scenario](#deployment-scenario)
+  - [How to run](#how-to-run)
   - [VM placement](#vm-placement)
-  - [Issues](#issues)
   - [Debugging](#debugging)
-    - [Clearing all subscriber information using Mongodb](#clearing-all-subscriber-information-using-mongodb)
+    - [Using loopback addresses as PFCP interfaces](#using-loopback-addresses-as-pfcp-interfaces)
+    - [SMF selection error](#smf-selection-error)
+    - [Duplicate Mongodb entries](#duplicate-mongodb-entries)
+      - [Using Mongodb database](#using-mongodb-database)
+      - [Clearing all subscriber information using Mongodb](#clearing-all-subscriber-information-using-mongodb)
+      - [Clearing urilist collection when free5gc is stopped](#clearing-urilist-collection-when-free5gc-is-stopped)
+  - [Enhancements](#enhancements)
+    - [SMF filtering and selection](#smf-filtering-and-selection)
+
 
 ## Deployment scenario
 
@@ -18,27 +24,71 @@ This is WIP. See [Issues](#issues).
 
 The configuration files for this deployment are in the [config](config) directory.
 
+## How to run
+
+The [scripts](scripts) directory contains various scripts for running the setup. Obviously, each script should be run from the proper VM, i.e. UPF1 script should be run from the UPF1 VM.
+- [run_5gc](scripts/run_5gc.sh): Run the free5gc core.
+- [run_upf](scripts/run_upf.sh): Run the UPF functions. Run with positional arguments as `./run_upf 1` to run UPF1 and similarly for UPF2. The positional arguments are used to select the proper configuration file.
+- [run_gnb](scripts/run_gnb.sh): Run the UERANSIM gNB
+- [launch_ue](scripts/launch_ue.sh): Run the UE. Run with positional arguments as `./launch_ue.sh 1` to run UE1 and similarly for UE2.
+
+**IMPORTANT**: See instructions for [using loopback addresses as PFCP interfaces](#using-loopback-addresses-as-pfcp-interfaces) before running.
+
+
 ## VM placement
 
 The VM placement is the same as the [multi_upf](../multi_upf) scenario. Please see the [README](../multi_upf/README.md) there.
 
-## Issues
-- Two SMFs are not working together. The second SMF instance does not respond to the AMF and gives the following error during PDU establishment.
+
+## Debugging
+
+### Using loopback addresses as PFCP interfaces 
+
+To route packets from outside the local machine (i.e. PFCP packets from UPF1 or UPF2 VM) to the loopback addresses used as PFCP interfaces for SMF1 and SMF2, enable `route_localnet`.
+
+```
+sudo sysctl -w net.ipv4.conf.all.route_localnet=1
+```
+### SMF selection error
+
+It is **very important** the SMF configuration files should only contain the S-NSSAIs which are supported by the UPF. For instance, if SMF1 only supports UPF1, and UPF1 only supports S-NSSAI 1, then **do not** put any other S-NSSAI in SMF1 configuration file!
+
+Including any other S-NSSAI than those supported by the UPF can lead to AMF selecting the wrong SMF, leading to the following error.
 
 ![smf_error](../images/smf_error.jpg)
 
-## Debugging
+This is due to the following.
+- The SMF selection procedure only filters SMFs based on S-NSSAI and **does not look at UPF information**. This can be seen here [https://github.com/free5gc/amf/blob/6e0202ce2de6366856b005e5a5722745e420008f/consumer/sm_context.go#L90](https://github.com/free5gc/amf/blob/6e0202ce2de6366856b005e5a5722745e420008f/consumer/sm_context.go#L90).
+- With reference to the deployment shown above, this means that including S-NSSAI 2 in SMF1 configuration leads to the AMF selecting SMF1 for PDU session 2, even though UPF1 does not support it. 
+
+
+
+
+
+
+### Duplicate Mongodb entries
+
+The mongodb entries are not cleared when free5gc is stopped.
+This leads to the following issues.
+
+- UE subscription information remaining in the database  
+- Obsolete NF instances registered with the NRF remaining in the database. The relevant collections are `NfProfile` and `urilist`. Example `NfProfile` for SMF can be seen [here](logs/smf_nfprofile.json).
+
+
+#### Using Mongodb database
+Run the mongodb CLI and switch to free5gc database using `use free5gc`.  
+See a list of all collections using `show collections` .
 
-### Clearing all subscriber information using Mongodb
-Run the mongodb CLI and switch to free5gc database.  
+Information can be extracted from mongodb in JSON format as follows:
 ```
-$ use free5gc
+mongo free5gc --eval "printjson(db.NfProfile.findOne({nfType: 'SMF'}))" > smf_nfprofile.json
 ```
-See a list of all collections using `show collections`  
 
-Remove all subscription information
+#### Clearing all subscriber information using Mongodb
+
+
+All subscriber information can be removed using the following:
 ```
-db.NfProfile.remove({})
 db.policyData.ues.amData.remove({})
 db.policyData.ues.smData.remove({})
 db.subscriptionData.authenticationData.authenticationStatus.remove({})
@@ -48,3 +98,67 @@ db.subscriptionData.provisionedData.amData.remove({})
 db.subscriptionData.provisionedData.smData.remove({})
 db.subscriptionData.provisionedData.smfSelectionSubscriptionData.remove({})
 ```
+
+#### Clearing urilist collection when free5gc is stopped
+
+- In the `urilist` collections, multiple instances of the same NF with different `NfInstanceId` exists in the database. Thus, there exists obsolete links to NF instances.
+- Separate `NfInstanceId` exists for the same NF across different runs because in the init function, a random uuid string is generated everytime. See [https://github.com/free5gc/smf/blob/main/context/context.go#L21](https://github.com/free5gc/smf/blob/main/context/context.go#L21)
+- A similar issue occurs with the `NfProfile` collection.
+
+To clear, run the following from mongodb CLI.
+```
+db.NfProfile.remove({})
+db.urilist.remove({})
+```
+
+**Note**: The updated script [run_5gc.sh](scripts/run_5gc.sh) includes the above two commands, so obsolete NF information is cleared when the core goes down.
+
+
+## Enhancements
+
+### SMF filtering and selection
+- The available SMFs are filtered by S-NSSAI only. The relevant code is [https://github.com/free5gc/nrf/blob/386a6bdda516b64da43dd1711e3893528deaf0b9/producer/nf_discovery.go#L287](https://github.com/free5gc/nrf/blob/386a6bdda516b64da43dd1711e3893528deaf0b9/producer/nf_discovery.go#L287). This can be verified by running the following query in mongodb. 
+
+  ```
+  db.NfProfile.find({
+      $and: [
+          {
+              "nfType": "SMF"
+          },
+          {
+              "smfInfo.sNssaiSmfInfoList": { $elemMatch: {
+                      "sNssai.sd": "112233"
+                  }
+              }
+          },
+      ],
+  },
+  {
+      "ipv4Addresses": 1
+  })
+  ```
+
+- The parameters used for filtering SMF are S-NSSAI and DNN. This can be seen here.
+  ```go
+  {ServiceNames:{isSet:true value:[nsmf-pdusession]} RequesterNfInstanceFqdn:{isSet:false value:} TargetPlmnList:{isSet:true value:[{"mcc":"208","mnc":"93"}]} RequesterPlmnList:{isSet:false value:<nil>} TargetNfInstanceId:{isSet:false value:<nil>} TargetNfFqdn:{isSet:false value:} HnrfUri:{isSet:false value:} Snssais:{isSet:true value:[{"sst":1,"sd":"112233"}]} Dnn:{isSet:true value:network2} NsiList:{isSet:false value:<nil>} SmfServingArea:{isSet:false value:} Tai:{isSet:false value:<nil>} AmfRegionId:{isSet:false value:} AmfSetId:{isSet:false value:} Guami:{isSet:false value:<nil>} Supi:{isSet:false value:} UeIpv4Address:{isSet:false value:} IpDomain:{isSet:false value:} UeIpv6Prefix:{isSet:false value:<nil>} PgwInd:{isSet:false value:false} Pgw:{isSet:false value:} Gpsi:{isSet:false value:} ExternalGroupIdentity:{isSet:false value:} DataSet:{isSet:false value:<nil>} RoutingIndicator:{isSet:false value:} GroupIdList:{isSet:false value:<nil>} DnaiList:{isSet:false value:<nil>} SupportedFeatures:{isSet:false value:} UpfIwkEpsInd:{isSet:false value:false} ChfSupportedPlmn:{isSet:false value:<nil>} PreferredLocality:{isSet:false value:} AccessType:{isSet:false value:<nil>} IfNoneMatch:{isSet:false value:}}
+  ```
+- If more than one SMF is available for a given S-NSSAI, the first instance is chosen. The current implementation does not support any other selection criteria. The relevant code is [https://github.com/free5gc/amf/blob/6e0202ce2de6366856b005e5a5722745e420008f/consumer/sm_context.go#L100](https://github.com/free5gc/amf/blob/6e0202ce2de6366856b005e5a5722745e420008f/consumer/sm_context.go#L100).
+
+- The following shows the result of filtering SMF by S-NSSAI. Very little information is included which can be used for SMF selection.
+
+  ```go
+  {ValidityPeriod:100 NfInstances:[{NfInstanceId:d86056f0-da2d-4901-88b6-18263f1163f4 NfType:SMF NfStatus:REGISTERED HeartBeatTimer:0 PlmnList:0xc0004f6048 SNssais:0xc0004f6078 PerPlmnSnssaiList:[] NsiList:[] Fqdn: InterPlmnFqdn: Ipv4Addresses:[127.0.0.62] Ipv6Addresses:[] AllowedPlmns:<nil> AllowedNfTypes:[] AllowedNfDomains:[] AllowedNssais:<nil> Priority:0 Capacity:0 Load:0 Locality: UdrInfo:<nil> UdmInfo:<nil> AusfInfo:<nil> AmfInfo:<nil> SmfInfo:0xc0000ae680 UpfInfo:<nil> PcfInfo:<nil> BsfInfo:<nil> ChfInfo:<nil> NrfInfo:<nil> CustomInfo:map[] RecoveryTime:<nil> NfServicePersistence:false NfServices:0xc0004f6138 NfProfileChangesSupportInd:false NfProfileChangesInd:false DefaultNotificationSubscriptions:[]}] NrfSupportedFeatures:}
+  ```
+- SMF selection criteria are given in 3GPP TS 23.501 Section 6.3.2.
+
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