* In this demo the image tags and commits which were used are listed below, follow the [Building images](./BUILD_IMAGES.md) to build images with below tags.
You can also retrieve the images from `docker-hub`. See [Retrieving images](./RETRIEVE_OFFICIAL_IMAGES.md).
| CNF Name | Branch Name | Tag used at time of writing | Ubuntu 18.04 | RHEL8 |
In this tutorial we are going to explore slicing feature of OAI 5G core network. Here we will validate -
* UPF selection based on S-NSSAI
* SMF selection based on S-NSSAI
* NRF selection based on S-NSSAI (With help of NSSF)
* AMF selection based on S-NSSAI (With help of NSSF - Next Release, March 2022)
* Single UE with multiple S-NSSAIs (With the help of commercial tool dsTest)
A Network Slice is defined within a PLMN and it incorporates the 5G Core and 5G RAN components. Network slice is identified as Single Network Slice Selection Assistance Information (S-NSSAI). A S-NSSAI is consist of Slice/Service type (SST) and Slice Differentiator (SD). SST is mandatory filed which defines expected slice behavior in terms of features and services. Whereas SD is optional field which can be used to differentiate amongst multiple slices. Currently 3GPP allows up to eight (8) S-NSSAIs in the NSSAI sent in signaling messages between the UE and the Network, means a single UE may be served by at most eight Network Slices at a time. SST length is 8 bits so it can provides 2^8= 256 SST values from which there are reserved values O to 127 for standardized SSTs (e.g. SST 2 = URLCC, SST 3 = MIoT, SST 4 = V2X etc.).
###### Slicing current status in OAI 5G CN -
* Role of NSSF -> NSSF currently supports, slice slection during pdu session establishment request. When AMF is not locally configured with NRF information, then with the help of NSSF it discovers appropriate NRF based on S-NSSAI provided.
* Role of AMF -> AMF slectes first available SMF from the NF instance list (of SMF) provided by appropriate NRF.
* Role od SMF -> SMF can associates with multiple UPFs at same time as in slice 2 and 3 from above figure. UPF is selected here based on S-NSSAI and DNN.
As shown in figure above, there are 3 S-NSSAIs configured (Can be differentiated with colors) viz. <br/>
Here AMF, NSSF, UDM, UDR, AUSF are common to all slices. SMF and UPF in S-NSSAI 2 and 3 have same NRF hence both UPFs are discoverable to both SMF. You can verify in the logs that both SMFs are successfullt associated to both UPFs in S-NSSAI 2 and 3. Here number of SMFs/UPFs for registered under single NRF is part of operator network planning.<br/>
######Let's begin !!
* Steps 1 to 4 are similar as previous tutorials such as [minimalist](./DEPLOY_SA5G_MINI_DS_TESTER_DEPLOYMENT.md) or [basic](./DEPLOY_SA5G_BASIC_DS_TESTER_DEPLOYMENT.md) deployments. Please follow these steps to deploy OAI 5G core network components.
## 5. Deploying OAI 5g Core Network ##
* We deploy `basic` version 5g core with additional component oai-nssf. We will use `docker-compose` to deploy 5g core as below -
```bash
oai-cn5g-fed/docker-compose$ docker-compose -f docker-compose-slicing-basic-nrf.yaml up -d
Creating network "demo-oai-public-net" with driver "bridge"
Creating network "oai-public-access" with the default driver
Creating network "oai-public-core" with the default driver
Creating oai-nrf-slice12 ... done
Creating oai-nssf ... done
Creating oai-ext-dn ... done
Creating mysql ... done
Creating oai-nrf-slice3 ... done
Creating oai-spgwu-slice2 ... done
Creating oai-udr ... done
Creating vpp-upf-slice3 ... done
Creating oai-udm ... done
Creating oai-ausf ... done
Creating oai-amf ... done
Creating oai-smf-slice3 ... done
Creating oai-smf-slice1 ... done
Creating oai-smf-slice2 ... done
Creating oai-spgwu-slice1 ... done
```
* Make sure all services are healthy -
```bash
oai-cn5g-fed/docker-compose$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4b75e9b715d3 oai-spgwu-tiny:develop "/openair-spgwu-tiny…" 46 seconds ago Up 45 seconds (healthy) 2152/udp, 8805/udp oai-spgwu-slice1
5e52b529455f oai-smf:develop "/bin/bash /openair-…" 47 seconds ago Up 46 seconds (healthy) 80/tcp, 9090/tcp, 8805/udp oai-smf-slice2
1da7df33427a oai-smf:develop "/bin/bash /openair-…" 47 seconds ago Up 46 seconds (healthy) 80/tcp, 9090/tcp, 8805/udp oai-smf-slice1
b8c7a13ba869 oai-smf:develop "/bin/bash /openair-…" 47 seconds ago Up 46 seconds (healthy) 80/tcp, 9090/tcp, 8805/udp oai-smf-slice3
fb4ba1055b04 oai-amf:develop "/bin/bash /openair-…" 47 seconds ago Up 47 seconds (healthy) 80/tcp, 9090/tcp, 38412/sctp oai-amf
63e1e7302835 oai-ausf:develop "/bin/bash /openair-…" 48 seconds ago Up 47 seconds (healthy) 80/tcp oai-ausf
c560aaa93b91 oai-udm:develop "/bin/bash /openair-…" 49 seconds ago Up 48 seconds (healthy) 80/tcp oai-udm
f3c4ecfac1db oai-upf-vpp:develop "/openair-upf/bin/en…" 50 seconds ago Up 48 seconds (healthy) 2152/udp, 8085/udp vpp-upf-slice3
80aa4e12169a oai-udr:develop "/bin/bash /openair-…" 50 seconds ago Up 48 seconds (healthy) 80/tcp oai-udr
c509b4711de3 oai-spgwu-tiny:develop "/openair-spgwu-tiny…" 50 seconds ago Up 49 seconds (healthy) 2152/udp, 8805/udp oai-spgwu-slice2
c1bd7b8afb8c mysql:5.7 "docker-entrypoint.s…" 51 seconds ago Up 49 seconds (healthy) 3306/tcp, 33060/tcp mysql
e014638c3e12 oai-nrf:develop "/bin/bash /openair-…" 51 seconds ago Up 49 seconds (healthy) 80/tcp, 9090/tcp oai-nrf-slice3
bf6544a04f1f oai-nssf:develop "/bin/bash /openair-…" 51 seconds ago Up 49 seconds (healthy) 80/tcp, 8080/tcp oai-nssf
33a43a237af6 ubuntu:bionic "/bin/bash -c ' apt …" 51 seconds ago Up 49 seconds (healthy) oai-ext-dn
0459b8ca6490 oai-nrf:develop "/bin/bash /openair-…" 51 seconds ago Up 50 seconds (healthy) 80/tcp, 9090/tcp oai-nrf-slice12
```
## 6. Getting a `ransim` docker images ##
We are using 3 different ran simulators viz.ueransim, rfsimulator and gnbsim for slice 2,3 and 4 repectively. Each of them has there set of features, and one can use as per need basis. You can pull docker images from official repositories as below -
```bash
$ docker pull rohankharade/gnbsim:latest
$ docker pull rohankharade/ueransim:latest
$ docker pull rdefosseoai/oai-gnb:develop
$ docker pull rdefosseoai/oai-nr-ue:develop
```
And re-tag them for tutorials' docker-compose file to work.
```bash
$ docker image tag rohankharade/gnbsim:latest gnbsim:latest
$ docker image tag rohankharade/ueransim:latest ueransim:latest
$ docker image tag rdefosseoai/oai-gnb:develop oai-gnb:develop
$ docker image tag rdefosseoai/oai-nr-ue:develop oai-nr-ue:develop
```
## 7. Executing `ransim` Scenario ##
We run first, ueransim, gnbsim and rfsimulator gnb then rfsimulator UEs. Here we deploy rfsimulator UEs later as we need to make sure rfsimulator gnb is connected to AMF successfully.
```bash
oai-cn5g-fed/docker-compose$ docker-compose -f docker-compose-slicing-ransim.yaml up -d gnbsim ueransim oai-gnb oai-nr-ue1
Creating gnbsim ... done
Creating ueransim ... done
Creating rfsim5g-oai-gnb ... done
Creating rfsim5g-oai-nr-ue1 ... done
```
Wait a bit
```bash
oai-cn5g-fed/docker-compose$ docker-compose -f docker-compose-slicing-ransim.yaml ps -a
