Merge branch 'vpp_native_build' into 'develop'

Instructions updated for bare metal setup

See merge request oai/cn5g/oai-cn5g-upf-vpp!24

docs/INSTALL_ON_HOST.md

@@ -39,7 +39,7 @@ After successful dependencies install,
 @@@@ Installing vpp @@@@
 [0/1] Install the project...
 -- Install configuration: "debug"
-make[1]: Leaving directory '/home/rohan/oai-cn5g-upf-vpp/vpp/build-root'
+make[1]: Leaving directory 'oai-cn5g-upf-vpp/vpp/build-root'
 ##### VPP compiled #####
 VPP UPG initializing
 Installing VPP
@@ -48,3 +48,43 @@ Installing VPP
 ```bash
 /oai-cn5g-upf-vpp/build/scripts$ ./build_vpp_upf -w
 ```
+### Networking Setup 
+We need veth pairs type of interfaces for vpp switch. So we create three veth pairs (n3, n4 and n6) as below -
+```bash
+sudo ip link add name n4in type veth peer name n4out
+sudo ip link add name n3in type veth peer name n3out
+sudo ip link add name n6in type veth peer name n6out
+```
+
+Now we connect one end of veth pair to vpp switch - <br/>
+Sample init.conf (upf config)
+```bash
+create host-interface name n3in
+set interface ip table host-n3in 2
+set interface ip address host-n3in 192.168.72.203/24
+set interface state host-n3in up
+
+create host-interface name n4in
+set interface ip address host-n4in 192.168.70.203/24
+set interface state host-n4in up
+
+create host-interface name n6in
+set interface ip table host-n6in 1
+set interface ip address host-n6in 192.168.73.203/24
+set interface state host-n6in up
+```
+
+And then we connect other end of veth pair to the core network docker bridges (demo-oai (n4), cn5g-access(n3), cn5g-core (n6)).
+```bash
+sudo brctl addif demo-oai n4out
+sudo brctl addif cn5g-access n3out
+sudo brctl addif cn5g-core n6out
+
+sudo ip link set dev n4out up
+sudo ip link set dev n6out up
+sudo ip link set dev n3out up
+```
+
+The bridge used here are created by docker. For more details checkout [docker-compose file](https://gitlab.eurecom.fr/oai/cn5g/oai-cn5g-fed/-/blob/master/docker-compose/docker-compose-basic-vpp-nrf.yaml) used to set up core network.
+
+You can create your own bridge or linux namespace for networking purpose, if you dont want to use docker bridges.