What is the network namespace and the purpose in test.sh

When I run test case in test.sh, such as test theN3IWF case: TestNon3GPP, there are two pcap files, one is default_ns.pcap: is this for NGAP/NAS singnalling? and another UPFns.pcap: is this for PFCP and traffic capture file? why have these network namespace? can you explain more detail for this logic or solution? Another question is that why the src and dest ip address are the same one 10.200.200.1 for NGAP/NAS message? from my understanding in the SMG config, this ip is the SMF pfcp N4 interface address? a little confuse, can you help to clarify it? And for the access type is gNB, such as case TestRegistration, the src and dest ip address is 127.0.0.1, why use this llopback ip? can I change to another valid ip address or config the valid ip address on AMF and gNB N2 interface? thanks very much!

No.

Kinds of, but not completely.

You can think about we separate the UPF to another namesapce such as deploy it into a different VM.

As above.

Because the config is set as it is.

With the same IP, you still can have different address due to that address are define by multiple field such as IP, port, protocol.

Loopback ip is more easily to use because almost every host has it and we do not need to set the IP to system ourselves and we do not need to set the route.

You can change it to whatever you like.