Hi Masumeh.
In case it helps, I have had little success implementing reliable CSFB
using open5gs and osmo-* - but actually, I think that most of the
problems may reside in the configuration and operation of the eNodeB
rather than in the software relevant to this list.
My analysis of the situation at this point it that one would need to
look at some diagnosis of the process inside the eNodeB, and it looks
like you are using srsRAN, so maybe you can glean some more information
from srsran logs related to the CSFB process once open5gs has signaled
to the eNodeB that it should fall back the UE to 2G
I do note something very obvious in your MSC log -
DPAG ERROR SGs-UE(imsi:001010000000015)[0xaaaafc29f880]{SGs-NULL}: Will
not Page (conf_by_radio_contact_ind == true) (sgs_iface.c:481)
Try to get familiar with the state of the entries in the MSCs VLR (show
subscriber cache) - and observe from initial attach on 4G, how this is
communicated over SGs and the resulting state in the VLR. I recently
fixed some problems in open5gs that were provoking this "unpage-able"
state in osmo-msc. You are using the most recent version of open5gs,
correct?
BTW, Is there something I am supposed to learn from looking at the pcap
files that you attached?
It is not that I want to be that guy complaining about bug report style,
so just some friendly advice, if you make other people download, open
and analyze a pcap file that contains nothing of relevance, those people
may in some cases, feel less likely to want to help you out in the
future. - I feel it is possible that you just blindly captured traffic
on some interfaces. Also, most of the config you attached is also not
relevant.
I hope you would not take it as dissuasion, but I would offer that
getting CSFB working reliably is unfortunately still, not just a matter
of some simple config change, and if you are not familiar enough with
the protocols involved to recognize them, then you should be prepared
for a steep learning curve if you are going to continue experimenting
with it. I hope you do, as it would be great to make further progress
with getting reliable CSFB.
