From herlesupreeth@gmail.com Tue Mar 3 15:24:10 2020 From: supreeth herle To: sr-users@lists.kamailio.org Subject: Re: [SR-Users] Dynamically change the transport protocol from UDP to TCP to avoid fragmentation Date: Tue, 03 Mar 2020 15:23:55 +0100 Message-ID: In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0703397071==" --===============0703397071== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Hello Everyone, I solved this issue. It was totally unrelated to Kamailio. I solved the issue by having proper DRB settings in eNB. Thanks and Regards, Supreeth On Thu, 27 Feb 2020 at 14:39, supreeth herle wrote: > Hello Everyone, > > I have an IMS setup using Kamailo and is working as expected when the 4G > Core Network and IMS is running in a single VM. However, when running in > two different VMs registration is successful but calling fails. As per the > scripts in kamailio ims example folder for P-CSCF, uac module is used to > generate OPTIONS message to achieve a kind of NATPINGING to UEs. > The ping achieved in this way times out with 408 when IMS and Core Network > is run in different VMs. > > I suspect that the increasing packets size could be the issue for UE not > responding to OPTIONS from P-CSCF (I have verified that OPTIONS message > from P-CSCF is reaching the eNB). In this aspect, I would like to switch > the transport protocol to TCP when MTU is greater than 1300 (please guide > me if my thinking of switching to TCP to tackle NAT issue is wrong). > > I have explored the following options: > > tcp_reuse_port=yes > udp_mtu=1300 > udp_mtu_try_proto=TCP > > But, when I use these options, any request message which hit 1300 MTU mark > are not sent out at all (in my case it is the NOTIFY request from SCSCF) > and Kamailio has a warning saying that binding to address failed as the > address is already in use. > > Following is the small part of the log: > > Feb 27 14:31:15 epc-ims /usr/local/sbin/kamailio[19712]: DEBUG: > ims_registrar_scscf [registrar_notify.c:2275]: > notification_event_process(): About to free notification > Feb 27 14:31:15 epc-ims /usr/local/sbin/kamailio[19730]: NOTICE: