Hello everyone,
I am encoutering an issue I can't explain, (nor the workaround).
The first issue was some of my users, in VPN, couldn't speak between them in softphone mode, ASA drop vpn to vpn flow.
So I saw in the community I could use a TRP as a workaround.
I configured it and was happy : vpn softphone users could speak to each other.
Recently, an issue came out randomly : PSTN outbound calls were strange : PSTN can hear the softphone user, the softphone user can't hear the PSTN.
VPN Softphone to PSTN call :
VPN to PSTN : ko
PSTN to VPN : ok
But
PSTN to VPN Softphone call :
VPN to PSTN : ok
PSTN to VPN : ok
I made some test and saw the issue was only on one of my PSTN_ISR.
On my TRP IOS router I did these commands :
POC_TRP#sh sccp connections
sess_id conn_id stype mode codec sport rport ripaddr conn_id_tx
67384406 67168750 mtp sendrecv pass_th 16598 18198 IP_VPN_SOFTPHONE
67384406 67168745 mtp sendrecv pass_th 16588 21948 IP_ISR_2
Total number of active session(s) 1, and connection(s) 2
POC_TRP#sh sccp connections
sess_id conn_id stype mode codec sport rport ripaddr conn_id_tx
67384395 67168590 mtp sendrecv pass_th 16506 17556 IP_VPN_SOFTPHONE
67384395 67168585 mtp sendrecv pass_th 16496 27304 IP_ISR_1
Total number of active session(s) 1, and connection(s) 2
Calls from IP_ISR_2 are all ok, the ones from IP_ISR_1 have the issue.
ISR1 & ISR2's config are quite the same (except IP address ).
When I do show sip call leg, as far as I can tell, everything is the same (I checked codec, it is the same on both ISR).
On the CUCM page, in MTP config, I unchecked "Trusted Relay Point" and every call was good.
I entered this command :
POC_TRP#sh sccp connections
sess_id conn_id stype mode codec sport rport ripaddr conn_id_tx
67384397 67168636 xcode sendrecv g711u 16522 23350 IP_VPN_SOFTPHONE
67384397 67168623 xcode sendrecv g711u 16520 17826 IP_ISR_1
Total number of active session(s) 1, and connection(s) 2
There are some differences : stype & codec are differents.
I have some questions :
1 - Is TRP the good way to ensure correct calls between VPN users in softphone ?
2 - Do I have to stay in TRP for my first need (VPN users softphone) ?
3 - What is the purpose of the checkbox "Trusted Relay Point" in the MTP configuration page ?
4 - Why can I have a different behaviour between the 2 ISRs while "TRP" is checked
5 - How/Where can I troubleshoot differences between the 2 ISRs ?
Best regards and thanks for your help !
Irwin
