Teams Direct Routing - SIP Options Warning

Question

Hello,

I have set up a Ribbon SBC with Teams Direct Routing. TLS Connection is ok, but I get this Message:
The Session Border Controller exists in our database (your administrator created it using the command New-CSOnlinePSTNGateway). But we have difficulties determining SIP Options status. Please check in 15 minutes.

I checked the firewall and see that the SBC is sending SIP Options to Teams and that I get a response from Teams. But there are no connections from Teams to the SBC, so Teams doesn't send any SIP Options:
IP SBCPublicIP.27171 > 52.114.7.24.5061: Flags [P.], seq 23200:23708, ack 15521, win 12500, length 508
IP SBCPublicIP.27171 > 52.114.7.24.5061: Flags [P.], seq 23708:23925, ack 15521, win 12500, length 217
IP 52.114.7.24.5061 > SBCPublicIP.27171: Flags [.], ack 23925, win 2053, length 0
IP 52.114.7.24.5061 > SBCPublicIP.27171: Flags [P.], seq 15521:16006, ack 23925, win 2053, length 485
IP SBCPublicIP.27171 > 52.114.7.24.5061: Flags [.], ack 16006, win 12500, length 0
IP SBCPublicIP.27795 > 52.114.75.24.5061: Flags [P.], seq 23200:23925, ack 15521, win 12500, length 725
IP 52.114.75.24.5061 > SBCPublicIP.27795: Flags [P.], seq 15521:16006, ack 23925, win 2050, length 485
IP SBCPublicIP.27795 > 52.114.75.24.5061: Flags [.], ack 16006, win 12500, length 0

I opened a MS Support case, but they want me to check the Teams client connection and even worse want me to do test calls, which wont work obviously. There are no client connectivity issues.

I even deleted all the configuration, waited 48h and reconfigured everything. Same behaviour as before. Do I miss anything?

Answer 1

Short Update:

I could solve my issue with the help of the SBC vendor (thx again to TE-Systems for their quick support).

Originally I was connecting my (single) SBC with both of my MS Tenants, using only one Port (5067) for TLS, via only one NIC, using only one public IP.
But of course using 2 public SBC-FQDN, pointing to this single Public IP. This wouldn't work. You need to use different Ports for the Tenants.

I had to reconfigure my SBC for using different TLS Ports for each tenant (Tenant1: 5067, Tenant2: 5068) and updated the Teams Config accordingly.
After some replication time the OPTIONS Packets immediately started coming in again and calls in both directions are working fine now for both tenants.

Answer 2

@Daniel Straß ,

Please note that you need to configure TeamsUpgradePolicy to ensure incoming calls are received in Teams. Users must be in Teams Only mode, which you can do by assigning them the "UpgradeToTeams" instance of TeamsUpgradePolicy.

---

If the response is helpful, please click "Accept Answer" and upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 3

Similar issue. Two tenants connected with one SBC (TE-Systems anynode. Each tenant configured as seperate node), but for only one tenant at a time, Direct Routing is working in both directions. For the other tenant, only outbound calls to Teams are ok. No inbound calls from the Teams side! In the SBC logs I can't see anything coming from Microsoft. Not even OPTIONS Packets.
Funny thing is, that I can "switch the issue"! By disabling the node for the working tenant in my SBC, the other one immediately starts receiving OPTIONS Pakets from Microsoft and calls in both directions are possible! As if MS would have problems with sending OPTIONS to both nodes (both behind the same NIC/IP).
I've openned a ticket with the SBC vendor. They usually provide fast and reliable support. Other than Microsoft...

Answer 4

Hello,

We are facing the same issue.

On the WAN interface of our router, we can see our SBC communicating with Teams (sipX.pstnhub.microsoft.com on port 5061), butwe did not see any communication from Teams IP to our SBC. We have waited 48 hours after we create the SBC link on our tenant, but still no communication.
I tried to do a telnet from outside my network (any website providing online telnet ) to my SBC on TCP port 5061, and it works fine. I'm connected and i saw the communication with tcpdump on my router. So this is not a firewall nor a network issue.
It is as if Teams server does not try to communicate with our SBC.
As there is no communication, i have the TLS warning in teams.

Did you find a solution ?

Answer 5

Similar Issue, any update on this. Even updated SBC firmware as per vendor. Appears to be a generic issue. pointing towards Firewall or static routes which are clean anyways.