Forum Discussion

Copper Contributor

Aug 05, 2019

Most calls with Teams Direct Routing become one way audio

Have set up Direct Routing with an Audiocodes SBC and am testing features with my account in Teams only mode. I can make and receive calls just fine but it seems on most calls after about a minut...

MCT

Aug 07, 2019

Hi jguel, where is your SBC deployed? Is it nat'ted? In case there is NAT used: did you configure NAT rules on the SBC, too?

There is a good blog post regarding SBC Teams Direct Routing and NAT here: https://www.ucguys.com/2018/08/one-way-audio-with-microsoft-direct-routing-with-audiocodes-mediant-sbc-when-using-a-nat.html

Copper Contributor

Aug 07, 2019

It is NAT'd and I do have NAT rules set up. I don't think that's the problem because as I said the audio is two way in the beginning of the call and only becomes one way after a minute or two. Plus it's not every call but it is most calls.

tracyurbina
Copper Contributor
Apr 16, 2020
I am having this issue with Audiocodes SBC but its after 15 min. Wondering if you were able to find a fix? jguel
- Erik365Online
  MCT
  Apr 21, 2020
  15 minutes sounds like session timer or srtp re-keying related, to me. Do you use a secured connection with Sip TLS and SRTP?
  You might want to check the IP Profiles and the Media Security settings for the trunks on the SBC.
- jguel
  Copper Contributor
  Apr 16, 2020
  tracyurbina
  
  Determined it was a firewall issue - the firewall engineers could not figure out why it was happening but it was definitely firewall. Why it was so intermittent for us though I don't know. Way I figured that out was convinced the network guys to instead of NAT'ing the IP and Interface that was connecting to Office 365 was to not NAT it and assign the public IP directly to that interface and put it on the outside so it bypasses the firewall completely. Once this was done everything worked. Since that fixed the issue I convinced them to just leave it like that as the SBC has it's own ways of mitigating unauthorized access attempts.
  
  We were using fortigate firewalls if that helps. If you are having this issue and you are using a NAT try what I did and see if it fixes the problem.

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