Wifi Calling issue

[CarlT]

Hi All

We have an issue when wifi calling over our wifi.

We have a Guest ssid, this tunnels back to a pair of mx450 concentrators and breaks out on the lan, then goes via the firewall to reach the internet.

We cannot make any calls, the phone rings but no voice is heard.

The strange thing is, we have 2 pairs of concentrators, of we change it so it tunnels back to our other pair, it seems to work fine.

Any idea what this could be?

Cheers

[ww]

Both concentrators use the same firewall  and internet? My guess would be that something  is blocked  there

[CarlT]

Hi, yes same firewall and internet.

[alemabrahao]

Have you noticed any issues regarding VRRP on the hubs? When you say tunneled is it because you are using VPN: tunnel data to a concentrator in the SSID configuration?

[CarlT]

Hi, no vrrp issues as far as I am aware, everything else seems to work fine.

Yes, we are using vpn tunnel to a concentrator

[alemabrahao]

Do you have any firewall rules that might be limiting something? Have you tried creating a traffic shaping rule?

[CarlT]

They both end up on the same LAN as each other so the firewall rules must be irrelevant in this case.  

How would traffic shaping help?

cheers

[alemabrahao]

@CarlT  are they on the same network, but are the firewall rules identical on both hubs? Traffic shaping is just an attempt, I can't say if it will be relevant to your case.

In this case, the best option is to capture packets from a device that you use for testing.

[PhilipDAth]

Are these two pairs active/active and do you have any VPN firewall rules?

If so, if traffic goes out one VPN hub, the VPN firewall will create a stateful rule for the return traffic - but if the traffic returns via the over hub that temporary stateful rule does not exist on that other unit, and will result in the return traffic being blocked.

[CarlT]

Hi

When you say VPN hub, you mean the Meraki devices ?

There are no rules on them as they are dedicated vpn concentrators, it does not let you do any firewall rules etc.

What I will try is shutting one off to force all the traffic to one of them just in case vrrp is doing something funny ?

[Agus]

Hi,

what application to use for calling? whatsapp or other call application? i think if call is ring, it already communicate end to end user, but no voice heard maybe something policy for source and destination for certain call application (TCP port or UDP maybe not open?

Thanks

[CarlT]

Hi

If I do a packet capture, I can see that the wifi calls are encrypted with ESP port 4500, I see this go out and come back in on the AP, so it cannot be blocking.

The strange thing is, my phone works fine on EE, also using ESP, on Voda it doesnt work, though if we move it to the other wireless concentrator, it works fine.