MBG RTP Local Streaming for Minet Phones

[inquiringmind]

We have a case where RTP Local Streaming is not working for extension to extension calls for Minet phones on the same LAN with the same public NAT IP address.  Would either double-natting or PATing cause the MBG not to recognize that the two Minet phones are on the same LAN?  In other words, what does the MBG look at specifically in the Minet packets to determine if a call is being setup between two phones on the same LAN?

[dilkie]

when the phone registers, it reports it's ip address (which is internal)
the connection ip is also noted.
If 2 phones have the same connection ip, they are considered behind the same NAT and thus *can* local stream to each other.
If one of them is behind a second NAT (double NATTED), then that will not work. We assume that anything behind the NAT facing the internet is internally routable.

So is local streaming not working, ie no or one-way audio, or the calls have media going back to mbg?

[inquiringmind]

Two phones with the same connection IP are having the RTP route from one phone to the MBG and then back to the same LAN to the other phone when local streaming is enabled.

[dilkie]

okay, so the other reasons why local streaming won't work when the network conditions are suitable.

- call recording is enabled (you cannot have local streaming if calls are also being recorded)
- same codec is not used in both call setups.
- both sets do not support the same srtp cipher capabilities.

[inquiringmind]

1.  MBG CRE is not enabled
2.  Same codec is being used on both phones
3.  The same srtp cipher capabilities should be supported

Q1.  Would different 6900 model Minet sets running the same 1.8.10 firmware behave differently?
Q2.  If the source port indicated with the private IP address is different than the source port indicated with the NAT public IP address (i.e. Port Address Translation) would that make a difference in behavior?

[dilkie]

A1. no, the model won't matter, all the 69xx series support the same capabilities (same s/w under the hood with different h/w drivers)
A2. when connected to MBG, the port and address indicated in the media response from the set is not taken into account, it's noted for use in local streaming but doesn't factor into the decision.

if you have a tug log you can share showing a call between the two, you can PM it to me and I'll take a look.

-lee