On Thu, Sep 8, 2011 at 3:50 PM, Dan Lan <
danlanweb@gmail.com> wrote:
> Hi,
> I run into a weird situation. My media gateay handle voice call with 2
> different RTP ports for send & receive
>
> Here is what happened. (ps: both gateway and FS are all on public IP, no NAT
> involved)
> 1. Incoming call INVITE from gateway to FS
> Connection Information (c): IN IP4 100.100.100.100 (This is my media
> gateway IP address)
> Media Description, name and address (m): audio 5294 RTP/AVP 18 0 4
> 2. FS response with session progress with media information
> Connection Information (c): IN IP4 200.200.200.200
> Media Description, name and address (m): audio 22428 RTP/AVP 0
> 3. I start to see some RTP traffic exchange between FS and GW
> from FS (22428) --> GW (5294)
> from GW (5292) --> FS (22428)
> please note: the GW use two DIFFERENT PORT for RTP, one for sending and one
> for receiving
> 4. For a while (about 5 secs, I think)
> The RTP flow change on FS side to become, (there is no RTCP packet during
> the time)
> from FS (22428) --> GW (5292)
> from GW (5292) --> FS (22428)
> In other word, the FS now sending RTP to 5292 instead of 5294 (which was
> intended in INVITE SDP message)
>
> And, of course, I cannot hear the voice on GW side after this.
>
> Anyone encounter this before? Are there any paramaters that might involved
> in this auto changing RTP port behavior of FS?
>
> Any direction for me is appreciated, I will play around with this, and post
> back my result to community.
>
> Dan Lan
>