[VoiceOps] SIP trunk providers emitting RTP packets containing wrong number of samples

[Jeff Brower]

  Liudvikas-

If you can send me a pcap (anonymized) I can run it through our  
media/decoder/packet tools and probably be able to tell you what is  
going on.

The pcap can contain multiple RTP streams, SIP, etc as long as the  
stream(s) of interest are in there.

-Jeff

Quoting Liudvikas Bukys <Liudy at bukys.org>:

> My company (a SIP equipment manufacturer) has noticed a sudden  
> flurry of problems related to RTP streams containing some packets  
> with the wrong number of samples (different from what was  
> negotiated).  Our equipment negotiates 20ms packets, we're seeing  
> the emission of a few 5ms packets with MARK bit set, before the 20ms  
> packets start flowing.    I theorized that some vendor's SBC or  
> Media Gateway has released software that causes this.
>          It has erupted at multiple customers.  I thought there was  
> no commonality of carrier or trunk provider, but today I heard a  
> report that T-Mobile is definitely implicated and reproducible.   
> Other sources are possible too.
>
>     
>    Has anyone else noticed this?
>     
>    Does anyone have a good contact for SIP-related matters at T-Mobile?
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