Re: Wireshark RTP Stream - Packet Lost in Neg value over the WAN‏

[Farooq Razzaque <farooq_mcp () hotmail com>]

Dear Lars
 
Really thanks for your support.
 
Can u please let me know that is this the wireshark or RTP behaviour of showing the duplicate packets in negative value 



 


 


> From: lars.ruoff () alcatel-lucent com
> To: wireshark-users () wireshark org
> Date: Mon, 26 Sep 2011 13:56:49 +0200
> Subject: Re: [Wireshark-users] Wireshark RTP Stream - Packet Lost in Neg value over the WAN‏
>
> Farooq,
> (I put this back on the list if you don't mind, so others can comment and it gets archived.)
>
> In reality, there were only 1744/4 = 436 unique RTP packets sent between the endpoints.
> But Wireshark captured each packet 4 times.
> (Note that your packet counts are always multiples of 4)
> Each duplicate packet (packet with same RTP sequence number) gives rise to a lost count of -1.
> Thus from the 1744, 436 were unique, the remaing 3/4 i.e. 1308 are duplicate.
> Thus a lost count of -1308, corresponding to -300% of the 100% unique packets.
> Hope this is clear.
>
>
> regards,
> Lars
>
>
> ________________________________
>
> From: Farooq Razzaque [mailto:farooq_mcp () hotmail com] 
> Sent: lundi 26 septembre 2011 12:21
> To: jaap.keuter () xs4all nl; RUOFF, LARS (LARS)** CTR **
> Subject: RE: [Wireshark-users] Wireshark RTP Stream - Packet Lost in Neg value over the WAN‏
>
>
> Dear Lars/Jaap
>
> Thanks for your support.
>
> we are SPANing the data on cisco switch and forwarding to Alcatel and Cisco recording machine.
>
> monitor session 2 source interface x
> monitor session2 destination interface x.
>
> Can u please let me know how the following can be seen by analysis engine by 4 times. how it is calculate
>
> Number of packet = 1744
> Lost -1308 (-300)
>
>
>
> <http://www.flamingtext.com/hmail.html> 
>
>
>
>
>
>
> > From: lars.ruoff () alcatel-lucent com
> > To: wireshark-users () wireshark org
> > Date: Mon, 26 Sep 2011 09:44:30 +0200
> > Subject: Re: [Wireshark-users] Wireshark RTP Stream - Packet Lost in Neg value over the WAN‏
> >
> > Hi,
> >
> > No, since you (almost) consistently have -300% all the time, it is most likely that every packet has been seen 
> > exactly 4 times by the analysis engine, but no packets have been lost.
> > (It is an artefact of the RFC3550 lost packets algorithm that duplicate packets are counted as negative losses)
> > However, as Jaap noted, in order to get more readable data, you should fix your capture setup issue which makes you 
> > see every packet multiple times.
> >
> > Regards,
> > Lars
> >
> >
> >
> > ________________________________
> >
> > From: wireshark-users-bounces () wireshark org [mailto:wireshark-users-bounces () wireshark org] On Behalf Of 
> > Farooq Razzaque
> > Sent: same! di 24 septembre 2011 19:04
> > To: wireshark-users () wireshark org
> > Subject: [Wireshark-users] Wireshark RTP Stream - Packet Lost in Neg value over the WAN‏
> >
> >
> > Dear All
> >
> >
> >
> >
> > Can u have a look at the attached screen shot of wireshark. In LOST COLUMN it is showing 300% , -299.7% pack lost. 
> >
> >
> >
> > Do u have any idea that are these packet loss is normal/abnormal.
> >
> >
> >
> > IP phones ( 172.20.24.x) are located in one branch and Recording machine (172.20.19.17) is located in other branch.
> >
> >
> >
> > SPANing is happing over the WAN via L2TPV3.
> >
> >
> >
> > IP Phones : 172.20.24.X (IP Phone)
> >
> >
> >
> > 172.20.19.17 (Recording machine) 
> >
> > ___________________________________________________________________________
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