Wireshark · Wireshark-users: Re: [Wireshark-users] RTCP: Calculate round trip delay (Bishwarup)

[Bishwarup <bishwarup.pramanik@xxxxxxxxxxxxxx>]

I am sorry I couldn't make out anything with the answers so I am giving an example here.

I have an RTCP packet (Sender report) with the following specifications.

Frame 3494 (114 bytes on wire, 114 bytes captured)
    Arrival Time: Jan  9, 2007 11:37:42.890920000
    Time delta from previous packet: 0.004804000 seconds  
    Time since reference or first frame: 47.108231000 seconds

Last SR timestamp: 556982720 (0x2132e1c0)
Delay since last SR timestamp: 308288

All I know is that 890920000 would give me the number of milliseconds elapsed since the first packet.

Now to calculate the round trip delay, I won't do this..

Wrong ->   RTD = 890920000 - 556982720 - 308288

I want to know that what I need to do with the three numbers above to calculate the round trip delay?



Anders Broman (AL/EAB) wrote:

Hi,
When you look at the RTP timestamps do the come up as correct NTP timestamps?
It's not uncommon for clients to fill in the timestamp incorrectly.
Best regards
Anders

Gerry Brown wrote:

Make sure to read the RFC 3550.  The values are not always strictly binary. For instance, NTP is sec/millisecs.  The value of DLSR is represented as 1/65536 of a sec ticks.

gerry

 

 

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