Wireshark · Wireshark-users: Re: [Wireshark-users] Packet capture point

[Guy Harris <guy@xxxxxxxxxxxx>]

On Apr 20, 2009, at 10:44 AM, Jacek T. wrote:

> I'm trying to measure delay in 802.11 network and I need in witch  
> layer (in out) packet are captured.
> When capturing outgoing packets, do I get the time of packet  
> entering 2nd layer (queue) or packet exiting queue?

It could depend on the operating system, but if you're capturing  
traffic being sent by the machine on which you're doing the capturing,  
the packets are probably delivered at the time the driver gets them,  
not at the time they're transmitted.

Note also that the *receive* time stamp isn't necessarily accurate,  
given that the packet is time stamped somewhere in the driver, which  
might be some time after the packet is received by the network adapter.