Re: Calculate Hop by Hop delay

[Guy Harris <guy () alum mit edu>]

On Dec 31, 2008, at 7:07 AM, Tassadaque Zia wrote:

> Can i calculate per hop delay using pcap liberary using pcap_stats  
> or with some other function

No.

The only statistics pcap_stats() are those relevant to libpcap, such  
as the number of packets dropped when capturing.

To calculate per-hop delay, you'd have to somehow arrange that time  
stamps be put on packets when transmitted (*AND* that the hosts'  
clocks are reasonably closely synchronized, so that the difference  
between the time when a packet was received and the time stamp put on  
the packet when it was sent actually reflects the per-hop delay  
without also reflecting the time skew between the sending and  
receiving machine).

You'd also have to deal with delays *inside* hosts doing routing  
(i.e., the difference between when the packet was received and when it  
was sent).
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