I merely used the ping to demonstrate Wireshark's packet time stamping
(though in this case, it seems that the router responds immediately).
FWIW, a couple of NTP packets got captured too with a 34 ms round trip. I
was actually looking for an ARP request/response in consecutive packets on
the grounds that the router wouldn't delay ARP responses... I found one and
it was (claimed) 1.107 ms round trip. I make no claim as to the accuracy
of these timestamps.
NTP packets:
Frame 779: 90 bytes on wire (720 bits), 90 bytes captured (720 bits) on
interface 0
Interface id: 0 (en1)
Encapsulation type: Ethernet (1)
Arrival Time: Jan 14, 2017 10:22:46.628995000 PST
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1484418166.628995000 seconds
[Time delta from previous captured frame: 0.279231000 seconds]
[Time delta from previous displayed frame: 0.279231000 seconds]
[Time since reference or first frame: 129.296382000 seconds]
Frame Number: 779
Frame Length: 90 bytes (720 bits)
Capture Length: 90 bytes (720 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ethertype:ip:udp:ntp]
[Coloring Rule Name: UDP]
[Coloring Rule String: udp]
Ethernet II, Src: Apple_a2:57:7b (a8:8e:24:a2:57:7b), Dst:
Actionte_1a:57:9e (00:26:b8:1a:57:9e)
Internet Protocol Version 4, Src: 192.168.1.10, Dst: 17.253.26.253
User Datagram Protocol, Src Port: 123, Dst Port: 123
Network Time Protocol (NTP Version 4, client)
Flags: 0x23, Leap Indicator: no warning, Version number: NTP Version 4,
Mode: client
Peer Clock Stratum: secondary reference (2)
Peer Polling Interval: 6 (64 sec)
Peer Clock Precision: 0.000001 sec
Root Delay: 0.0334 sec
Root Dispersion: 0.0335 sec
Reference ID: 17.253.26.253
Reference Timestamp: Jan 14, 2017 18:20:38.646497000 UTC
Origin Timestamp: Jan 1, 1970 00:00:00.000000000 UTC
Receive Timestamp: Jan 1, 1970 00:00:00.000000000 UTC
Transmit Timestamp: Jan 14, 2017 18:22:46.628854000 UTC
Frame 780: 90 bytes on wire (720 bits), 90 bytes captured (720 bits) on
interface 0
Interface id: 0 (en1)
Encapsulation type: Ethernet (1)
Arrival Time: Jan 14, 2017 10:22:46.663003000 PST
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1484418166.663003000 seconds
[Time delta from previous captured frame: 0.034008000 seconds]
[Time delta from previous displayed frame: 0.034008000 seconds]
[Time since reference or first frame: 129.330390000 seconds]
Frame Number: 780
Frame Length: 90 bytes (720 bits)
Capture Length: 90 bytes (720 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ethertype:ip:udp:ntp]
[Coloring Rule Name: UDP]
[Coloring Rule String: udp]
Ethernet II, Src: Actionte_1a:57:9e (00:26:b8:1a:57:9e), Dst:
Apple_a2:57:7b (a8:8e:24:a2:57:7b)
Internet Protocol Version 4, Src: 17.253.26.253, Dst: 192.168.1.10
User Datagram Protocol, Src Port: 123, Dst Port: 123
Network Time Protocol (NTP Version 4, server)
Flags: 0x24, Leap Indicator: no warning, Version number: NTP Version 4,
Mode: server
Peer Clock Stratum: primary reference (1)
Peer Polling Interval: 6 (64 sec)
Peer Clock Precision: 0.000002 sec
Root Delay: 0.0000 sec
Root Dispersion: 0.0011 sec
Reference ID: Unidentified reference source 'GPSs'
Reference Timestamp: Jan 14, 2017 18:22:40.409336000 UTC
Origin Timestamp: Jan 14, 2017 18:22:46.628854000 UTC
Receive Timestamp: Jan 14, 2017 18:22:46.637396000 UTC
Transmit Timestamp: Jan 14, 2017 18:22:46.637419000 UTC
On Sat, Jan 14, 2017 at 10:55 AM, Bob Camp <kb...@n1k.org> wrote:
> Hi
>
> The issue with using Wireshark is that it still is looking at a ping. It
> may tag the
> event to one more digit, but all of the earlier mentioned issues with
> pings are
> still there. Simply put, they aren’t the greatest thing for testing timing.
>
> Bob
>
>
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