How to eliminate the delay in NTP synchronization?
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Currently, I am doing a NTP time synchronization between two ubuntu pcs connected by a LAN cable. After I finish the setup, I find that the delay is around 0.170s (170ms), which is not acceptable since I expect a delay less than 30ms. What could be the reasons causing the delay? And how could I solve it?
ntp
asked Apr 24 at 8:11
Teddy_NTU
132
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up vote
2
down vote
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Currently, I am doing a NTP time synchronization between two ubuntu pcs connected by a LAN cable. After I finish the setup, I find that the delay is around 0.170s (170ms), which is not acceptable since I expect a delay less than 30ms. What could be the reasons causing the delay? And how could I solve it?
ntp
asked Apr 24 at 8:11
Teddy_NTU
132
how do you measure this delay?
– pim
Apr 24 at 9:17
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
Currently, I am doing a NTP time synchronization between two ubuntu pcs connected by a LAN cable. After I finish the setup, I find that the delay is around 0.170s (170ms), which is not acceptable since I expect a delay less than 30ms. What could be the reasons causing the delay? And how could I solve it?
ntp
asked Apr 24 at 8:11
Teddy_NTU
132
Currently, I am doing a NTP time synchronization between two ubuntu pcs connected by a LAN cable. After I finish the setup, I find that the delay is around 0.170s (170ms), which is not acceptable since I expect a delay less than 30ms. What could be the reasons causing the delay? And how could I solve it?
ntp
asked Apr 24 at 8:11
Teddy_NTU
132
asked Apr 24 at 8:11
Teddy_NTU
132
asked Apr 24 at 8:11
Teddy_NTU
132
asked Apr 24 at 8:11
Teddy_NTU
132
132
how do you measure this delay?
– pim
Apr 24 at 9:17
add a comment |Â
how do you measure this delay?
– pim
Apr 24 at 9:17
how do you measure this delay?
– pim
Apr 24 at 9:17
how do you measure this delay?
– pim
Apr 24 at 9:17
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
0
down vote
accepted
I assume you use ntpq, which gives delay in milliseconds. 0.170 in the delay column of ntpq -p means a delay of 0.170ms, not 0.170 seconds.
0.170ms is a reasonable delay over a switched ethernet. 170ms does not make a lot of sense.
Explanation of the output is given in the ntpq documentation:
peers
Obtains a current list peers of the server, along with a summary of each peer's state. Summary information includes the address of the remote peer, the reference ID (0.0.0.0 if this is unknown), the stratum of the remote peer, the type of the peer (local, unicast, multicast or broadcast), when the last packet was received, the polling interval, in seconds, the reachability register, in octal, and the current estimated delay, offset and dispersion of the peer, all in milliseconds. The character at the left margin of each line shows the synchronization status of the association and is a valuable diagnostic tool. The encoding and meaning of this character, called the tally code, is given later in this page.
My formatting.
answered Apr 24 at 10:16
vidarlo
7,12342140
1
Oh my god. I think you are correct. I thought the unit of delay in ntpq -p is in seconds. Thank you very much.
– Teddy_NTU
Apr 25 at 5:57
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
accepted
I assume you use ntpq, which gives delay in milliseconds. 0.170 in the delay column of ntpq -p means a delay of 0.170ms, not 0.170 seconds.
0.170ms is a reasonable delay over a switched ethernet. 170ms does not make a lot of sense.
Explanation of the output is given in the ntpq documentation:
peers
Obtains a current list peers of the server, along with a summary of each peer's state. Summary information includes the address of the remote peer, the reference ID (0.0.0.0 if this is unknown), the stratum of the remote peer, the type of the peer (local, unicast, multicast or broadcast), when the last packet was received, the polling interval, in seconds, the reachability register, in octal, and the current estimated delay, offset and dispersion of the peer, all in milliseconds. The character at the left margin of each line shows the synchronization status of the association and is a valuable diagnostic tool. The encoding and meaning of this character, called the tally code, is given later in this page.
My formatting.
answered Apr 24 at 10:16
vidarlo
7,12342140
1
Oh my god. I think you are correct. I thought the unit of delay in ntpq -p is in seconds. Thank you very much.
– Teddy_NTU
Apr 25 at 5:57
add a comment |Â
up vote
0
down vote
accepted
I assume you use ntpq, which gives delay in milliseconds. 0.170 in the delay column of ntpq -p means a delay of 0.170ms, not 0.170 seconds.
0.170ms is a reasonable delay over a switched ethernet. 170ms does not make a lot of sense.
Explanation of the output is given in the ntpq documentation:
peers
Obtains a current list peers of the server, along with a summary of each peer's state. Summary information includes the address of the remote peer, the reference ID (0.0.0.0 if this is unknown), the stratum of the remote peer, the type of the peer (local, unicast, multicast or broadcast), when the last packet was received, the polling interval, in seconds, the reachability register, in octal, and the current estimated delay, offset and dispersion of the peer, all in milliseconds. The character at the left margin of each line shows the synchronization status of the association and is a valuable diagnostic tool. The encoding and meaning of this character, called the tally code, is given later in this page.
My formatting.
answered Apr 24 at 10:16
vidarlo
7,12342140
1
Oh my god. I think you are correct. I thought the unit of delay in ntpq -p is in seconds. Thank you very much.
– Teddy_NTU
Apr 25 at 5:57
add a comment |Â
up vote
0
down vote
accepted
up vote
0
down vote
accepted
I assume you use ntpq, which gives delay in milliseconds. 0.170 in the delay column of ntpq -p means a delay of 0.170ms, not 0.170 seconds.
0.170ms is a reasonable delay over a switched ethernet. 170ms does not make a lot of sense.
Explanation of the output is given in the ntpq documentation:
peers
Obtains a current list peers of the server, along with a summary of each peer's state. Summary information includes the address of the remote peer, the reference ID (0.0.0.0 if this is unknown), the stratum of the remote peer, the type of the peer (local, unicast, multicast or broadcast), when the last packet was received, the polling interval, in seconds, the reachability register, in octal, and the current estimated delay, offset and dispersion of the peer, all in milliseconds. The character at the left margin of each line shows the synchronization status of the association and is a valuable diagnostic tool. The encoding and meaning of this character, called the tally code, is given later in this page.
My formatting.
answered Apr 24 at 10:16
vidarlo
7,12342140
I assume you use ntpq, which gives delay in milliseconds. 0.170 in the delay column of ntpq -p means a delay of 0.170ms, not 0.170 seconds.
0.170ms is a reasonable delay over a switched ethernet. 170ms does not make a lot of sense.
Explanation of the output is given in the ntpq documentation:
peers
Obtains a current list peers of the server, along with a summary of each peer's state. Summary information includes the address of the remote peer, the reference ID (0.0.0.0 if this is unknown), the stratum of the remote peer, the type of the peer (local, unicast, multicast or broadcast), when the last packet was received, the polling interval, in seconds, the reachability register, in octal, and the current estimated delay, offset and dispersion of the peer, all in milliseconds. The character at the left margin of each line shows the synchronization status of the association and is a valuable diagnostic tool. The encoding and meaning of this character, called the tally code, is given later in this page.
My formatting.
answered Apr 24 at 10:16
vidarlo
7,12342140
answered Apr 24 at 10:16
vidarlo
7,12342140
answered Apr 24 at 10:16
vidarlo
7,12342140
answered Apr 24 at 10:16
vidarlo
7,12342140
7,12342140
1
Oh my god. I think you are correct. I thought the unit of delay in ntpq -p is in seconds. Thank you very much.
– Teddy_NTU
Apr 25 at 5:57
add a comment |Â
1
Oh my god. I think you are correct. I thought the unit of delay in ntpq -p is in seconds. Thank you very much.
– Teddy_NTU
Apr 25 at 5:57
1
1
Oh my god. I think you are correct. I thought the unit of delay in ntpq -p is in seconds. Thank you very much.
– Teddy_NTU
Apr 25 at 5:57
Oh my god. I think you are correct. I thought the unit of delay in ntpq -p is in seconds. Thank you very much.
– Teddy_NTU
Apr 25 at 5:57
add a comment |Â
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how do you measure this delay?
– pim
Apr 24 at 9:17