Hi,
I am sending audio at 50 kHz sample rate via TCP sink from host A to
other host B. The host B is connected via router in same network. How
can i calculate the time delay from host A to host B via this TCP link.
Best Regards,
SAJJAD SAFDAR
Hi Sajjad,
Try tcping if ping doesn’t do what you want:
http://www.linuxco.de/tcping/tcping.html
Mike
–
Mike J. M0MIK BSc MIET
Email: [email protected]
Web: http://scanoo.com
Hi Sajjad,
Ignore the last message! TCP Traceroute is actually what you are after:
http://michael.toren.net/code/tcptraceroute/
You will need to do a time to live of 1
Mike
–
Mike J. M0MIK BSc MIET
Email: [email protected]
Web: http://scanoo.com
On 04/30/2013 03:40 PM, Sajjad S. wrote:
Hi,
Is it any way to calculate using the MTU size of TCP packet and the
sampling rate, like a mathematical approach using formulas.Best Regards,
SAJJAD SAFDAR
Well, no, because you have to actually measure the delay.
Any real IP network has a number of components, each of which introduces
time-varying latencies.
It’s a meaningless question to ask “what is the delay of a typical TCP
channel”. Because, well, there’s no such thing.
Is your TCP channel across the room on a piece of wire? Does it go
through switches/routers? How many of them?
Are all the elements running at the same notional bit-rate?
What is the current latency of packets from userland, through the
kernel, until they “hit the wire”? That varies both with system
architecture and current system loading factors.
You could probably boil it all down to several different delay
contributions, assign them variables and weighting, and come up with an
equation.
But without estimates for the likely ranges of each parameter, it
won’t tell you anything useful, compared to actually measuring the
channel.
Frequently.
The MTU will only tell you if there is fragmentation. In packet
switched networks, there can be delays for any number of reasons that
are not entirely predictable. For example, assume someone is watching a
video, using VOIP, downloading, etc. These can place heavy load on a
switch, router or hub and saturate buffers delaying your packets and
reducing throughput. Other factors such as QoS or traffic shaping can
alter things. Then you have cosmic rays, bad wires, failing circuitry,
etc. Then on a PC the network stack itself can be a source of delays as
this is implemented in software a dependent on the scheduler and what
else is happening in the machine.
Trying to monitor all this, only places additional load on these systems
a skews your results.
The
best you can do is attempt to define an average and identify the worst
case scenario. Aiming between these two figures will normally provide
you with a robust service that exceeds expectation.
Regards,
Mark McCarron
Date: Tue, 30 Apr 2013 12:40:07 -0700
From: [email protected]
Subject: Re: [Discuss-gnuradio] Calculating the delay of TCP link.
To: [email protected]
Hi,Is it any way to calculate using the MTU size of TCP packet and the
sampling rate, like a mathematical approach using formulas.
Best Regards,SAJJAD SAFDAR
From: Mark McCarron [email protected]
To: Sajjad S. [email protected]
Sent: Tuesday, April 30, 2013 12:33 AM
Subject: RE: [Discuss-gnuradio] Calculating the delay of TCP link.
Calculating delay is complex.
If you just want to know the average time between hosts on an IP
network, then use the Ping command. It has a RTT value in ms. Just
remember that on a packet switched network, this can vary but is
typically under 1ms in a local environment.
Similar delays exist throughout the receive chain and processor, which
are virtually impossible to measure accurately.
Accurate measurements like for radar, or bearings are impossible without
some form of time-stamp at the receiver and that would require an atomic
clock chip.
Regards,
Mark McCarron
Date: Mon, 29 Apr 2013 12:01:57 -0700
From: [email protected]
To: [email protected]
Subject: [Discuss-gnuradio] Calculating the delay of TCP link.
Hi,I am sending audio at 50 kHz sample rate via TCP sink from host A to
other host B. The host B is connected via router in same network. How
can i calculate the time delay from host A to host B via this TCP link.
Best Regards,SAJJAD SAFDAR
Calculating delay is complex.
If you just want to know the average time between hosts on an IP
network, then use the Ping command. It has a RTT value in ms. Just
remember that on a packet switched network, this can vary but is
typically under 1ms in a local environment.
Similar delays exist throughout the receive chain and processor, which
are virtually impossible to measure accurately.
Accurate measurements like for radar, or bearings are impossible without
some form of time-stamp at the receiver and that would require an atomic
clock chip.
Regards,
Mark McCarron
Date: Mon, 29 Apr 2013 12:01:57 -0700
From: [email protected]
To: [email protected]
Subject: [Discuss-gnuradio] Calculating the delay of TCP link.
Hi,I am sending audio at 50 kHz sample rate via TCP sink from host A to
other host B. The host B is connected via router in same network. How
can i calculate the time delay from host A to host B via this TCP link.
Best Regards,SAJJAD SAFDAR
Its not quite that simple and the other factors are not negligible by
any means. The recommended approach would be to download Wireshark,
capture the traffic and analyse it in the Throughput Graph.
You can adapt the Wireshark setup from this:
Regards,
Mark McCarron
Date: Thu, 2 May 2013 11:17:45 -0700
From: [email protected]
Subject: Re: [Discuss-gnuradio] Calculating the delay of TCP link.
To: [email protected]
Actually i want to calculate the delay using the formula like Assuming
all other factors as negligible.Here we have 1500 byte tcp header, which
in bits is 1500*8/50KHz. Here the R is in kHz but to use this formula we
have to have R in Bits per second.
Is my way of calculating is right from this approach or not?
Best Regards,SAJJAD
SAFDAR
From: Mark McCarron [email protected]
To: Sajjad S. [email protected]
Sent: Wednesday, May 1, 2013 12:51 AM
Subject: RE: [Discuss-gnuradio] Calculating the delay of TCP link.
The MTU will only tell you if there is fragmentation. In packet
switched networks, there can be delays for any number of reasons that
are not entirely predictable. For example, assume someone is watching a
video, using VOIP, downloading, etc. These can place heavy load on a
switch, router or hub and saturate buffers delaying your packets and
reducing throughput. Other factors such as QoS or traffic shaping can
alter things. Then you have cosmic rays, bad wires, failing circuitry,
etc. Then on a PC the network stack itself can be a source of delays as
this is implemented in software a dependent on the scheduler and what
else is happening in the machine.
Trying to monitor all this, only places additional load on these systems
a skews your results.
The best you can do is attempt to define an average and identify the
worst case scenario. Aiming between these two figures will normally
provide you with a robust service that exceeds expectation.
Regards,
Mark McCarron
Date: Tue, 30 Apr 2013 12:40:07 -0700
From: [email protected]
Subject: Re: [Discuss-gnuradio] Calculating the delay of TCP link.
To: [email protected]
Hi,Is it any way to calculate using the MTU size of TCP packet and the
sampling rate, like a mathematical approach using formulas.
Best Regards,SAJJAD SAFDAR
From: Mark McCarron
[email protected]
To: Sajjad S. [email protected]
Sent: Tuesday, April 30, 2013 12:33 AM
Subject: RE: [Discuss-gnuradio] Calculating the delay of TCP link.
Calculating delay is complex.
If you just want to know the average time between hosts on an IP
network, then use the Ping command. It has a RTT value in ms. Just
remember that on a packet switched network, this can vary but is
typically under 1ms in a local environment.
Similar delays exist throughout the receive chain and processor, which
are virtually impossible to measure accurately.
Accurate measurements like for radar, or bearings are impossible without
some form of time-stamp at the receiver and that would require an atomic
clock chip.
Regards,
Mark McCarron
Date: Mon, 29 Apr 2013 12:01:57 -0700
From: [email protected]
To: [email protected]
Subject: [Discuss-gnuradio] Calculating the delay of TCP link.
Hi,I am sending audio at 50 kHz sample rate via TCP sink from host A to
other host B. The host B is connected via router in same network. How
can i calculate the time delay from host A to host B via this TCP link.
Best Regards,SAJJAD SAFDAR