Why is pinger so slow

Project Management. Resources Blog Articles. Menu Help Create Join Login. Brought to you by: basildane. Pinger too slow. Forum: Help. Creator: Nobody Knows. Created: Updated: Nobody Knows - They use in pseudo code : Take the average round trip latency in milliseconds , add round trip jitter, but double the impact to latency then add 10 for protocol latencies in milliseconds. Anything over that gets a much more agressive deduction.

G "Network contribution to transaction time". Strictly speaking the losses are the TCP losses which are not necessarily identical to the ping losses e. However, especially for lower performance links it is a reasonable estimator. See Error performance objective for GbE. An improved form of the above equation can be found in: Modeling TCP throughput: A simple model and its empirical validation by J.

Padhye, V. Firoiu, D. Townsley and J. Kurose, in Proc. Communications Architectures and Protocols Aug. Directness values close to one mean the path between the hosts follows a roughly great circle route.

Values much smaller than 1 mean the path is very indirect. The derivation of directness coefficient Directivity based on the minimu RTT is given here. In the case of the VTrace visual traceroute , the difference between hop distance and end-to-end distance can provide an estimate of the Directivity. The end-to-end distance is the great circle path distance between source and destination, where as the total hop distance is the sum of great circle distances between all consecutive hops.

Access to data The raw ping data is publicly accessible, see Accessing the PingER data for how to get the data and the format. The summarized data is also available from the web in Excel tab-separated-value. To the left is an example showing several hosts in black all being unreachable around 12 noon. Last Days plots: Long term graphs showing the response time, packet loss and unreachability for the last days can also indicate whether a service is getting worse or better.

This tabular data can be exported to Excel and charts made of the long term ping packet loss performance. Quiescent Network Frequency When we get a zero packet loss sample a sample refers to a set of n pings , we refer to the network as being quiescent or non-busy.

We can then measure the percentage frequency of how often the network was found to be quiescent. A high percentage is an indication of a good quiescent or non-heavily loaded network. This way of representing teh loss is similar in intent to the phone metric of error-free seconds. The Quiescent Network Frequency table shows the percentage frequency of the samples where a sample is a set of 10 byte pings that measured zero packet loss.

The samples included in each percentage reported are all the samples for each site for each month i. Jitter , see also Jitter , The short term variability or "jitter" of the response time is very important for real-time applications such as telephony.

Web browsing and mail are fairly resistent to jitter, but any kind of streaming media voice, video, music is quite suceptible to jitter.

Jitter is a symptom that there is congestion, or not enough bandwidt to handle the traffic. The jitter specifies the length of the VoIP codec de-jitter buffer to prevent over- or under-flow. One method requires injecting packets at regular intervals into the network and measuring the variability in the arrival time.

Note that when calculating dR the packets do not have to be adjacent. Both of the above distributions can be seen to be non-Gaussian which is why we use the IQR instead of the standard deviation as the measure of "jitter".

They vary by two orders of magntitude over the day. We have also obtained a measure of the jitter by taking the absolute value dR , i. This is sometimes referred to as the "moving range method" see Statistical Design and Analysis of Experiments , Robert L.

Mason, Richard F. Guest and James L. It is also used in RFC as the definition of jitter RFC has another definition of jitter for real time use and calculation See the Histogram of the moving range for an example. In this figure, the magenta line is the cumulative total, the blue line is an exponentail fit to the data, and the green line is a power series fit to the data. Note that all 3 of the charts in this section on jitter are representations of identical data.

A rough schematic is shown to the right. The gateway encodes, compresses etc. With no competing traffic on the link, the call connects and the conversation proceeds normally with good quality. At this stage, the VoIP connection is broken and no further connections can be made. In this setup voice connections can again be made and the conversation is again of good quality. The 2 is since the packet has to go out and come back.

Another way of looking at the ratios is that numbers near 1 indicate that average performance is close to the best performance. Numbers not close to 1 are typically caused by large variations in ping time between work hours and non-work hours, see for example the UCD ping response for Oct 3, for an example of the diurnal variations.

Some examples of ping predictability scatter plots for various parts of the Internet as measured from SLAC for July and March can be seen below. Such a plot for a few N. American nodes for July and March shows big changes, in all cases being for the worse more recent points are more to the lower left of the plot.

Unpredictability One can also calculate the distance of each predictability point from the coordinate 1,1. We normalize to a maximum value of 1 by dividing the distance by sqrt 2. I refer to this as the ping unpredictability , since it gives a percentage indicator of the unpredictability of the ping performance. Reachability By looking at the ping data to identify 30 minute periods when no ping responses were received from a given host, one can identify when the host was down.

The reachability is very dependent on the remote host, for example if the remote host is renamed or removed, the host will appear unreachable yet there may be nothing wrong with the network. Thus before using this data to provide long term network trends the data should be carefully scrubbed for non-network effects. Examples of ping reachability and Down reports are available. One can also measure the frequency of outage lengths using active probes and noting the time duration for which sequential probes do not get through.

Out of Order packets PingER uses a very simple algorithm for identifying and reporting out of order packets. For each sample of 10 packets, it looks to see if the sequence numbers of the responses are received in the same order as the requests were sent. If not than that sample is marked as having one or more out of order responses. For a given interval say a month the value reported for ou of order is the fraction of samples that were marked with out of order ping responses.

Since the ping packets are sent at one second intervals it is expected that the fraction of out of order samples will be very small, and may be worth investigating whenever it is not. The IP address pinged may be a broadcast address. A router believes it has two routes by which it can reach the end host and presumably mistakenly forwards the ICMP echo requests by both routes, thus the end host sees two echo requests and responds twice.

There maybe two or more non-routed paths to the end host and each request is forwarded by more than one path. A misbehaving NAT box. Some tests that may help include: Pinging the routers along the route to see if any of them respond with duplicates. Capture the ping packets and look to see if all the packets are returned from the same Ethernet address.

An idea of the prvalence of duplicate ping packets comes from PingER measurements on March 31st to hosts in over countries. Of these hosts 15 responded with duplicate pings. For 13 of the 15 hosts it occured on both and Byte pings. Out of 10 pings sent 6 hosts had 1 ping duplicated, 5 had 2 pings duplicated, 2 had 4 pings duplicated, 1 had 3 pings duplicated and 1 returned 12 pings for each ping sent. PingER simply reports wheter there were duplicates or not.

The number received may depend on the ping command options. One option will send a given number of pings until it receives that many back or times out. Another option will send 10 pings and wait or time out until they are received. So the metric value may also depend on the ping command. Combination of all ping measures One can put together a plot of all the above ping measures loss, response, unreachability and unpredictability to try and show the combination of measurements for a set of hosts for a given time period.

The plot below for March , , groups the hosts into logical groups ESnet, N. America West, In the above plot, the loss and response time are measured during SLAC prime time 7am - 7pm, weekdays , the other measures are for all the time. The response time is plotted as a blue line on a log axis, labelled to the right, and is the round trip time for byte ping payload packets.

A host is deemed unreachable at a 30 minute interval if it did not respond to any of the 21 pings made at that 30 minute interval. The host unpredictability is plotted in green here as a negative value, can range from 0 totally unpredictable to 1 highly predictable and is a measure of the variability of the ping response time and loss during each 24 hour day.

It is defined in more detail in Ping Unpredictability. If you know of other possible solutions, we look forward to receiving a message from you at the end of this article. So, we hope the tips and tricks were helpful and the Pinger Calling App download works again quickly and without any problems.

By the way there may be other problems and errors that you may find in the overview of all Pinger Calling App problems. If you continue to have problems and Pinger Calling App is still loading slowly, we look forward to hearing from you.

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