Questions tagged [latency]
For questions about network latency. For instance: the propagation of your network traffic, where the transmission medium can be defect or the processing of packets by a network device has slowed down.
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cut-through vs store-and-forward switching
Let's say we have a host A that is sending 1bit of data (I know it is impossible practically) at at rate of 1bps to host B. Host A and Host B are connected via 2 switches. We assume that the ...
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How to solve high ping "spikes" to pfSense when ipSec connections are active?
Background information:
We have latency/freeze problems with our pfSense. To be able to answer the question i will first give some general background information:
We run pfSense V2.6.0 on following ...
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Measuring Latency between my local network hops [closed]
I have to measure the latency in my local network and also between each hop. I used the conventional tools like ping, tracert, pathping etc. But the problem is here these tools have there own protocol ...
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How to benchmark time a packet spend in each OSI layer?
I'm benchmarking latency of sending a TCP packet from a client to a server. The payload of the packet is the nanosecond timestamp (using clock_gettime() on Linux) right before the send() socket ...
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Optimal segment size for store-and-forward switching [closed]
Suppose we are transmitting a file of size X bits from A to B. They are connected to each other with a single switch using store-and-forward switching. Before transmission, A splits the file into ...
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Latency between a churn and congestion event triggered in the TCP code
I am analyzing the time it takes between a churn occurring in the network (e.x. that causes packet drops or delays) and when the congestion event handling codes are triggered in the TCP kernel in the ...
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If TCP packets are pre acknowledged, what happens if packets are dropped?
On a VSat link with 800ms RTT latency and 10mbps bandwidth, that means 1MB bandwidth-delay product (data in flight).
According to this useful (but closed) Q/A, packets are injected on both sides of ...
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T_Latency = T_Propagation + T_Transmit + T_Queue? [duplicate]
I am currently learning about the so-called 'physical layer' of a computer network. The following claim is made:
The latency of a message is the total time for the whole message to arrive:
T_Latency =...
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Network speeds severely impacted by latency [closed]
I'm troubleshooting a situation where clients in far off locations with high latency connections to our network are experiencing severely adverse network transfer speeds.
If I run a speed test from ...
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Why does ping interval affect latency?
The following article on Google Cloud describes measuring latency, and uses ping and netperf.
https://cloud.google.com/blog/products/networking/using-netperf-and-ping-to-measure-network-latency
It ...
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Transmission and propagation delays
I am now working through book "Computer Networking - A Top Down Approach", and there is one question among others after the first chapter:
"Consider two hosts, A and B, connected by a ...
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Will TCP packets smaller than the full bandwidth of its link travel at the same speed?
If I send 5bytes over a 1mbps connection will that travel faster than 500bytes. Or is the latency after propagation going to be constant since the packet is under 1mb?
If you downvote because you ...
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How can the latency value be so low from Singapore to USA (~2ms)?
Here's the ping output from Singapore:
64 bytes from 8.8.8.8: icmp_seq=1 ttl=50 time=1.96 ms
Singapore to 8.8.8.8 = ~2ms
Another ping output:
64 bytes from 23.59.8.146: icmp_seq=81 ttl=44 time=66....
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Copper or Glass for Low Latency?
I'd like to preface the main content of this post with the following: I understand this question may be equally suited to the Physics Stack Exchange, and so I have posted on there as well, but maybe a ...
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TCP Bandwidth and delay guarantees
I was wondering if TCP can provide bandwidth and delay guarantees? Or does it have to implemented on the application layer?
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network slowness troubleshoot
I want some suggestion regarding our network issue:
From our office location to our DC ==> it's ~270msc(office and DC lies in different countries). As, you can already see here latency is the major ...
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Best way to Fast Reconnect TCP with dynamic IP
I am aware of TCP Fast Open, all though, I'm pretty sure it doesn't apply when the IP of the server changes dynamically. Getting the IP of the server quickly isn't the problem.
The problem is that I ...
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Estimate latency between two IP addresses
I would like to estimate what is the latency in sending a packet between two IP addresses.
Let's assume that I have two IP addresses: ip1 and ip2. I can easily ping both ip1 and ip2, and the ping ...
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How to calculate the latency in vehicular network?
I need to calculate the delay in vehicular network V2V and V2I and I define it as the following:
Where L [Bit] the length of data and the transmission rate
where is the distance between vehicle i ...
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Response time of TCP congestion control
I would like to know about the overall latency of the TCP congestion control for adapting to varying network conditions. Specifically, my questions are:
How fast can the system react after a change ...
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Delay, Packet length and transmission rate
Why does the delay in sending a packet from source to destination doesn't depend upon the transmission rate and the packet length? If we look at the delay formula then it is, L/R + D/V.
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Network latencies between opposite ends of the Earth
This is just out of curiosity.
when I pinged domains such as bbc.co.uk and google.com (in California), I get latencies of around 5ms as below:
64 bytes from xx: icmp_seq=0 ttl=55 time=2.940 ms
64 ...
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Can clock synchronization ever be more than guesswork within a certain interval?
Assuming consistent spacial interference, e.g.
The time for packet Z to get from point A to point B will always be
constant.
The time for packet Z to get from point B to point A
will always be ...
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Estimating bandwidth requirements and productivity gain from traffic data
My small office has a 30Mbit/s internet connection, on which two or three people work. We could get twice the bandwidth at a substantial cost.
I imagine a bandwidth upgrade would slightly improve ...
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How to Troubleshoot Network Latency Step by Step
Does anyone have an idea of how to troubleshoot high network latency step by step?
For example, let's say we have a remote office. And all users are from that office are having high latency accessing ...
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Does bridging add delay?
If I use a bridge to perform traffic sniffing like man in the middle will the bridge add a delay? And what word should I use delay or latency?
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How to measure time a request takes between two machines?
I need to calculate the time it takes between:
a request sent from a machine
the request is received at another machine
I can do it by logging, but the clocks at these 2 machines are possible have a ...
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Serialization and serialization times in 40G/10G and 100G/25G Ethernet
I've recently been involved in discussions about lowest-latency requirements for a Leaf/Spine (or CLOS) network to host an OpenStack platform.
System architects are striving for the lowest possible ...
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Weird packet lost. Looking for some input
Like me start by saying I'm not an network expert but this situation got me scratching my head and you guys might be able to help.
The infrastructure is 4 switches (Dell 2848). 2 For the LAN and 2 ...
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What is the relationship between throughput and latency
Looking at the structure of a TCP packet, such as discussed here: What is the internal structure of a mobile phone call packet/datagram?, this indicates that a TCP packet size is 192 bytes excluding ...
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What are the differences between TCP iRTT and ICMP Ping?
I’m attempting to estimate latency between my PC and any servers/clients it interacts with. I don’t want to use Ping for various reasons (requires both ends to allow it, would require additional ...
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What's the difference between `Latency` and `Round Trip Time`?
Golang community provide a HTTP/2 demo website to compare the performance between HTTP 1.1 and HTTP/2.
We can choose different latency, e.g. 0s latency, 30 ms latency, 200ms latency.
Is latency a ...
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are the RTTs additive?
By using the ping,
I calculate the RTT between A and B.
I calculate the RTT between A and C.
I calculate the RTT between C and B.
Is it possible to compare the RTT of topological link A->B with the ...
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does the DSL distance really add more latency
I've been using dsl internet for quite a while and having a ping from Algeria to France of about 90 ms , after trying to ping some locations in Algeria , i am getting about 50 ms, ping to my gateway ...
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High Jitter and Data Loss on Cisco Meraki Z1
Our office is running a Cisco Meraki Z1 Security Appliance and recently (March 5th) the internet has been dropping out intermittently. The appliance remains online but the internet either doesn't work ...
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How to measure latency and udp-jitter from the end-server [closed]
Is there anyway to monitor a latency and jitter from SLA Router to EndClient(Linux Server).
I have tried to use IP SLA with UDP Jitter but it didn't work.
Diagram
SLA-Router -------> Linux ...
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Is RTT the same as round-trip propagation time?
As far as I know:
(1) Latency (τ) = transmission delay + propagation delay + queuing delay + processing delay
(2) Round-trip time (RTT) is two times the latency (assuming the same latency both ways)
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Why can insufficient bandwidth reduce latency?
In this article, it is stated that latency does not affect bandwidth, but insufficient bandwidth can reduce latency.
Can someone explain me the latter part of the statement? How would insufficient ...
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What is the latency of IP over Infiniband compare with 10Gbps fibre network?
What is the latency of IP over Infiniband compare with 10Gbps fibre network?
10Gbps network is something like a Solarflare low latency NIC card. How well does IP over IB perform not just throughput ...
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What is the value of EstimatedRTT at first time?
Although this question might be marked as duplicated! I'm asking again because other question's answers like this couldn't help me. So please consider the case and don't mark it as duplicate and ...
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Dynamically generate OSPF/BGP routes based on Internet latency
Scenario
Three Offices with 2 ISPs each - utilizing static routing to the ISP. Each office has a VPN and leased point-to-point circuits connecting the offices in a ring. A VPN is also connecting the ...
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What are the concerns other than latency for network tuning?
Everywhere I keep finding "to achieve low latency" or "latency is of concern", do this!
So, I don't really get what are the other concerns other than latency. I mean who doesn't want low latency? Or ...
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How can I determinte the reason of server-to-server latency in my network? [closed]
We have a proplem with server-to-server latency. How can I determine the reason for it? These servers are connected to different Cisco switches. Althought the reason for this problem might not be ...
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Using the value of RTT to estimate the latency
Generally speaking, we can calculate the packet delivery time using this formula, Wikipedia:
Latency = Transmission delay + Propagation delay + queuing delay + processing delay
My question is: Is it ...
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Latency of AOC vs passive DAC
Long time ago I heard from friend that on really short distance using optical links makes no much sense because comparing to passive connection optical interfaces introduce another layer of hardware ...
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How to measure the firewall latency?
I want to make a lab experiment to measure the firewall (a hardware) latency. This firewall can do Deep Packet Inspection (DPI) on some industrial protocols (you can consider as TCP payload inspection)...
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How to find out TCP/UDP latency of your network? [closed]
Many people often suggest you to use ping command to find out your network latency. But it is false and a myth you often find in articles on Internet.
ICMP ping was never designed to find out latency ...
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Measure latency and other statistics by comparing PCAPs
I need to measure certain statistics, such as latency, packet delay, and jitter. Would it be possible to measure these statistics between 2 nodes by sniffing traffic on both ends and then comparing ...
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Cisco VLAN configurations with WAP - Poor performance
We've recently applied a new modification to our network config.
Separating two SSIDs into a guest \ corporate split config.
All of the VLAN and DHCP scopes are functioning in the way it was designed ...
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What's the difference among bandwidth, ping, ping rate and latency?
All these terms are quite related but I couldn't understand when to use which. I often hear that some networks have low bandwidth and high ping rate for online gaming. I thought they might be ...
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