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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Does physical distance affect download speed?
I just had an argument with a colleague of mine and thought I'd just reach out to the experts on this. Here's the scenario. We were using a website that measures your connection's speed. We tested ...
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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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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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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 ...
user58476
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What would cause high latency anytime there is traffic on WAN?
I have a network that has been experiencing slow internet speeds. After a great deal of troubleshooting, I have determined that any streaming content/downloads will cause the latency of WAN traffic to ...
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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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Is daisy chaining switches increasing latency?
This is a general question not related to specific hardware. If we have the following configuration of daisy chained switches:
internet ---- core network ----- switch 1 ----- switch 2 ----- switch 3 -...
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How to find the source of increased latency?
I've got monitoring setup on several devices in our office. The ping response time to small access switches is commonly 1-4ms... As of 3AM this morning, this has sky-rocketed to 300ms on average.
...
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Accurate strategy for measuring point-to-point link performance?
I have a requirement to provide an accurate means to demonstrate line performance over a flat layer2 1Gb point-to-point Ethernet circuit, approx 100 miles apart that seemingly goes through a number of ...
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Do faster segments of a network mean faster flow rate or lower latency?
This is another one of those hypothetical questions. I've been trying to figure out whether or not having a faster 'segment' of a network in between host A and host B will translate into a faster flow ...
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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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Ultra-Fast Querying Using UDP Packets
I am implementing a system where one device on a network queries at a very high frequency (hundreds or thousands of queries per second) through sending a small UDP packet with 8 or so bytes of data. ...
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measure one-way latency/jitter/packet-loss
I'm getting increased latency and StDev due to route congestion and packet loss, but the forward and reverse paths go over distinct networks (e.g. one being init7.net, the other one being he.net), so, ...
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Measuring per-link latency/jitter/packet-loss
I need to measure the latency, jitter and packet-loss per link in a network, as opposed to end-to-end, e.g. like this:
s1-eth0 <--> s2-eth0 (~ 20µs avg. latency, standard derivation 10µs, 57 % ...
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Can you reduce RTT by increasing the bandwidth on a link?
Does increasing the bandwidth on a link from, let's say, 1mb to 30mb reduce the RTT?
I have found one answer saying no. Can someone please explain?
Also, what are the best mechanisms to reduce RTT?
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High latency during downloads
I am having the same issue on my business connection 5Mbps as in another posting on this site. As soon as any computer starts a download the latency on the first hop past our DFG provided by our ISP (...
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Recording latency between a controlled startpoint and uncontrolled endpoint
This might be a very basic troubleshooting question, but it's worth asking to make sure I'm testing things the correct way and interpreting results effectively.
I have a controlled start point (a ...
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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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What is the difference between data rate and latency?
Both attempt to measure the speed of a network. If the data rate is the thing that is commonly measured in Mbps and latency is the thing that is measured in milliseconds, what are their similarities ...
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What is a reasonable latency for a L2 1G leased line between 2 sites, about 420km apart?
We need a dual gigabit connection to one of our customers and for the time being one of the lines has been brought online. The connection is between our DC and the customer's HQ, it's a L2 connection. ...
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Switch Buffer Sizing
What is the relationship between a switches buffer size and the effect it has on latency? I am aware of the bufferbloat issue and understand that buffers that are too large in networks of slower BW (i....
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Network Latency issues with Cisco AP
This question involves network latency as opposed to bandwidth.
I have a small remote office with a single Cisco 881W Integrated Services Router (Ethernet WAN). The WAN modem is an AdTran NetVanta ...
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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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How to reduce latency on ASA 5510 WAN link?
I have a Cisco ASA 5510 connecting our office via 2Mbit/s Internet. When Internet link fills up, latency to a well-connected host on Internet goes from 5-8 ms to 500-800 ms. With ping, it may look ...
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Initial estimated round trip time in the RTT formula
I was reading about Round Trip Time (RTT) and then I came across this formula
EstimatedRTT = 0.9 * PreviousEstimatedRTT + 0.1 * Sample RTT
What is the value of PreviousEstimatedRTT when it is ...
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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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Cisco - MtR alternatives
I trying to establish if there is a function within IOS somewhere that can provide the same results of MTR , i know it can be run from Juniper devices / *Nix & Windows devices.
Goal is to ...
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Latency in P2P Circuit
I have one P2P Circuit from our HQ to a secondary office. the distance between them is approx 2kms. Earlier when the Circuit was delivered at that time we were having an RTT of 3-4ms. It is a 10Mbps ...
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Network latency and network bandwidth correlation
Today I was pinging random websites, and I decided to ping a website, from which I was downloading at the speed of 2mb/s, and the ping(latency) was 10 ms.
My question is, if the answer from the ...
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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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Basic Link Aggregation scenario with high ping latency
Resume: I'm have a really basic network cenario with some new switches that I just bought. After configuring a LAG (without LACP) between them, I started to have ping losses and high latency. I also ...
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Cisco C891F-K9 ISR latency?
What is the multicast routing latency of Cisco C891F-K9 ISR? Please cite references for your answer. I think it's store-forward type and isn't one of the fastest models (given its price!).
I've ...
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How fast can information travel through various media?
I'm working on compiling some information about network latency and designing tests to help our support folks troubleshoot problems. In order to do this, I need some basic information that I don't ...
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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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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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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 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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Transmission Rate in terms of distance
If the transmission rate of a physical link, such as ethernet cable, between a sender and receiver is set to be 100Mbps, does it imply that the receiver will receive 100Mb of data in each second? What ...
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POST duration over https vs ping time? [closed]
I'm trying to get a first-order evaluation of how network latency / Round Trip Time (RTT) T, as characterized by ping time, will affect the duration of consecutive sequential POST requests over an ...
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When should a transparent clock or boundary clock be used when designing a network supporting clock synchronization? [closed]
When designing a network incorporating IEEE-1588 (PTP), packet-delay variation (PDV) is a significant source of timing error. Both boundary clocks (network nodes which act as a slave clock to upstream ...
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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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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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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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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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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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What causes packet loss when using full bandwidth from ISP?
We have a small, local ISP that is having some networking issues and I'm trying to understand the cause to better communicate with their network guys. I work with a number of companies with different ...
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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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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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Loosely speaking, at any given moment, how much of the internet is buffered?
When we ping a major web site, we're roughly measuring the delay between our device and the geographic location of the server that the site has chosen to send us to. It really could be anywhere. but ...
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