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Questions tagged [latency]

Latency is the time period between a signal being sent and a signal being received

Latency is the time period between a signal being sent and a signal being received. In computer networking this can be the time between a sending of a packet and receiving of a packet.

To illustrate we can use the ping command:

PING google.be (173.194.66.94) 56(84) bytes of data.
64 bytes from google.be (173.194.66.94): icmp_req=1 ttl=47 time=76.6 ms
64 bytes from google.be (173.194.66.94): icmp_req=2 ttl=47 time=74.8 ms
64 bytes from google.be (173.194.66.94): icmp_req=3 ttl=47 time=79.6 ms

The latency here is 76.6 ms.

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Best practices on lowering latency between two endpoints

I would like to know what tools or what kind of calculation should be made in order to find the lower latency possible between two points physically distant. For example: Ping time from Europe to South America is 300ms Ping time from USA to South…
caruizdiaz
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Effect of latency on page load

What effect can a latency of 100 ms have on a page load time? If a 100 KB file is served from two locations with latencies of 100ms and 200ms respectively, will the difference in load time be just 100ms, or will the second request take double the…
Joyce Babu
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Low Latency for Google compared to servers located with in my country

When i ping google.co.in its showing 11.1 ms as average ping www.google.co.in PING www.google.co.in (173.194.36.63) 56(84) bytes of data. 64 bytes from bom04s02-in-f31.1e100.net (173.194.36.63): icmp_req=1 ttl=58 time=11.1 ms 64 bytes from…
kevin
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Can VPNs reduce latency?

I've found a common subject in forums asking about using VPNs to reduce latencies between the gamers and the game servers. I've even found some blog posts confirming this. From my understanding, using a VPN shouldn't reduce latency at all, unless…
Vinko Vrsalovic
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Why my server request takes 28 Second to get response?

I have a Wordpress website on a Godaddy server having at http://kerala.letmeshare.org. When I request to get this website this takes almost 28 sec to get reply. Because of this I made a complete caching on both client side and server side. This…
Abin Manathoor Devasia
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Extremely high apache 2 initial response time, no system load

I've noticed recently that a VPS that I administrate has some strange Apache behaviour. Essentially, any HTTP request hangs for about a second before it is actually served. Output from ab shows something like this: $ ab -n 10 -c 1…
kestrel
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Raid 1 and Latency

I am aware that RAID comes with certain write penalties, etc and that varies at different levels. I am trying to figure out how latency is affected in RAID 1. From my SAN, I can look at the number of writes, reads, bytes, and latency in individual…
sqlbuzz
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How do I calculate the ethernet NIC-to-NIC time to send a MTU packet (1500 bytes)? (OS-excluded)

I understand it will depend on the speed of the ethernet 10 Mbit to 100 Gbit. Given an ethernet speed, how do I calculate the time spend in the wire from NIC-to-NIC? I am assuming here that the machines are in the same room, not across the country…
chrisapotek
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Adjust drive latency/lag on Server 2008 server with an array?

Got a 2008 server in production , which currently has "one" disc. (Actually a SAS array, presented as a single disc to the OS.) This "disc" is partitioned into a few sections, with some free space left over. Someone has the app on the server…
j2k4j
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What is a "Latency Outage"?

I'm one of many customers of Windstream, the only internet provider in my area, and just after having hit the 1-year mark of being a customer, my 10M internet connection became about a 512k connection. I occasionally get my actual 10M speed, but…
Nathan Wheeler
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Why do these ipfw delayed pipes have no effect?

I'm on OSX 10.7.5 and am attempting to add some latency to the connection to my personal domain with ipfw, using this article as a guide. Normal latency: > ping -c5 troutwine.us PING troutwine.us (198.101.227.131):…
troutwine
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High latency issue for web service call from amazon aws ec2 to local server

We have a legacy web application that is running in our data center on premises located in Houston. We have a developed a new .net 4 based web application in order to provide new features to customers. The new web application is hosted in amazon aws…
SibzTer
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What exactly is cut-through latency?

This switch datasheet specifies that the "cut-through latency" is 300ns. What exactly does "cut-through latency" mean? Is it: The difference in time between a packet's head entry and that packet's tail exit? The difference in time between a…
Randomblue
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Is this a latency issue or something else?

I have what I think may be a latency problem. I have a magento installation on a shared host. I know it's best to run magento on a dedicated server but it's early days and it's a good host. When I bring up the front page and check it in the net tab…
byronyasgur
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Latency and bandwidth limitation(WAN Emulation)

I have a requirement to emulate the impact of a new application on the WAN. The WAN bottleneck is a 65MB dedicated pipe between Australia and the UK. I have a setup to generate the traffic, but to monitor the impact on user experience i need a way…
David Colwell
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