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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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Is it bad that latency for our internal LAN varies greatly within the 15 - 40 ms range?

I've always thought the "typical" latency for a small office wired Ethernet network would be <5 ms. However, pinging the default gateway yields an average of 14 ms, and any host is around 30 ms. What could be the cause of these poor latencies? Does…
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Cached content causing a huge number of 404 errors, too many connections

My site has been largely unresponsive for three days due to a large amount of traffic. A JavaScript element on the page regularly requested images from the server, and the number of connections became a problem as people left their browser windows…
Peter
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Network communication between dedicated web and database server

We're at the juncture (I can even say, right time) that we need to separate our database server apart from our application web server. This we arrived at after careful & thorough monitoring of the server (load average, CPU usage, etc.) itself. When…
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SONET ADM Latency

Is there published documentation on best-case and worst-case latency added by SONET ADM equipment? Specifically I'm looking for the latency I could expect to be added to an OC-3 piped through these pieces of gear: Fujitsu FlashWave 4500 MSPP Cienna…
James Cape
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ping6 overhead compared to ping overhead

I am testing IPv6 latency from a Linux box, and I noticed this weird difference between IPv4 ping and IPv6 ping: # ping -n -A -q -c 500 speedtest.steffann.nl PING speedtest.steffann.nl (10.3.10.20) 56(84) bytes of data. --- speedtest.steffann.nl…
Sander Steffann
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Remote Desktop Software with low latency

I am searching for a remote desktop software (Linux/Windows/Mac) which has a very low latency between input+output (lower then 1 sec). Some VNC (UltraVNC, RealVNC) solutions have a latency of 1-2 seconds - even if connected directly over a switch.…
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Strange server connection issue between two networks

I have two sites connected with 2 encryption devices on either side. Each site has a single flat switch connected to the encrption device on each side. Site A has servers. Site B has workstations. Systems are directly plugged into the switch at…
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How to optimize Windows Server 2008 TCP Latency?

I 'm designing a distributed system and I deploy it on 1Gb cluster of Windows Server 2008 R2 But I have issue with the latency, the normal Ping takes 0.270ms and I believe this is too much, since all the machines connected locally via one 1Gbs…
Haytham
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Troubleshooting intermittent network "drops"

We do most of our work on colocated servers in a datacenter over SSH. This means that we're connected to the boxes almost all day, 5 days a week. Intermittently, we'll see a lag between typing on the keyboard, and having the contents echo'd back to…
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How much latency does raid 5 add to transfers?

Your bandwidth/throughput should go up with raid 5, but you will take a bit of hit in latency after you over run the cache, since you need to calculate the parity. Has anybody done a latency test using 1 HD vs 3 HD in raid 5? I am very interested…
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VPN traffic is quicker than across the internet with open ports

I have a site to site VPN link and ports open on its public IP for a service. I can connect up to the remote server using the private Ip address of the remote subnet across the VPN and it takes about 150ms. If however I go across the internet and to…
Gavin Will
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Which hosts have low latency across United States and Europe?

I'm looking for some information on web hosts that have low latency (<100ms) to both the United States and Europe. The host can be in either the United States or Europe. Latency is most important to the United States, United Kingdom, the…
Joost
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How can I troubleshoot excessive latency between client and server?

On a large private network there seems to be excessive latency between two boxes which I control. This is stopping the server providing a web service to the client as its causing timeouts. Here's a slow running request logged in Charles Timing …
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Mixing ram, what can I add that wont cause trouble?

Hey I have some of this this in a home server and wanted to throw another couple gigs in there. The problem is that its out of production, so I don't know what I can mix it with. I havent found anything sofar that matches CAS and voltage. This is cl…
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use of tcp_delack_min on redhat linux (kernel 2.6.18)

we're moving from Solaris to Redhat Linux, and trying to duplicate our low-latency setup, that, on solaris, includes the ndd settings related to TCP NO DELAY, and NAGLE ALGORITHM. I got the impression that those parameters are not all configurable…
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