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

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Diagnose cause of long running requests in IIS 7.0

We are running an ASP.NET web application on IIS 7.0, Windows Server 2008 R2, with SQL Server 2008 R2 for DB. On weekends, when the traffic is high, the request queue length in the IIS servers ...
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3answers
4k views

What can make windows fileshares slow without affecting ping latency, remote desktop, cpu usage or disk access?

I've got a server named Babylon. It's running Windows Server 2003 SP2 and lives in the midwest. I can ping Babylon from remote machines in the same building by hostname and IP. The latency is ...
0
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1answer
166 views

What settings should I modify to tune a Linux server for very small yet very high packet rate UDP receive loads?

I am tuning a server that needs to handle small (average of about 50 bytes) UDP packets. The average packet rate is approximately 100,000 packets/second. The data is very burst and can sometimes burst ...
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1answer
477 views

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) ...
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3answers
270 views

Monitoring Internet latency

I've been using smokeping to monitor internet latency (for early problem detection) at 8.8.8.8 for several months. On Friday the average latency went from 12ms to 55ms and has been at the 55ms plateau ...
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2answers
161 views

Set up server far away from target audience? [closed]

I live in Canada, and I want to move out of online web hosting and host stuff on my own server. The problem is, my website caters to a huge amount of US traffic, about 90 percent of traffic is US. ...
2
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2answers
96 views

QoS switch messing with local http traffic?

WE just moved our rack to a datacenter in the building. In our rack is a blade running centos and apache for intranet stuff. When we moved to the DC, we essentially extended our LAN there via adding a ...
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2answers
3k views

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 ...
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2answers
1k views

Ping with long delay but short reported time

What does it mean when a ping reports a reasonable time (~10ms) but actually takes quite a long wall clock time (~15 seconds)? (Additionally, passing the -U option for "full user-to-user latency" has ...
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1answer
119 views

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. ...
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1answer
602 views

iproute: disable “tc” command

I'm after running this command to simulate a network latency of 500ms with 100ms std deviation: tc qdisc add dev eth2 root netem delay 500ms 100ms Trouble is, I forget how to cancel this command! My ...
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6answers
8k views

Intermittent high ping/latency problem

I have been working with my ISP (which is a WISP, actually Fixed Broadband Wireless) trying to figure out why I intermittently get high latency. The latency is detectable in online games and other ...
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7answers
13k views

Troubleshooting latency spikes on ESXi NFS datastores

I'm experiencing fsync latencies of around five seconds on NFS datastores in ESXi, triggered by certain VMs. I suspect this might be caused by VMs using NCQ/TCQ, as this does not happen with virtual ...
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3answers
1k views

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 ...
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2answers
2k views

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 ...
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2answers
226 views

Networking Hardware Suggestions For Low-Latency Networking

We've come to the stage of our project where we want to take the software to the next level, generally response times of 20µs or less. Software wise its as good as it gets (though there's room for a ...
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4answers
4k views

What kind of latency numbers are reasonable for a corporate network?

I am a software developer and I sometimes want to work from home but to write code over on a VPN is just tortuously slow. I have tried several different things to try and make it more reasonable. On ...
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1answer
1k views

what is the latency for an 8K transfer of Fibre Channel? (NFS vs FC) [closed]

I've heard it said that a 512byte data transfer over fibre channel is 10us so would an 8k (16x the data) take 160us? or is much of that 10us one time transmit overhead? I'm interested in comparing ...
3
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1answer
275 views

different ACK behaviors (slowing down throughput?)

I'm running netio (http://freshmeat.net/projects/netio/) on one machine (opensolaris) and contacting two different Linux machines (both on 2.6.18-128.el5 ), machine A and machine B. Machine A has a ...
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1answer
66 views

Measuring latency to a firewalled server

The firewall in front of this server is blocking ping requests. Is is still possible to measure latency to this system? If so, how?
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5answers
318 views

Measuring Site to Site Latency for Video Conferencing

We are currently looking at doing some international video conferencing, and before we go ahead and buy a system we need to measure Site to Site Latency & bandwidth objectively. I can't see any ...
0
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1answer
418 views

Slow upload to Server 2008 DC, Downloads work as expected

I have a Windows Server 2008 Domain Controller that I run as a do-it-all server. It has a GbE connection to the network and to every machine on the network. Downloads from the server file shares work ...
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2answers
15k views

What is best tool to measure network latency?

How do you measure network latency in Windows ? I know ping as one of the tool. Can Windows Performance monitor do it ? Any ideas which counters should I add to measure it. This is for SharePoint ...
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1answer
2k views

low latency TCP settings on windows 2008 R2

I am running a third party software on a W2008 server. This client connects to a server via TCP. The average ping times between the two are 1ms. However, when I check the tcp connection in resource ...
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1answer
192 views

Linksys SRW248g4p Latency Issues

Pinging between the linksys the ping times are averaging 40ms. I have evening tried pinging between two Linksys switches that are connected to each other directly using the GB ports. There have no ...
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3answers
140 views

How to determine the fastest location for a server?

I'm in Australia and I'm looking at US hosting options because the prices here are embarrassingly extortionate. Are there any good, free online tools I can use to find out which location in the US has ...
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3answers
1k views

How much does a IPtables router slow down a connection?

I would like to know if introducing a new gateway in my network will slow things down. The question may sound unclear but here is an illustration: Before Installing gateway server Main Router ...
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4answers
7k views

Accurate way to check latency between Server?

First of all, I hope my post are is posted in the right section . Below are something i got confused hope you one can help. My business partner 's IP server are in: Sanjose, CA , and I am looking for ...
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1answer
575 views

What’s the best switch with bandwidth limiter for my Internet Cafe?

I'm looking for the best switch and router for my internet cafe, that have bandwith limiter and have low latency... Thanks
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7answers
10k views

Latency in TCP/IP-over-Ethernet networks

What resources (books, Web pages etc) would you recommend that: explain the causes of latency in TCP/IP-over-Ethernet networks; mention tools for looking out for things that cause latency (e.g. ...
2
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2answers
388 views

DNS Resolver Speed Techniques

I recently received a reply to my concerns about some DNS servers being slower than others despite all servers being anycast: In practice, most resolvers won't be impacted by the slower paths to ...
2
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1answer
1k views

how can i reduce the lag in my sshd session?

I'm trying to use various ncurses programs through ssh but there's lag up/down in the sshd. I'm wondering if there are any tips like sshd config settings or tcp/ip settings that can help reduce the ...
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3answers
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Akamai vs smaller CDN for small/medium-size ecommerce traffic? (caching, latency, NetStorage)

The small/medium sized online retail company I work for uses Akamai as our CDN for static images, but I'm wondering whether it might be hurting rather than helping and, if it's suboptimal, what we ...
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1answer
79 views

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 ...
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1answer
86 views

Latency of Harddisk-Access WLAN vs USB (Windows)

it would be kind if someone who is an expert on this field state what I have to expect in regards to the latency accessing files for the given scenarios (comparing them): A) Current Windows PC with ...
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2answers
160 views

Is latency the time it takes to get the first byte?

If I request an image from a server, would latency be the time it takes to receive the first byte of the image?
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4answers
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Remote desktop over 500ms latency: What is the best client to use?

We have a very slow RDP session from NYC to India (500ms) and we are looking for a client that will withstand this latency. What do you recommend in this circumstance? Is there a better remote ...
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1answer
872 views

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 ...
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4answers
5k views

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 ...
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1answer
319 views

What is the best way to detect how/where server latency occurs?

I'm managing a small social media site, and its been for the past few days experiencing intermittent server lags. The site will choke loading a page, and moments later, the same page will have no ...
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3answers
736 views

Small TCP Window on WAN between 2 Locations

Site A: Denver datacenter. 60MBPS. Site B: Chicago. 100MBPS. ICMP pings: Packets: Sent = 176, Received = 176, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 74ms, ...
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2answers
635 views

Traceroute provides a route that takes longer than 100 hops

I have a server that I configured using zoneedit. Upon running "traceroute" on it I notice that it takes more than 100 hops. How do I lower the number of hops? Is this really that bad or am I too ...
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3answers
468 views

howto measure network bandwidth/perf

we have a corporate LAN of approx 200 nodes behind a firewall and recently upgraded bandwidth of ISP. Now we want to measure the performance / bandwidth (internet as well file copy perf on local ...
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2answers
498 views

Another benefit of Lighttpd in front of Apache

I have read in a site that another benefit of having Lighttpd in front of Apache is lower number of child processes. Lighttpd will handle keep-alive and client requests while child processes of Apache ...
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3answers
659 views

TCP handshake latency

I have 2 machines on a 100 Gb/s LAN which talk to each other over TCP. When I do a tracert or a ping from the client to the server, even a large ping, I get an answer in less then 1 ms. However, when ...
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5answers
5k views

OpenVPN over TCP, terrible latency but only on Win7 x64

I know TCP encapsulated over TCP is a terrible idea in general, but I can deal with the occasional decreased performance and MTU issues, and the snowball effect TCP within TCP provides where error ...
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2answers
8k views

Internet latency map

I would like to see a latency map, showing the lowest latencies achieved between various destinations around the world. What is for example the lowest latencies achieved between Denmark and India. ...
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2answers
199 views

How remote warfare works when even my satellite TV and remote server has latency? [closed]

This question is after reading this article. My title asks it all. How the connection for this remote warfare works with a absolutely low network latency (which i believe is essential to achieve a ...
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2answers
3k views

Network latency — how long does it take for a packet to travel halfway around the world? [duplicate]

Possible Duplicates: How does geography affect network latency? How much network latency is “typical” for east - west coast USA? If I'm hosting an app in NY, what kind of ...
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8answers
78k views

How much network latency is “typical” for east - west coast USA?

At the moment we're trying to decide whether to move our datacenter from the west coast to the east coast. However, I am seeing some disturbing latency numbers from my west coast location to the east ...