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

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4
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4answers
3k views

finding the best network latency between two countries

I know there are many tools to test for bandwidth and latency, but they all rely on having at least one host from which you can run those tests. I wonder whether there's an online source or some ...
3
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1answer
954 views

tcpdump udp data capture latency

I am using tcpdump to capture UDP packets and analyze network latency between a UDP broadcaster and my server. To calculate latency I compare the source host timestamps reported in UDP application ...
0
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2answers
1k views

What is the internal latency of a Cisco 3560?

Our trading network is very latency sensitive. We use Arista switches for the latency sensitive parts, and we know that the latency there is 600 ns. However, we have a Cisco 3560 in part of the ...
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3answers
223 views

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 ...
6
votes
4answers
3k views

High latency, yet ping shows low latency

We're seeing latencies of ~100-300ms for services accessing a remote resource within the same subnet, yet when we use ping (ping size was of a similar size as of packets sent normally), we see ...
0
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1answer
82 views

use a offside proxy server to optimize site delivery?

Actually we have following setup for our website that gets traffic around the world: All JS, Images, Photos are stored on a CDN: Cloud Files ("Akamai light" powered). The WebApp server who send the ...
2
votes
1answer
722 views

Distributed File System Replication (DFSR) between Server 2008 & Server 2008 R2 over Gateway to Gateway VPN causing extreme network latency

The company I work for is in the process of setting up a branch office for one of our clients. We have 1.5 Mbps up/down T1s at each location, a Cisco RV042 router at each location hosting a Gateway ...
0
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2answers
44 views

Ways to estimate which network destination result is shorter/faster network path?

I am writing a program that allows users to supply a list of hostsname or IPs which I will then find out which host connectivity is faster and connect to it. And right as I am typing the question in ...
0
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3answers
106 views

How to log latency from remote sites to web server?

I have a web server that works great for North American users, but users from Asia will have problems every once in a while. I need to collect some data and the first set is to get some trending for ...
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2answers
219 views

Latency, Ping and Other Questions [closed]

In a high traffic application, like an online auction system, few ms could determine 'to win or 'to lose' the 'battle'. I'm from Brazil. Here, I 'ping' local sites - like UOL - and receive replies ...
0
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1answer
71 views

Fastest secure machine-machine network configuration [closed]

We currently host a large number of our application servers in a 3rd party data centre. Connectivity is then provided to our users across Europe through the vendor’s network. These machines run ...
1
vote
1answer
383 views

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 ...
1
vote
1answer
583 views

What is the maximum normal latency for internal gateway switch?

I've been observing the ping latency to my server's internal gateway switch from my server machine. I noticed the ping spikes to as high as 500ms at times. Is this a possible indication that the ...
4
votes
2answers
151 views

OS parameters tuning for latency improvement

We are trying to improve the average latency of Java proxy application. The Java application receives a message from a client and proxies it to a necessary server. The protocol is binary, ...
3
votes
1answer
820 views

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 ...
1
vote
3answers
2k 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
votes
1answer
112 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 ...
1
vote
1answer
280 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) ...
3
votes
3answers
221 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 ...
2
votes
2answers
158 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
votes
2answers
94 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 ...
0
votes
2answers
1k 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 ...
2
votes
2answers
769 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 ...
1
vote
1answer
100 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. ...
3
votes
1answer
210 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 ...
2
votes
6answers
4k 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 ...
38
votes
7answers
10k 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 ...
1
vote
3answers
942 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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vote
2answers
1k 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 ...
4
votes
2answers
196 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 ...
1
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3answers
2k 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 ...
-1
votes
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
votes
1answer
252 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
57 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?
2
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5answers
175 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
votes
1answer
250 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 ...
3
votes
2answers
8k 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 ...
4
votes
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 ...
0
votes
1answer
185 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 ...
2
votes
3answers
135 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 ...
1
vote
3answers
840 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 ...
0
votes
4answers
2k 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 ...
0
votes
1answer
505 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
4
votes
7answers
5k 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
votes
2answers
292 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
votes
1answer
862 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 ...
4
votes
3answers
3k views

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 ...
1
vote
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 ...
0
votes
1answer
80 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 ...
1
vote
2answers
158 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?