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

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30 views

Is it normal to have unstable ping on local AP

I am about 1 or 2 level better than newbie in networking so i hope i didn't say anything wrong, except for my english. I have AP, TP-LINK TD-W8951ND that connected with ADSL. MY PC1 connected by ...
3
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0answers
65 views

Latency (wait ttfb) on EC2

My application is crawling a website. I use this crawler : https://github.com/rfussien/leboncoin-crawler On my dev environment, the latency is acceptable (3-4 sec) but on my prod server (ec2 ...
0
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0answers
16 views

High latency from clients accessing SQL Anywhere backed application

Apparent high latency from clients accessing SQL Anywhere backed application The setup: Server: Running Windows Server 2012 R2 Standard /w Hyper-V role VMs on this server: -2 DCs -1 terminal server ...
0
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0answers
33 views

What is an efficient means to serve a dynamic website globally, in terms of latency? [duplicate]

We're using Amazon's AWS infrastructure. At one time, we did have a load-balanced setup across geographic regions, and our database cluster was divided between those regions. To reduce costs for the ...
0
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0answers
13 views

high ping6 latancy for cisco C3750

I have one cisco router with IOS software ( IOS Software, C3750 Software (C3750-IPSERVICESK9-M), Version 12.2(55)SE1). Recently, there is big ping latency, when I ping from one HP Gen6 SERVER which ...
0
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1answer
44 views

Long latency on Windows/IIS virtual hosts

We have a development server on which we have about 10 identical virtual sites. Whenever we pull up one of the sites, it is very slow (up to 30 seconds for the login page to show up). Once logged in, ...
0
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0answers
25 views

Network issues or tcp stack load

I am running a NoSQL (aerospike) cluster on a set of identical hosts (ec2). Once in a while one of them would start timing out on queries and connections, and pings to it would go from < 1ms to ...
6
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3answers
818 views

Do changes in SPF records take time to propagate?

I'm setting up SPF records for my domain, and am not getting the results that I expect. It's quite possible I'm making some sort of mistake, but first I'd like to ask: does it take time for the ...
0
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0answers
163 views

Sometimes unable to tune Linux TCP stack for improved high-latency performance

I have been unsuccessfully trying to apply the TCP Tuning techniques discussed at http://fasterdata.es.net/host-tuning/ As you'll see when you read through the entire question, sometimes the es.net ...
0
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1answer
37 views

monitor and log speed of a program working with network files

We are using a CAD program on multiple computers in a network. All files and projects are stored on a network storage. The users moan about long waiting times while opening from and saving to the ...
0
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0answers
44 views

Azure Web App Latency

I have a simple Azure Web App setup using a single Standard Small Instance type in Central US region. The site itself is running a node.js website. I noticed google crawl was reporting average ...
0
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0answers
66 views

ping timeouts with light http traffic on T1 connection

I have a T1 over copper connection and started to notice that if I run ping while loading an http page (http://google.com) I get intermittent timeouts in ping. Is this normal? I expected some ...
2
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1answer
83 views

Windows 2012 Shared Drives Odd Latency Issue

I have a Dell T110 II running ESXi 5.5 with a Windows 2012 R2 instance running with the following roles: ADDS DHCP DNS File/Storage Svcs WSUS I have two shared folders -- Scans and Data -- which ...
0
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0answers
65 views

Ping RTTs vs UDP Ping Pong RTTs

Network Topology (wired): ServerA - 1Gb - Switch - 10Gb - Firewall - 10Gb - ServerB Pinging ServerB from ServerA shows round trip times (RTTs) of ~1.2 milliseconds. UDP packet 'ping pong' between ...
2
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0answers
98 views

SSH Client sporadically hangs for few seconds

On Ubuntu 14.04 LTS when I use SSH client, it hangs sporadically for few seconds every minute or so. no input is lost is just delayed. SSH -V OpenSSH_6.6.1p1 Ubuntu-2ubuntu2, OpenSSL 1.0.1f 6 Jan ...
0
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1answer
310 views

Ubuntu Trusty: virt-manager performance over WAN… 40+ secs freezes

I'm using the virt-manager GUI 0.9.5-1ubuntu3 on my laptop running Ubuntu 14.04 against a server located some distance away (same OS) and getting rather unpleasant performance. Laptop-server pings ...
-1
votes
1answer
101 views

Why the latency increases on highload? [closed]

We have a system built on AWS. We use Beanstalk, we have autoscaling, our database (mysql) is hosted on RDS. We use apache and php. We wanted to test our system on highload. So, we chose large ...
0
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0answers
72 views

Increasingly high connect times for static files with Apache

My client is running a PHP application using Apache 2.4.7 and php-fpm. Apache is configured to use mpm_prefork. I am working on optimising load times. I use FireFox dev tools for profiling, and I ...
-1
votes
1answer
69 views

How to reduce latency? [closed]

I am looking to build something where you can have a workstation/server in one location, and access it remotely using a video stream of the screen to do as you wish. My reason for wanting low latency ...
0
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0answers
260 views

Getting chunks of high ms when pinging local / external IP addresses?

I am having difficulty identifying what a specific problem with one of your vlaned networks. They have a voip phone which regularly cuts out during long phone calls. I have done several ping tests ...
3
votes
1answer
741 views

How do I test my internet connection speed via a Microsoft Windows Terminal?

I currently have two production servers. One running Windows Server 2003 and the other Windows Server 2008. When I open the Reliability and Performance Monitor I see a Network section that only goes ...
0
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0answers
144 views

Optimizing Pfsense IPSec VPN for a high latency environment

I have two PFsense routers connecting two networks with high latency between them. What can I adjust to improve file transfers between these two networks?
0
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2answers
355 views

extreme ping latency in WDS network

I have setup a wireless network at work office with the following config: 192.168.1.1: TP-Link 941 Router, Root AP, connected to internet 192.168.1.2: TP-Link 901 AP, WDS Repeater, connected to ...
3
votes
1answer
218 views

Brocade DCX 8510 inter DC latency - understanding OIDs to find L1 issues

Trying to determine if there is some intermittent inter DC latency on the FC links, but only have access to the OID counters for the DCX 8510. Since it is a L1 link over DWDM there are no stats from ...
2
votes
1answer
756 views

ELB - High latency when enabling cross-zone balancing

I'm working on improve our infrastructure reliability in AWS and one of my tasks is enabling cross-zone balancing on our ELBs. Our ELBs receives around 20K request by second on rush hours as well as ...
1
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2answers
396 views

Performance Tuning Linux [closed]

Performance Tuning/ Monitoring/Latency keeping in mind I see following 4 items & in each item they are lot of tools. CPU Memory IO Network What I see following tools we do use. vmstat mpstat ...
1
vote
1answer
768 views

Why the time taken to fetch results of a query for 10,000 times from a RDS is so uneven? (experiment)

tl;dr : Why the time taken to fetch results of a SELECT statement for 10,000 times from a RDS when requested from an EC2 is so uneven? Updated the question with results of small and medium RDS ...
11
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3answers
17k views

Intermittently high ping times to router via Wi-Fi

On my local network there are (among others) 5 machines (running Debian Jessie or Arch) wirelessly connected to a Netgear WNDR4000 router. Below is a graph of the ping times to the router from each of ...
3
votes
2answers
1k views

Need ultra-low latency, how to minimize?

I have several Windows Server 2008 R2 machines that act as clients and are connected to another server in the same datacenter. I don't have access to teh server. I need to minimize latency between ...
0
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0answers
157 views

Windows Azure VHD Upload Inconsistencies

I'm a little over 2 days deep into a 5 day .vhd upload using the Add-AzureVHD in Windows Azure Powershell and I'm perplexed to the speed (or lack thereof) of this operation. The .vhd is a 300GB file ...
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votes
3answers
1k views

What network performance is required for thin clients?

I am building a network with approx. 1000 thin clients. I intend to run them over VNC. What type of LAN bandwidth and latency are required? What type of hardware will provide that? If, instead of ...
0
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1answer
213 views

how to choose right SFP 1000BASE-T transceiver? [closed]

I want to connect SFN7122F network card to 1000BASE-T (1 GB cooper Ethernet). I've found a lot of transceiver and I don't understand how should I choose one: ...
1
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2answers
264 views

SMB Latency Issue with Multiple Users

We have a program that works by being shared over the network as a normal Windows Mapped Drive. You run the program from the mapped drive and it stores its files in flat file databases in that mapped ...
0
votes
1answer
350 views

OpenVPN + Scrambled patch on Amazon EC2

Yesterday I deployed a regular OpenVPN installation on Debian Squeeze / Amazon EC2. The VPN server is in Singapore and I connect to it from China Mainland. Later on, after some tests I had to start ...
3
votes
1answer
2k views

difference between taskset and cpuset

I'm trying to reduce the latency of my linux network application. I've learned that there are two tools for "binding" a program to particular CPU core: taskset and cpuset. Which one should I prefer? ...
4
votes
2answers
6k views

Low latency TCP settings on Ubuntu

There is a server for measurements running on Ubuntu in my lab . And there is C program, which receives data through TCP connection and should as soon as possible send a reply. Network latency when ...
-4
votes
1answer
109 views

multiple domains, one static IP address and latency [closed]

how is latency affected when multiple domains are using one single static IP address ? The scenario is in shared web-hosting By latency meaning the DNS lookup the client has to do. As far as I ...
0
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0answers
192 views

MySQL replication across availability zones in AWS resulting in lag

I have 3 EC2 instances, each running MySQL. 2 are slaves replicating from the master. The master is located in the availability zone eu-west-1b. One of the slaves is in the same zone, and the other ...
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votes
1answer
47 views

Users unable to connect due to an unknown plausible reason [closed]

========================= Warning: Long thread; includes a lot of information to give you some basic understanding of my issues. If you rather not read it, then here are my questions: 1) Does Linux ...
0
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1answer
673 views

Lotus Notes Error - “Specified Network name no longer available”

I work for a bank who is using Lotus Notes email and during the transition from Windows XP to Windows 7 the Lotus Notes client was upgraded from Client 8.0.2 to 8.5.3. Given that these were the only ...
0
votes
0answers
80 views

Why is my server so slow to accept connections?

I've noticed that my server seems to be very slow to accept connections - i.e. when analyzing the load time using the Chrome event map, it shows that some tasks can spend multiple seconds waiting for ...
0
votes
1answer
973 views

How do I troubleshoot latency issues with elastic load balancer (ELB) in Amazon AWS?

We have a web app and API hosted at Amazon AWS, with three environments - development (dev), testing/staging (uat), and live. Each environment has a load balancer, two EC2 instances and an RDS ...
1
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0answers
2k views

upstream timed out (110: Connection timed out) while connecting to upstream

I have my backend in France and one of my frontend servers is in Japan. This issue doesn't happen with any other of my frontends, only this Japan server, which already has about 2s latency from most ...
0
votes
2answers
740 views

SMB2 over 1GB PTP Link - 10ms latency

Maybe I'm expecting way more from SMB2 than what's realistic. Here is the scenario. Windows 7 Client (Local) A) Win2008R2 Server (LAN -- 1GB, <1ms) B) Win2008R2 Server (WAN -- 1GB, 10ms) ...
1
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1answer
1k views

UDP bandwidth calculation based on packet size, request rate and latency [closed]

I need to estimate the bandwidth for a measurement application to be written that uses UDP. I have a good sense of the numbers but am not sure how to put them together. I checked a few throughput ...
1
vote
1answer
216 views

Network ping replies: latency alternates low and high

I'm experiencing some troubles with one machine in my network. When I ping it the ping replies rotates like this : 64 bytes from 10.0.100.10: icmp_seq=156 ttl=62 time=100 ms 64 bytes from ...
3
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2answers
3k views

Is there anything I can do to decrease waiting time for my static http requests (in chrome's network panel)?

I am running amazon aws ec2 micro instance on Ubuntu 14.04 with apache 2.4.9. The reason for having this instance is just to test and to solve some bugs before rolling up the project. Currently there ...
4
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2answers
1k views

Why do tracert latencies not add up to ping latency?

One might expect the sum of the tracert latencies to equal 267ms:
0
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2answers
1k views

Apache has a long lag before responding

I have an Apache server on CentOS that occasionally takes 1-5 seconds to serve a file, including a text file that is 2 characters. I have a JMeter test that gets a few different types of files, and ...
-1
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1answer
72 views

Dedicating a server for latency test

I've created a server to test bandwidth from employees working remote (using speedtest.net mini), but was wondering if anyone knew of a way to setup some software in linux to test latency and possibly ...