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

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4
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0answers
60 views

Higher TCP latencies in the latest versions of Linux

In my research group, we recently upgraded the OS on our machines from Red Hat 6.2 to Debian 8.3 and observed that the TCP round trip time through the integrated Intel 1G NICs between our machines had ...
-2
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1answer
25 views

WIndows is not following TcpAckFrequency settings

This is a wierd one. I have set the tcpackfrequency to 2 and windows does not seem to honor it no matter what I do. I would need your help with this. My current template is Internet and congestion ...
2
votes
0answers
15 views

Tradeoffs between cross-cloud and cross-AZ-single-cloud deployments

We have a educational system (federated microservices that are running mostly on AWS EC2, RDS MySQL and a message queue) that is already distributed across regions, primarily for latency hiding, ...
0
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1answer
29 views

Measure latency using ping from a 3rd server

I am new to networking and I wanted this kind of environment. is there any way to measure network latency using ping between two hosts, given the condition you are not logged into either of the hosts? ...
1
vote
1answer
29 views

TCP retransmission delays - lost acks

Maybe somebody will be able to help me out with this. I'm trying to find out if there is anything that can be optimized server-side to reduce delays in case of packet loss. Environment: Windows 2012 ...
0
votes
0answers
8 views

What could be the cause of this latency on IIS7 web cluster MVC?

Specs: Windows Server 2012 R2 IIS 7 .NET 4.0 MVC 3 application 2 servers in a cluster with load balancing enabled Oracle back end We have dozens of MVC3 apps hosted on this server, but only two of ...
0
votes
1answer
44 views

Can high server's CPU usage cause high ping for clients? [closed]

Some users have high ping and they cannot play my multiplayer game due to it. My server application is causing CPU to always rise little by little and when I restart it, it drops. I am working on ...
0
votes
0answers
36 views

How do I reduce private network latency below 0.5ms?

We are migrating from one host to another. Our cluster consists of 10 dedicated linux servers which must communicate on a private network. At the old host we observed latencies below 0.2ms between our ...
1
vote
1answer
45 views

Why does SSHFS I/O latency test much faster than local RAID & NFS?

SSHFS tests for server I/O latency using dd returns very surprising results, so much so that I'm worried this might be some problem either with the test method or configuration. Test 1 on local RAID ...
0
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0answers
56 views

Is it Possible to Configure Receive-Side Scaling on an EC2 Instance Running Windows Server 2012 R2

Currently, I am experiencing some problems on getting a server to run efficiently on an EC2 instance. On my local machine everything runs as expected, but on AWS the servers experience some latency, ...
0
votes
0answers
28 views

How do I investigate latency between my app server and web server?

I have a Rails application running on Thin behind an Nginx instance. When I first start the application, requests are served in a reasonable time but after a few (identical) requests, this suddenly ...
0
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0answers
14 views

Find closest (in round-trip time) hosting to a particular serivce behind CDN

I'm using some service which is located behind CloudFlare CDN, and I need to achieve the lowest latency possible in two tasks: receive lots of messages out of WebSocket WAMP subscription with few ...
1
vote
1answer
19 views

Layout for aws services across regions

Looking for a method to evaluate best layout for services across AWS regions. My setup is compromised from 2 endpoint, a server in NY4 and client in Asia. Between them are 2 api hops and a web server....
0
votes
1answer
30 views

Is connect time all because of latency issue?

Server Question: I have been working on to increase speed of website of https://www.winni.in and I have came across a very strange phenomena. If anyone could, please explain about this. I was ...
2
votes
1answer
49 views

How to debug linux latency issues under network load

I have 12 mixed Ubuntu 12/14 database Cassandra nodes. All nodes are baremetal nodes with SSDs, 1Gb network cards and are all colocated in the same DC (managed colo). Under light operation, the ...
0
votes
0answers
11 views

Latency on Rails App on Heroku

Images linked are screenshots of new relic status on my app. My app takes up to 12 seconds to first byte of render. In my understanding, the graph means rackspace is the reason for the application ...
3
votes
0answers
31 views

Monitor latency by IP on a bridge-enabled host

Is there a tool which captures packets, measure latency in realtime and display it with some IP filtering options for Windows ? My particular setup : Internet -> Router -> Host Master -> Host Slave ...
3
votes
0answers
195 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 T2....
0
votes
0answers
62 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
votes
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
votes
0answers
20 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
votes
1answer
102 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
votes
0answers
32 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 20-...
8
votes
3answers
2k 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
votes
0answers
387 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
votes
1answer
41 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 ...
2
votes
0answers
63 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 ...
2
votes
1answer
117 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 ...
2
votes
1answer
168 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
votes
1answer
458 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
127 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 ...
-1
votes
1answer
82 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
votes
0answers
372 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
1k 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
votes
2answers
488 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 192....
3
votes
1answer
289 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
1k 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
vote
2answers
505 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
954 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 ...
15
votes
4answers
26k 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
votes
0answers
186 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 ...
-4
votes
3answers
2k 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
votes
1answer
253 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: http://h30094.www3.hp.com/product/sku/...
1
vote
2answers
337 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
424 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 ...
4
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? ...
5
votes
2answers
9k 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
131 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
votes
0answers
210 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 ...