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

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6
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1answer
2k views

Limit incoming and outgoing bandwidth and latency in linux

I realise many similar questions have already been asked, but so far I've yet to find a solution to my problem. I have a virtual linux server (running Debian Squeeze) that I use for testing of ...
0
votes
1answer
41 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 ...
5
votes
2answers
93 views

Trans-atlantic VOIP

We're a Canadian business on the east coast and will soon be opening up a new call centre in Australia. This new call centre will be handling our graveyard shift and will be overlapping with the ...
4
votes
1answer
676 views

Hyper-V guests: intermittent latency

I am seeing latency on a Hyper-V host and its guests lately. When I run ping -f from a Linux prompt, I see the dots "pulsate" like a heartbeat indicating 2 successive latency spikes within 1 second ...
1
vote
0answers
57 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 ...
23
votes
13answers
43k views

Why is the response on localhost so slow?

I am working on a tiny little PHP project for a friend of mine, and I have a WAMP environment setup for local development. I remember the days when the response from my local Apache 2.2 was immediate. ...
0
votes
2answers
36 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
vote
1answer
95 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
66 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
votes
1answer
5k views

what is acceptable datastore latency on VMware ESXi host?

Looking at our performance figures on our existing VMware ESXi 4.1 host at the Datastore/Real-time performance data Write Latency Avg 14 ms Max 41 ms Read Latency Avg 4.5 ms Max 12 ms People ...
2
votes
2answers
182 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 ...
0
votes
2answers
99 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 ...
3
votes
1answer
818 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 ...
0
votes
2answers
247 views

How can I determine the fastest memory based on latency and bandwidth?

I've got some older hardware that needs a memory upgrade, and I was trying to determine what RAM would be the fastest on the platform. My platform takes DDR2 667MHz which is (slightly) more ...
4
votes
2answers
270 views

Why do tracert latencies not add up to ping latency?

One might expect the sum of the tracert latencies to equal 267ms:
2
votes
4answers
279 views

Network Latency over WAN

Let me take a minute to explain the background of the challenge I am facing. My company has offices in US and Asia. The users work on large CAD files. The office in US has NAS (Network Attached ...
0
votes
0answers
12 views

Email duplicated from Barracuda Cloud layer?

Incoming email to our domain first goes to the Barracuda Cloud Protection Layer before being passed to our local Barracuda 300 antispam appliance. It then goes to our email server (CommuniGate). ...
2
votes
2answers
107 views

exchange accounts on outlook 2010 freeze randomly due to high latency

One of our clients is running a windows SBS server 2011, with users in both a TS environment and local lan computer access. This is a small environment with approximately 35 users. The symptoms we ...
1
vote
1answer
217 views

Amazon EC2 and Amazon RDS in Same Network

We have deployed our application in EC2 instance and our database is in RDS which is db.m2.2xlarge. I see some minor slowness in our application when compare to our QA environment where has both ...
10
votes
4answers
4k views

Why do mobile networks have high latencies? How can they be reduced?

I'm increasingly seeing mobile networking technologies being used to get internet access in areas where it is otherwise not available. While mobile networking is usually not yet viable as the primary ...
0
votes
1answer
120 views

Unicorn rails server with Apache

I'm looking for the best setup to use in conjunction with Unicorn. Are there clear advantages or disadvantages to using Unicorn rails server with Apache? Should I consider using NGINX? I'm concerned ...
3
votes
3answers
248 views

Network Latency and Timing as shown by Chrome

I'm trying to understand why a static image being served by IIS is taking ~ 182 ms to load. Using chrome I captured the following timing information. When I request the same image by opening ...
-1
votes
1answer
42 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 ...
0
votes
0answers
66 views

My redis' fork time is slow and impact query performance a little. What should I do to check?

I used redis with RDB option only. It used 2GB of memory. When it forked, it used about 10 seconds to completely save the file. When I check up with redis.io site, I found this latency stat: - Linux ...
1
vote
1answer
47 views

Microwave Link Latency

An internet provider installed us a microwave link: The issue is that: The ping from our side to the gateway is about 1-2 ms, which is great, but it remains like this for only 12 hours, then it ...
0
votes
2answers
87 views

How to investigate initial server response latency (2.9s) of wordpress/nginx site?

I infer it takes roughly 3 seconds to build HTML and send it back. Is there something obvious that I am missing? Hardware: 2 CPU, 4 GB RAM, 100 gb HDD Stack: Fresh CentOS, Nginx, Wordpress DD perf ...
0
votes
2answers
38 views

How do I choose servers to minimize latency to a critical third-party service?

I would like to spin up a cloud server that has the minimum possible ping to a third-party service. Do you just get on AWS and keep making servers in new Availability Zones until the ping is good ...
0
votes
2answers
468 views

ESXi - What could be the cause of high write latency on a local datastore?

I have a ESXi 5.5 server and I'm experiencing high write latency on a local datastore. This datastore is on a virtual disk provided by a RAID card (two SATA disks on RAID 1). When I copy large ...
0
votes
0answers
43 views

Jitter Calculation

I have recently come across the term Jitter in the RFC3550 [page 40]. I have a question regarding this, that what if I add all the Jitter(J) values that I get after receiving each packet and in the ...
3
votes
2answers
2k views

sssd and ldap authentication cache

On our box running OpenSUSE 12.2 we have installed OpenLDAP and sssd daemon. We are using these two services for user authentication. Recently we created a script which creates new web-users for our ...
1
vote
1answer
97 views

Simulating latency to a URL using ipfw

How can I simulate latency to a single URL? I tried following to simulate latency to a single URL by adding a ipfw rule. sudo ipfw add pipe 1 ip from myurl.com to any #(response of running above ...
0
votes
2answers
83 views

Amazon Ec2 with LAMP and RDS: how to easely replicate in different regions

I'm a newbie about Amazon cloud and I need an help in order to reduce the geographically latency of a website. I have an Amazon Ec2 with LAMP and RDS in EU Irland. I wish to have the same ...
0
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0answers
176 views

CentOS Latency High Troubleshooting

I have two CentOS servers connected via a 10 Gb fiber optic cable with a network emulator connected between them. All three units sit on a desk in the lab. There is also a regular 1 Gbit Ethernet ...
0
votes
1answer
143 views

Why my 2nd ip from traceroute is not answering the ping anymore? [closed]

My Internet is really laggy today, I did a tracerout and I realize that I'm having no answer from an ip at the beginning of the traceroute. see: Tracing route to 12.129.202.154 over a maximum of 30 ...
0
votes
0answers
91 views

Unexplained Packets being dropped

I have two servers one sending large amounts of data to the other, we are noticing that one server is sending data to the other but the receiving server is missing some of the data or packets. I am ...
1
vote
0answers
28 views

Latency on intermediate network

For the past week I have noticed that most of the times pages running on my server are very slow. Sometimes they load quickly, but only about 15% of the time. Using an online traceroute tool I have ...
2
votes
2answers
529 views

Disk latency within a virtual machine

I've been looking at some performance issues on a clustered virtual machine in our organisation. Actually this problem seems to affect most of the virtual machines I have looked at. Both host and VM ...
1
vote
0answers
269 views

High latency on domain with CDN

High latency on domain with CDN I have problems with latency on my server, these are the tests I made with blitz.io Latency album http://imgur.com/a/bCmwo I would uploaded images here but it ...
2
votes
1answer
168 views

Hosted Network Latency

Background I have a new hosted, dedicated database server behind a dedicated firewall (Cisco ASA 5505 Sec+). The plan is to have a virtual (aka "cloud") web server or two on the other side of the ...
3
votes
2answers
126 views

Appropriate network monitoring tool(s) for logging hiccups

I have a customer who has problems with our software crashing from time to time. Unfortunately, if you unplug the network cable in the middle of a transaction our software will crash every time and ...
-2
votes
1answer
67 views

Is it bad for latency to have ping running 24/7? [closed]

I want to display my avg latency time for whatever connection I currently have to the internet in a widget. Would having ping run continuously make my connection suffer?
0
votes
0answers
85 views

General network slowness, cause appears to be SBS 2008 generating DCOM errors

I've got a weird issue with a small business network; mostly XP clients, with some 7, and an SBS 2008 server. It runs on a 24 port Dell switch. Ping times from workstation to workstation, as well as ...
0
votes
0answers
45 views

2 cisco 1941's, high latency during low network load

We have a point to point connection between 2 cisco 1941, the weird thing is that during low bandwith usage we experience high latency (peaks of 200+ ms, when 8-20 is normal) we currently use a ...
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
0answers
242 views

how to disable MSI on tg3 driver?

got some new HP DL380p G8 for Centos. What's the correct options to disable MSI for the onboard Broadcom NICs? I tried disable_msi in modprobe.conf.local and it doesn't work. Thanks Will
1
vote
1answer
186 views

Latency, Nginx & PHP-FPM

I have a high load dynamic PHP web service which I have recently moved from Apache2 to Nginx and PHP-FPM. I am finding that the average request latency has increased from 0.5s to 1s since the move. ...
0
votes
1answer
154 views

35 times increased latency between data send rate of 1 millisecond vs 100 microseconds. WHY?

Experiment hping -S --data 100 -c 100 10.56.1.2 -i u100 round-trip min/avg/max = 0.5/14.0/15.8 ms hping -S --data 100 -c 100 10.56.1.2 -i u1000 round-trip min/avg/max = 0.3/0.4/4.8 ms Observation: ...
0
votes
0answers
74 views

how to determine whether network switching equipment latency is OK for VDI delivery?

Is there a good (proper) way to test whether network switching in place is good enough for VDI delivery? I read a Cisco UCS whitepaper that stated that they observed 3.2 ms latency across their test ...
0
votes
0answers
167 views

FTP Transfers Slow Between 2 Servers

Between 2 dedicated servers, hosted in 2 different DCs (different companies), the FTP upload speeds are always much slower than the max connection speed. Specs: Windows 2008 on both. Quad core/8 GB ...
7
votes
1answer
2k views

High latency/drops between Cisco switches in two locations. How to troubleshoot?

I'm receiving user complaints about poor network application performance between two parts of a large warehouse facility. The software is a curses-based terminal application running on a Linux server. ...