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

learn more… | top users | synonyms

-4
votes
3answers
47 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 ...
-1
votes
0answers
24 views

How to determine how much LAN bandwidth is needed? [duplicate]

When designing an office LAN, how do you determine how much LAN bandwidth is needed? I'm not talking about WAN / ISP, only internal LAN bandwidth. Similarly: How much latency is expected for these ...
0
votes
1answer
56 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
vote
1answer
27 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
0answers
40 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 ...
1
vote
1answer
100 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? ...
2
votes
2answers
465 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
38 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
17 views

Syncing client and server time for latency comparison

I'm struggling to sync my server's time (an EC2 instance in Dublin) with my local machine. I'm using sudo ntpdate ntp.ubuntu.com to sync my server's time with Ubuntu's time server. I'm then using the ...
0
votes
0answers
74 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 ...
-2
votes
1answer
33 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
votes
0answers
156 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
35 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
97 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
vote
0answers
968 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
85 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
435 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
96 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 ...
2
votes
2answers
415 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
votes
2answers
348 views

Why do tracert latencies not add up to ping latency?

One might expect the sum of the tracert latencies to equal 267ms:
0
votes
0answers
17 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). ...
0
votes
2answers
204 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 ...
2
votes
2answers
180 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
votes
1answer
50 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
99 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 ...
3
votes
3answers
408 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
vote
1answer
57 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 ...
2
votes
4answers
459 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
2answers
134 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
41 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
0answers
51 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 ...
0
votes
2answers
718 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 ...
1
vote
1answer
132 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
101 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
votes
0answers
243 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 ...
3
votes
1answer
8k 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 ...
0
votes
1answer
246 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
125 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
39 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
1k 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 ...
0
votes
1answer
183 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 ...
1
vote
0answers
330 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
207 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 ...
1
vote
1answer
392 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 ...
3
votes
2answers
165 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
90 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
50 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 ...
1
vote
0answers
274 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
273 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
169 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: ...