Server Fault Stack Exchange
Server Fault Stack Exchange

Questions tagged [latency]

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

Latency is the time period between a signal being sent and a signal being received. In computer networking this can be the time between a sending of a packet and receiving of a packet.

To illustrate we can use the ping command:

PING google.be (173.194.66.94) 56(84) bytes of data.
64 bytes from google.be (173.194.66.94): icmp_req=1 ttl=47 time=76.6 ms
64 bytes from google.be (173.194.66.94): icmp_req=2 ttl=47 time=74.8 ms
64 bytes from google.be (173.194.66.94): icmp_req=3 ttl=47 time=79.6 ms

The latency here is 76.6 ms.

329 questions
1
vote
6 answers

Why am I getting long TCP connect latency on connect in a LAN (over a cross!)?

I am measuring a time of about 100-150 milliseconds from sending TCP SYN to getting SYN/ACK, between two linux computers connected to the same Cisco switch. Consider: The machines are very powerful, and neither them nor the switch is heavily…
ripper234
  • 5,890
  • 9
  • 41
  • 49
1
vote
0 answers

Ping latency between 2 directly connected PCs

I have a lot of experience with PCIe, some with USB, and little with Ethernet, so the following has got me confused: I'm evaluating the performance of a USB-to-Ethernet controller, vs a PCIE-to-Ethernet controller (nic), in terms of latency. The…
Ori Rosen
  • 11
  • 5
1
vote
1 answer

need for CDN for website in one small country?

I sometimes make websites for businesses that trade only within the UK. If I am only interested in visitors from within the same country where the origin server is based, and the country is relatively small, is there any point at all in using a…
Ollie Williams
  • 123
  • 1
  • 5
1
vote
1 answer

Can't stream media on network

Long story short, at our office network, we can't really certain things. Last.fm downloads an entire song before playing it, and YouTube loads and then all of a sudden the entire video is loaded and it plays. It won't play before hand. iTunes radio…
Daniel Huckstep
  • 539
  • 2
  • 8
  • 19
1
vote
2 answers

What is the minimum gigabit Ethernet latency I can expect?

I have 2 servers sitting in a rack running Ubuntu 16.04 with a 1 meter Ethernet cable between them, both having standard Intel Ethernet adapters. The ping between the two is about 300 us (microseconds). This is a standard latency I've seen in most…
nh2
  • 818
  • 3
  • 11
  • 21
1
vote
0 answers

RDP latency optimisation on worldwide connections

I'm wondering how bigger companys are working around this challenge. Our company gets bigger and therefore we're starting to expand in new countries. Now a new branch office opened straight at the other site of the globe. Of course these Users need…
Shardas
  • 11
  • 1
1
vote
1 answer

Experiencing high latency with server without any server load nor local router latency

I am experiencing a very weird issue and it is hard to synthesize in a simple sentence, so I am sorry if the title of the question is rather shady. So I have a dedicated server running with the following specs: CPU: Intel i5-4590 Quad-Core @…
SmashingQuasar
  • 113
  • 3
1
vote
1 answer

MySql high latency

I try to connect with PHP to a MySql Server and it took in average 2 seconds to establish the connection. We host our Database in Germany (Frankfurt) and the PHP-Application in Singapore. We're hosting on AWS. Our Database Server is a RDS Multi-AZ…
Pawel
  • 113
  • 4
1
vote
2 answers

Is network delay up always the same as network delay down?

If I have a client-server architecture, is the up delay (from the client to the server) always the same as the down delay (from the server to the client)? On a case-by-case basis of latency measurement, of course I would expect there to be minor…
pookie
  • 151
  • 1
  • 7
1
vote
3 answers

Relation between distance and packets travel time

Is there a theoretical estimation for the time needed for a packet to travel from point A to point B? For example 100 ms for every 100km ? I want to estimate the difference of time needed for a device to send a request to a server from different…
user3235881
  • 113
  • 2
1
vote
1 answer

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 10 disk using dd (512 bytes written one …
Pavin Joseph
  • 130
  • 10
1
vote
1 answer

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. The hops go as follows. NY4--tcp--API1--json…
Dmitry
  • 111
  • 2
1
vote
1 answer

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

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 calculators such as this, but most are for TCP so not…
wishihadabettername
  • 111
  • 1
  • 3
1
vote
1 answer

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 10.0.100.10: icmp_seq=157 ttl=62 time=1099 ms 64 bytes from…
Str82DHeaD
  • 582
  • 4
  • 7
1
vote
1 answer

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 beefy VM on VMware 6.0GB RSS forked in 77…
Paiboon Panusbordee
  • 167
  • 1
  • 10
1 2 3
…
21 22