I have a VM setup on Azure in "South Brazil" location hosting a WCF service. Although I'm also in Brazil, latency to reach my service in the VM is ~200ms. I have the same service deployed in two other Brazilian hosts and latency to both of them is <60ms.

I've also seen people doing some tests on other Azure datacenters, and latency seems to always be ~50ms as well when near them.

I initially thought that it could be a VM size-related problem, but changing the size to D3 (which is kinda overkill to my service: CPU stays at only ~5%) didn't help at all, latency stayed the same.

Is this normal for South Brazil datacenters, or can it be something else?

Note that as I can't ping an Azure VM, I'm measuring the time in C# to TcpClient.Connect on port 80 with a StopWatch.

Thanks in advance.

closed as too broad by EEAA Dec 13 '15 at 23:41

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  • Did you measure latency to the "other brazilian hosts" (<60ms) using TcpClient.Connect as well? – Jukka Dec 13 '15 at 20:08
  • yes, I've tried both ping and TcpClient.Connect on those others. – andre_ss6 Dec 13 '15 at 20:37
  • Okay, have a look at @EEAA's answer. You could also try azurespeedtest.azurewebsites.net and see what you get – Jukka Dec 13 '15 at 20:44
  • @Jukka Yes, I've seen that website before. Strangely enough, it reports ~200ms for North Central US and >400ms for Brazil South. Sigh. – andre_ss6 Dec 14 '15 at 1:28

There is no guaranteed latency on the public internet. Nor is there a way for any of us to gauge if the latency you're seeing is a result of network congestion or some other issue.

You'll need to take this up with Azure and your ISP.

  • Yes I know. But I only wanted to know if this is consistent with other people hosting VM's on Brazil South's datacenters. If it's not, then I would start trying to troubleshoot the issue. – andre_ss6 Dec 13 '15 at 20:58
  • I've seen from 5ms to 200ms. Not really an exact science. It's all about the route. – Bruno Faria Dec 13 '15 at 23:15
  • I see. Thanks for your answer. Do you have any suggestion of anything I can try, or anywhere I should look for, before contacting Azure support? – andre_ss6 Dec 14 '15 at 1:27
  • Test latency to your server from as many different ISPs as you can get access to. – EEAA Dec 14 '15 at 1:28

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