Severe Latency (almost 500ms) during 1 File Upload
ThndrSki
Newbie

My VOIP connection internally started severely degrading the other day at my house during a time when I was uploading a file and I only had 2 devices connected to the router. My laptop which was uploading, and my Grandstream VOIP phone. I have never experienced anything like this before, as I've uploaded to my company server many times. I called FIOS tech support and the tech was useless, instantly tried to sell me the fastest Quantum package they had, and then once I explained my issue, just wanted off the call and sent a new router.

Has anyone else seen this? You mean to tell me if I start uploading 1 file, I should expect my latency to jump to almost 500ms?! During this time, this completely impacts any VOIP call I am making.

No Activity: Last Result: Download Speed: 25705 kbps (3213.1 KB/sec transfer rate) Upload Speed: 4571 kbps (571.4 KB/sec transfer rate) Latency: 92 ms Jitter: 1 ms Packet Loss: 0% 6/11/2014 1:13:58 PM

During Upload: Download Speed: 10098 kbps (1262.3 KB/sec transfer rate) Upload Speed: 1237 kbps (154.6 KB/sec transfer rate) Latency: 461 ms Jitter: 5 ms Packet Loss: 0% 6/11/2014 12:59:55 PM

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Re: Severe Latency (almost 500ms) during 1 File Upload
gs0b
Community Leader
Community Leader

You have to remember that IP was never designed for time sensitive data transfer such as voice, audio and video.  There is nothing in the protocol itself to control latency.  Latency can be controlled by routers that are protocol aware and can enforce Quality of Service (QoS), but even then they are limited in what they can do.

The big problem with the co-existence of general purpose data and time sensitive media data on the same network is packet size.  Only one packet at a time is every transferred across a link.  If a file transfer uses full size (1518 bytes) or jumbo packets (9000 bytes), VoIP packets will have to wait a while until they get their turn at the link.  Media devices deal with this by increasing buffer sizes which means greater latency.

If your company's server recently changed settings to allow jumbo packets, that could explain the change in behavior.

Some VoIP products can be installed as a gateway between the home network and the Internet while providing some QoS.  If your equipment supports this you should try it.  Even then, large packets are a problem as they can't (easily) be broken up.

Good Luck.

Re: Severe Latency (almost 500ms) during 1 File Upload
smith6612
Community Leader
Community Leader

@gs0b wrote:

You have to remember that IP was never designed for time sensitive data transfer such as voice, audio and video.  There is nothing in the protocol itself to control latency.  Latency can be controlled by routers that are protocol aware and can enforce Quality of Service (QoS), but even then they are limited in what they can do.

The big problem with the co-existence of general purpose data and time sensitive media data on the same network is packet size.  Only one packet at a time is every transferred across a link.  If a file transfer uses full size (1518 bytes) or jumbo packets (9000 bytes), VoIP packets will have to wait a while until they get their turn at the link.  Media devices deal with this by increasing buffer sizes which means greater latency.

If your company's server recently changed settings to allow jumbo packets, that could explain the change in behavior.

Some VoIP products can be installed as a gateway between the home network and the Internet while providing some QoS.  If your equipment supports this you should try it.  Even then, large packets are a problem as they can't (easily) be broken up.

Good Luck.


As a rule of thumb, it's not a good idea to be sending Jumbo packets (>1500 bytes) over the Internet unless you have a really solid route or you run your own backbone with a guaranteed delivery rate. The chance for packets getting damaged from congestion or intermittent lapses in connectivity increases with the size. Plus packet fragmentation is not cool.

But this is a case of connection saturation and is perfectly normal per gs0b. You will need to set up QoS in your router to control the upstream traffic a bit more, or you will need to have the application performing the upload rate limit itself to a slow enough rate to prevent VoIP from being affected. Or, you could just buy a bigger pipe like Verizon was pushing and hope that the pipe itself is larger than the end to end connection can handle, effectively throwing bandwidth at the problem.

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Re: Severe Latency (almost 500ms) during 1 File Upload
ThndrSki
Newbie

I agree - thank you for the advice.  Do you know if a good QOS guide for the MI424WR Rev I router is available?

It doesn't seem very intuitive at it has all interfaces and it doesn't make sense which is superceeded by the other?

I would love to put in my VOIP QOS rules!

image

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Re: Severe Latency (almost 500ms) during 1 File Upload
Hubrisnxs
Legend

I'll add my own personal experience with a similiar issue that took me quite a while to figure out (partially because it wasn't my machine that was affected, but another person in the network).

Whenever I did a large download or stream, it zapped almost everyone else on the network.  We had more than suifficient bandwidth.   a symptom we saw was MASSIVE LATENCY going on, which kind of points me to your issue.

Believe it or not, my machine was on a nasty wireless channel that had tons of interference, and that interference in some fashion amplified the latency.   

Once we cleard up the connection to my machine, the other machines regained useful internet connectivity.

I'll say it this way, if your machines are wireless and you're having this trouble, then don't discount the possibility of simple wifi interference.  

hardwire the machine for a test if possible,  or simply begin changing wifi channels.

Verizon's in home agent tool does a fine job of wifi channel changing so download that at www.verizon.com/connect

OR if you're relatively handy in a router interface (gui) then you can follow these instructions.

log into the router

select wireless settings at the top

select basic security on the left

find the option for wifi channels (i am pretty sure it's opt 3)

Start with channels 1, 6 and 11.    after each change immediately test it, and move to the next channel if unsuccesful. 

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Re: Severe Latency (almost 500ms) during 1 File Upload
ThndrSki
Newbie

Thank you for the suggestion, although the machine uploading is hard wired and I didnt have any wireless devices running during the time.  

Even powered off my tablet to make sure it wasn't a NIC/wireless NIC going bad.  I'm sure it has to do with large packet latency somehow and want to figure out how to correctly enter my QOS rules to make sure it won't happen in the future.

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Re: Severe Latency (almost 500ms) during 1 File Upload
Hubrisnxs
Legend
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