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Old 04-24-2014, 02:23 PM
Status: "I am in preparation mode!" (set 4 days ago)
 
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I recently applied for a position that required me to test the voice quality of my phone. I failed the test due to the packet loss being too high. They want it to be zero. I called my carrier and he did a test and said everything should be fine. Now I am having issues with my computer. Can someone explain to me what packet loss is in plain terms and if my telephone could be the problem.
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Old 04-24-2014, 03:33 PM
 
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When you send information to the server or receive it from the server, you're doing so in small little packets. If one gets lost on the way to the server, the server will go "hey computer, I didn't catch that last bit, please resend" and the computer obliges. This creates latency (lag) spikes and degrades quality on things like VOIP because packets may be lost and not re-sent (if you're on the phone and packets were being resent, it would be a jumbly mess, so typically they're just dropped).

Packet loss can happen because of your router, your ISP, quality of cabling between the two, etc.

Go to pingtest.net and test several servers, if your packet loss is zero with that test, you can be sure that your connection is ok.
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Old 04-24-2014, 04:52 PM
 
Location: Tyler, TX
15,194 posts, read 17,683,182 times
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Quote:
Originally Posted by adyn View Post
When you send information to the server or receive it from the server, you're doing so in small little packets. If one gets lost on the way to the server, the server will go "hey computer, I didn't catch that last bit, please resend" and the computer obliges.
The text in green is incorrect. SIP is a UDP protocol, so it doesn't keep track of which packets were received. It just blasts packets at the destination.

There are some transactions in SIP (e.g. INVITE) that get an ACK, but for the most part, packets are just sent down the wire in the hopes that they'll make it.

Quote:
Originally Posted by adyn View Post
This creates latency (lag) spikes and degrades quality on things like VOIP because packets may be lost and not re-sent (if you're on the phone and packets were being resent, it would be a jumbly mess, so typically they're just dropped).
Audio packets are never re-sent, for the reasons you specified. There's no point in retransmitting a lost packet that should have been played to the user two seconds before the packet he just heard.

OP - adyn did a good job of explaining what packet loss is, but we really don't have enough info to help you troubleshoot the problem.

As for your potential employer wanting "packet loss to be zero," that's a pretty serious requirement. Honestly, it sounds more like an excuse to not hire you than a legitimate prerequisite to employment. No network operator can guarantee that 100% of the data transmitted is going to make it to the destination. They can't - that data is traversing multiple networks, most of which they have no control over.

What hardware and/or software were you using to place (or receive) the call in question? And do you know what they're using on their side?
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Old 04-24-2014, 05:28 PM
 
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good info, thanks
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Old 04-25-2014, 08:23 AM
Status: "I am in preparation mode!" (set 4 days ago)
 
5,514 posts, read 5,494,602 times
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Quote:
Originally Posted by swagger View Post
The text in green is incorrect. SIP is a UDP protocol, so it doesn't keep track of which packets were received. It just blasts packets at the destination.

There are some transactions in SIP (e.g. INVITE) that get an ACK, but for the most part, packets are just sent down the wire in the hopes that they'll make it.


Audio packets are never re-sent, for the reasons you specified. There's no point in retransmitting a lost packet that should have been played to the user two seconds before the packet he just heard.

OP - adyn did a good job of explaining what packet loss is, but we really don't have enough info to help you troubleshoot the problem.

As for your potential employer wanting "packet loss to be zero," that's a pretty serious requirement. Honestly, it sounds more like an excuse to not hire you than a legitimate prerequisite to employment. No network operator can guarantee that 100% of the data transmitted is going to make it to the destination. They can't - that data is traversing multiple networks, most of which they have no control over.

What hardware and/or software were you using to place (or receive) the call in question? And do you know what they're using on their side?
My carrier is TWC. The modem I have is ARRIS. It is functioning as modem because I did not activate the wireless internet feature. I think 0% is a bit ridiculous too. I do not know what they are using. Should I go to ping test to check.
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Old 04-26-2014, 02:06 PM
 
Location: Southern California
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Quote:
Originally Posted by goodlife36 View Post
My carrier is TWC. The modem I have is ARRIS. It is functioning as modem because I did not activate the wireless internet feature. I think 0% is a bit ridiculous too. I do not know what they are using. Should I go to ping test to check.
Do you have a cable modem with a landline and the landline is a digital line from twc? Are you trying to use a VoIP app on your PC? The packet loss can be caused by application on your PC.
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Old 04-26-2014, 03:43 PM
Status: "I am in preparation mode!" (set 4 days ago)
 
5,514 posts, read 5,494,602 times
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Quote:
Originally Posted by thelopez2 View Post
Do you have a cable modem with a landline and the landline is a digital line from twc? Are you trying to use a VoIP app on your PC? The packet loss can be caused by application on your PC.
I plugged the telephone cord into the modem. The employer tested my computer and phone connection. Computer passed but the packet loss failed. What application are you referring to?
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Old 04-26-2014, 05:11 PM
 
Location: Southern California
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My point is you can have programs on your computer resulting in packet loss. There are too many variables, are there other people using the Internet connection. Are you downloading streaming, or have other apps running. Maybe too many other people are downloading things. Are you using a proxy or some type of anonymizer?
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Old 04-27-2014, 07:14 PM
 
Location: Port Charlotte
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Cable systems can drop data. We went to FIOS because of the data loss. Most cable systems are still 1980's cabling, susceptible to deterioration, etc.
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Old 04-28-2014, 02:05 PM
 
Location: Southern California
4,350 posts, read 4,929,984 times
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Are you trying to be a telemarketer that will call me during dinner?
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