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VOIP/Packet Loss/ QOS & Traceroute - Don't Agree

VOIP/Packet Loss/ QOS & Traceroute - Don't Agree

VOIP/Packet Loss/ QOS & Traceroute - Don't Agree

I have had some large packet loss issues which were causing my VOIP audio to drop out. My VSP said it was packet loss (100%) and not them. Always skeptical of Tech's pointing the finger to the other guy, I tested my QOS thru VOIP Speed test and it was only 4% - a disaster. I ran tracerroute and it showed 100% packet loss.

I got my ISP to reset their softswitch and my QOS went up to 99%, this will support VOIP & Audio ok.. HOWEVER, when I run tracroute it STILL shows 100% packet loss..

Anyone know why there is a discrepency??



RE: VOIP/Packet Loss/ QOS & Traceroute - Don't Agree

Traceroute is kind of like ping on steroids. Where are you trying to trace to, and will it respond to ICMP?

The IP you are trying to trace through as a first hop may deny ICMP requests.

What QoS algorythms are you using? Could it be that the they didn't match or the codecs didn't match until the reboot of their softswitch?


RE: VOIP/Packet Loss/ QOS & Traceroute - Don't Agree

Not sure if I understand.. :) The softswitch reboot was at my ISP end from them to me.. The QOS was thru VOIP test.

The traceroute goes from traceroute server to my ISP server.

While there are some delays along the way on the traceroute it seems that my ISP is blocking and is showing the 100% packet loss. My VSP shows the same 100% loss to me.

Interestingly I now show good QOS, 99% on the VOIP speed test which was terrible only 4% before.

Additionall my ISP lowered my DSL download speed to 1.69 from 2.0 MB. which may or may not have had an impact. MY download speed used to flucuate nall over the place, now it is consistent. Upload has always been stable at around 410 mz. Jitter is very low - 0.2.

When my ISP tested me they said my modem (which I have set in bridge mode was unstable with errors, etc. Of course after they reset their softswitch everything is smooth...

Should I get them to put ,my speed back to where it was or does it really not matter in the scheme of things. IS the lower speed more stable, it is constant as opposed to the higher speed which seemed unstable? Any idea why the higher speed would be an issue? I suspect it might be because it fluctuates to get an average speed but this is only a guess.



RE: VOIP/Packet Loss/ QOS & Traceroute - Don't Agree

If you have line conditions that aren't up to snuff, then you will see more loss as the transmission speed goes up. Therefore, it is possible that you have a small fault in your telephone feeder pair and when the ISP lowered the speed from 2 to 1.6 it was enough to negate the line fault.

When I say line fault, I am referring to a fault somewhere in the physical infrastructure from the Telco's Central Office Frame, through the telephone cable pair, to the demark terminal, past that through the building wiring, the DSL filter, to the telephone jack and actual line cord that feeds the DSL Router. I have seen problems in all these at one time or another.

The usual suspect is the cable pair. I would have your Telco make sure the telephone cable pair is clean and groomed.

(31 year LEC veteran)

Also, unless you are using MPLS or Frame end to end, once you pass the through to the WAN side of your DSL, QoS doesn't matter as the WAN traffic is best effort.


RE: VOIP/Packet Loss/ QOS & Traceroute - Don't Agree

THanks...Lower speed it is for me... Stability is key..Hopefully it won't start fluctuating again. Currently, at least, it is absolutely stable..

Thanks for the info. I can't imagine my telco doing anything on this. Their whole thing is that the speed is there...and that is as far as they go without me going crazy. They do say that they would dispatch a Tech but all they do is test back to the CO from my NIC and then blame the inside wiring which when previously tested is ok. Around and around we go.

Lower speed and good QOS for me.

Thank for the explanation.


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