Has VoIP (Skype) been affected by the updated traffic management profiles?

[#1]

I've noticed over recent days that VoIP traffic, specifically Skype, is suffering a significant amount of packet loss, high latency and dropped calls. Normally Skype is absolutely rock solid for me with almost no packet loss (<1%) and low latency (<30ms) during both Skype to Skype calls and SkypeIn/SkypeOut (via POTS) calls.
PlusNet recently updated their traffic management system (to better cope with iPlayer demand), but I'm wondering if whatever has changed has also affected Skype.
Has anyone else experiencing similar issues over the last few days?
I've done all the usual troubleshooting things, such as rebooting my laptop, wireless router and ADSL modem. I have noticed that my downstream noise margin is very slightly lower than I remember it being, but it's still generally 7-8 dB with very occasional instances of 6 dB or 9 dB (it used to average about 1 dB above than this, i.e. 8-9 dB). I can't see how this would be a factor as my sync speed (currently 8064 kbps) has been stable for a long, long time.

[#2]

Hmm.  I don't believe that any of our recent changes would have impacted VoIP traffic at all.
Would you mind doing a wireshark capture whilst trying to make a call so that we can see if the traffic is being prioritised accordingly?

[#3]

Mmmm, I've never used Wireshark before. I've just downloaded the Mac OS X version and fired it up (via X11). Wow! I think it will take me more time than I have just now to get Wireshark set up. Leave that one with me...
In the meantime, I've noticed (via the excellent RouterStats) that my noise margin dropped suddenly by 2 dB (see attached graph). Is this normal? Could it be indicative of some intermittent line fault?

[#4]

Hiya,
Hopefully this video guide might help
http://www.plus.net/support/broadband/troubleshooting/wireshark_mac_video.shtml

[#5]

OK, I've managed to figure out how to use Wireshark to capture all traffic to and from the port I have set for Skype (so all other traffic is excluded). I assume such filtering is appropriate?
To my uneducated eye, it appears that most of the incoming UDP packets do have a "Differentiated Services Field" (dsfield) of 0xa0, which suggests they're classed as Titanium. However, none of the TCP traffic has a dsfield of 0xa0 -- is this to be expected? Also, none of the outgoing packets had the sdfield set to anything other than 0x00. I assume this is expected because no prioritisation is applied until packets get to your network?
Is it safe to post the Wireshark capture file here on the forum (i.e. would it contain any "confidential" information?), or should I raise a ticket and include it there?
In any case, maybe traffic prioritisation isn't the issue.
I looked again at my noise margin and it jumped up significantly for no apparent reason (see attached graph). Again, is this normal?

[#6]

You can't post the capture on here, it is not a supported format.
Raise a ticket and attach it to that.

[#7]

You're spot on regarding the outgoing packets as you're capturing them before we see them, if you were looking at the packets from the recipient's side you'd see the priority the other way round (assuming they were still present).
Wireshark will capture anything you are doing at the time so if you are sending/receiving anything over plain text at the time (e.g. POP3 email) then that content would get saved in the Wirehark file. Anything encrypted (e.g. HTTPS) would just show as lots of random characters.
None of the changes we've made in the last couple of weeks should have affected Skype, but I can't say that it's not possible. Looking at the traffic graphs there's no change showing in the amount of VoIP traffic and the traffic showing as 0xa0 in the capture would back that up (last month's graph attached).
Have you checked to make sure you have the latest version of the software? I don't really use Skype very often so whenever I do tend to find there's a new build of the client available to download so worth a check.

[#8]

Hi Dave, James & Matt (and anyone else with an idea)
I have a similar customer issue with Skype.  Here goes the story so far.  Once upon a time . . .
Customer bought Acer Extensa 5635Z Laptop with Vista (spit).  All setup by me with all Windows updates and AVG Internet Security installed.  She uses Virgin Internet via ADSL for broadband.  Sold her Netgear DG834G V4 router with latest firmware.
Internet works fine, no problems with wifi.  Skype impossible to use with video to her parents in Australia.  They can see and hear her but she can't see or hear them.  I could see and hear her but she couldn't see or hear me very well at all (Business Premier Account).  So I did the following for her.
Sent replacement router and filters.  No change
Plugged in master socket.  No change.
Hard wired laptop to router and disabled wireless.  No change
Had laptop back, tested it on other PlusNet accounts, one with 1.2Mb link, still works fine, one 8mb still fine.
Swapped out the laptop for her.  Worked fine my end.  Sent it back to her.  Jumpy video.
Switched ISP from Virgin to PlusNet.  No change (well slightly better to me, but then that's PN to PN)
Upgraded Skype to 4.2 Beta with all the other guages that show you if anything going wrong.  Internet goes orange/little red.  My end started orange then went green.
Tried her parents different times of the day.  No change.
She took laptop to her brothers house, worked perfectly.  Came back home.  Doesn't work.
At this point, I have no bleeding idea as to what is going on.  I have already attached wireshark to her account but someone said nothing wrong.  Maybe an expert eye is needed.  She is on PlusNet Premium at present. PM me PN if you want the account username.
Thanks
Ben Cooper
Source IT

[#9]

couple of points,  James no longer works for PN.
is "She" on Virgin or PN, surely not both

[#10]

pierre, read it again

Quote

Switched ISP from Virgin to PlusNet.  No change (well slightly better to me, but then that's PN to PN)

Ben - a wireshark capture as above will say whether it is been prioritised correctly or not, but I'm unaware of any changes lately.
One option could be that her line doesn't synch high enough and / or has a line fault.
Have you checked synch speeds etc?

[#11]

Wireshark sent to PN and they said nothing there.  Sync's at over 5000kbps and PN said not line fault.

[#12]

Certainly seems a difficult one

Quote

Internet goes orange/little red.

That would seem to be the issue if yours goes green. Though I haven't used skype in a couple of years.

[#13]

Is it worth setting up a standard SIP client, at least between her laptop & you, to see if the problem is confined to Skype, or if VoIP in general is affected?
Clutching at straws here.