Re: [Bloat] Skype

[Matt Mathis <mattmathis@google.com>]

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BTW  Be aware that skipe tries multiple strategies to get connectivity.
Skype in one environment may be using a totally different protocol (with
different dynamics) than another.

(Either TCP or UDP, with lots of middle box traversal options: STUN, etc)

Thanks,
--MM--
The best way to predict the future is to create it.  - Alan Kay

Privacy matters!  We know from recent events that people are using our
services to speak in defiance of unjust governments.   We treat privacy and
security as matters of life and death, because for some users, they are.


On Mon, Nov 19, 2012 at 5:25 AM, Michael Welzl <michawe@ifi.uio.no> wrote:

> Ohh... rats, I didn't check that. Quite possible.
>
> Cheers,
> Michael
>
>
>
> On Nov 19, 2012, at 11:27 AM, Ingemar Johansson S wrote:
>
>  Hi
>>
>> Been a year or so since I read about the inner secrets of Skype so this
>> may be old..
>> I would suspect that your Skype session runs over TCP (via a Relay). This
>> may happen e.g when a firewall blocks UDP.
>> TCP (possibly in combination with a lossy WiFi connection) is what
>> creates the high latencies.
>>
>> /Ingemar
>> ------------------------------
>>
>> Message: 2
>> Date: Sun, 18 Nov 2012 15:57:53 +0100
>> From: Michael Welzl <michawe@ifi.uio.no>
>> To: bloat <bloat@lists.bufferbloat.NET>
>> Subject: [Bloat] Skype
>> Message-ID: <647D57F5-24CE-4006-AD2A-**74141C84C3CB@ifi.uio.no<647D57F5-24CE-4006-AD2A-74141C84C3CB@ifi.uio.no>
>> >
>> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>>
>> Hi,
>>
>> I have repeatedly noticed that Skype sometimes, in a long conversation
>> involving video, can create massive audio delays (in the order of multiple
>> seconds). This has happened to me in a conversation from a hotel room in
>> the US to my home in Oslo (where, apologies, I haven't yet looked into
>> de-bloating my modem and access point), and from my office in Oslo to
>> someone else's office in the US.
>>
>> I'm wondering: was that always due to bloated equipment along the path
>> (including the end hosts), or does Skype poorly handle its internal buffers?
>>
>> Any experiences? I suppose the way to find out is to run Skype over a
>> verifiably de-bloated path. If, then, the problem never occurs, the fault
>> is with the equipment and not with Skype (and vice versa).
>>
>> Cheers,
>> Michael
>>
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Sun, 18 Nov 2012 08:09:03 -0800 (PST)
>> From: Alex Burr <ajb44.geo@yahoo.com>
>> To: bloat <bloat@lists.bufferbloat.NET>
>> Subject: Re: [Bloat] Skype
>> Message-ID:
>>         <1353254943.93761.**YahooMailNeo@web126202.mail.**ne1.yahoo.com<1353254943.93761.YahooMailNeo@web126202.mail.ne1.yahoo.com>
>> >
>> Content-Type: text/plain; charset=us-ascii
>>
>> I have noticed delays - although I don't think multiple seconds - but I
>> think that it may be skype trying to make the best of a bad connection. I
>> don't have any knowledge of the internals of the skype client, but I
>> suspect that they take the view that delayed audio is better than
>> incomprehensible audio - I think I have even heard it actually repeating
>> the last bit of audio before a glitch, to give you a better chance to
>> understand the next bit, and presumably catching up when the opportunity
>> arises.
>>
>> So, an experiment to rule out skype might need to use not just a
>> de-bloated path, but one with known packet loss.
>>
>>
>> Alex
>>
>>
>>
>> ----- Original Message -----
>>
>>> From: Michael Welzl <michawe@ifi.uio.no>
>>> To: bloat <bloat@lists.bufferbloat.NET>
>>> Cc:
>>> Sent: Sunday, November 18, 2012 2:57 PM
>>> Subject: [Bloat] Skype
>>>
>>> Hi,
>>>
>>> I have repeatedly noticed that Skype sometimes, in a long conversation
>>> involving video, can create massive audio delays (in the order of
>>> multiple seconds). This has happened to me in a conversation from a
>>> hotel room in the US to my home in Oslo (where, apologies, I haven't
>>> yet looked into de-bloating my modem and access point), and from my
>>> office in Oslo to someone else's office in the US.
>>>
>>> I'm wondering: was that always due to bloated equipment along the path
>>> (including the end hosts), or does Skype poorly handle its internal
>>> buffers?
>>>
>>> Any experiences? I suppose the way to find out is to run Skype over a
>>> verifiably de-bloated path. If, then, the problem never occurs, the
>>> fault is with the equipment and not with Skype (and vice versa).
>>>
>>> Cheers,
>>> Michael
>>>
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>>> Bloat@lists.bufferbloat.net
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>>>
>>>
>>
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>> End of Bloat Digest, Vol 23, Issue 10
>> ***************************************
>>
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