Re: about TURN MAGIC-COOKIE

I do not think it is necessary to inspect data packets and, if it is
found that they contain the magic cookie string, wrap them in a DATA
attribute in a SEND.

The magic cookie is a random 32 bit string. The probability of it
appearing in a data packet is approximately 1 in 4 billion. If that
probability is still too large, then we should just increase the size of
the magic cookie. However, 1 in 2 billion is likely much smaller than
the packet loss rate of the underlying network. A mis-clasification in
TURN would manifest itself as a packet loss. Since this packet loss rate
is less than the network packet loss rate, I don't see a real issue.

Thanks,
Jonathan R.

Kenneth Ho wrote:

> Toshihiro Sonoda wrote:
> 
> 
>>>Toshihiro Sonoda wrote:
>>>
>>>
>>>>Why can a server disambiguate a TURN Request from a data packet by
>>>>looking for the MAGIC-COOKIE attribute, as described in Section 7.2.3.
>>>>
>>>>Can it guarantee that UDP packets of non-TURN Packets doesn't have
>>>>same value as MAGIC-COOKIE.
>>>>
>>>>
>>>
>>>My take is a TURN client library would need to inspect every packet
>>>before sending them to a TURN server.
>>>If a packet happens to have something resembling a magic-cookie, the
>>>library would have to wrap it in a SEND request.
>>
>>
>>If a packet from client to turn server happens to have something
>>resembling a magic-cookie, then the packet would have to be wrapped
>>using SEND request.
>>I understand that.
>>
>>but, if a packet form turn server to client happens to have something
>>resembling a
>>magic-cookie, then should turn server wrap the packet using any
>>turn-request or response?
> 
> 
> You could wrap that packet in a DATA indication to client.
> 
> 
>>
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> 
> 
> 
> 
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Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Director, Service Provider VoIP Architecture   Parsippany, NJ 07054-2711
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