>> From Emad.Qaddoura.emadq@nt.com Mon Dec 14 17:32:19 1998
>>
>> My point was, there are so many link layers. These link layers run
>> other
>> transport than TCP and TCP would be one of the options. Do ALL of
>> these
>> link layers adapt/optimize their setting for TCP or would it be
>> easier if TCP
>> does the adaptation?
>>
>> Yes, I agree, optimizing both would be the best of all, but
>> most likely would
>> not really happen, just my opinion.
>>
I agree with you on this. I do not think making TCP-specific
changes to the link layer is the best choice (i.e., the link
layer should not have to know that the packets it is
transmitting are TCP packets).
Adapting link layer for TCP does not necessarily mean TCP-specific
adaptations. "TCP-unaware" adaptations would be more useful
(these would be unlike the TCP-aware link layer protocols that
have been proposed previously).
TCP-unaware schemes can
benefit TCP (and potentially other traffic too). To give
a trivial example, using FEC on a wireless link to reduce
the error rate may benefit TCP, without the link layer
being TCP-specific (or TCP-aware).
By the same token, if we develop some interface that specifies
to the link layer that a given packet should be retransmitted
at most X times, then the X can be chosen appropriately by the
upper layers (for instance, for audio, X may be 0,
for TCP, some non-zero number, and so on).
Again, to do this, the link layer does not have to TCP-aware.
Regards.
- nitin
>>
>>
>>
>> -----Original Message-----
>> > From: Nitin H Vaidya [SMTP:vaidya@cs.tamu.edu]
>> > Sent: Monday, December 14, 1998 1:38 PM
>> > To: Qaddoura, Emad [RICH2:IP10-M:EXCH]; pilc@lerc.nasa.gov
>> > Subject: Re: TCP over wireless type links
>> >
>> >
>> > >> From Emad.Qaddoura.emadq@nt.com Mon Dec 14 12:59:42 1998
>> > ...
>> > >> It would also be hard to imagine that many link layers will adapt to
>> > >> TCP requirements. It would
>> > >> seem more of a managable problem to have TCP adapt to different
>> > link
>> > >> behaviors. Therefore, the
>> >
>> > Can you elaborate why it is more manageable to change TCP as compared
>> > to the link layer. What if link layer adaptation is sufficient
>> > to yield decent performance - should we still adapt TCP instead?
>> > I like to think not.
>> > (granted that link layer alone may not yield optimal
>> > performance in all scenarios, but it would in some).
>> >
>> > - nitin
>>
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