Re: PILC: prioritization

From: Vincent Magret (vincent.magret@aud.alcatel.com)
Date: Thu Jan 28 1999 - 17:02:52 EST


Hi

Just to put an idea in the discussion.

may be we could think of having a sort of cache mechanism, where the receiver
caches the current connections (quadruplet src/dst address/port). If the packet is
coming from a valid source then use the mechanims described in the previous mail
related to this topic otherwise just behave as usual.

Vincent.
Alcatel USA.

John Border wrote:

> > Second, I've been considering writing up a new type of SACK option.
> > The specific idea I had was to make one which I jokingly call a CRACK
> > (CoRruption ACK) for specific use with wireless. Receivers should, in
> > principle, be able to detect packets with failed checksum and send
> > back a CRACK indicating to the sender that a packet has been dropped,
> > but it is not a sign of congestion -- retransmit the packet but don't
> > reduce cwnd.
>
> We've looked at this concept from time to time over the years. One issue you
> have to deal with is that if the checksum fails, can you trust the fields in
> the packet you use to identify the sender of the packet. There is risk
> associated with assuming that you can and that risk is different for different
> types of links. (For example, with an older implementation of our spacelink
> "MAC", errors tended to occur towards the end of packets because of the way our
> forward error correction worked. Our newer encoding is much better at
> correcting errors but encoding includes spreading the bits around so errors
> which can't be corrected can be anywhere in the packet.)
>
> John Border
> Hughes Network Systems



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