Subject: draft-ietf-pilc-asym-00.txt comments/questions

From: Jan Kullander <[email-masked]>
Date: Thu, 7 Oct 1999 11:08:50 +0200

http://www.ietf.org/internet-drafts/draft-ietf-pilc-asym-00.txt

I have a few questions/comments especially on Ack Reconstruction.

2.  I can think of several combinations of broadcast networks and 
cellular networks in which the "forward direction" introduces higher
latency and error rates. The remedies suggested in chapter 5 are 
not limited to access links with "better link characteristics" in the 
forward direction, so maybe these basic assumptions could be 
dropped.

5.1.1 Does RFC XXX translate to 2507 "IP Header Compression" by
Degermark, Nordgren and Pink?

5.1.4 I assume there is a typo in the third paragraph second sentence. 
The receiver receives a (data?) packet with ECN-Echo flag set.

5.1.5 Isn't there a risk for data packet starvation in the ACKs first 
scheme? (I believe you mentioned that in earlier work).

This method is a suggested addition to the draft to decrease the ACK 
delay when large data segments compete for the link resource:

If a single data packet in one flow occupies the reverse link for an 
intolerable length of time, the link layer can split it and let smaller 
packet(s) from other flow(s) pass. (Not with IP fragmentation of course).

5.2.2 ACK Reconstruction

I do not understand how the reconstructor deducts the segment size used
by the sender. If the size is underestimated, the reconstructor sends too 
many ACKs and hence induce an overly aggressive connection.

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Jan Kullander
Ericsson Mobile Data Design AB