Subject: [rohc] (no subject)

From: "william zheng" <[email-masked]>
Date: Fri, 15 Nov 2002 07:09:15 +0000

Hi All,

As for draft-ietf-rohc-tcp-enhancement-00,

I have one simple question about the description on Page 11 as follows.

" If the number of the compress packets been send gets larger than w(...) = K*MAX (MAX(cwnd_seq, 2*ssthresh_seq), ...), the comression transits to CO state. "

In the definition of w(...), we know it should be expressed in bytes since cwnd_seq and ssthresh_seq are both in bytes. Therefore, I think it may be necessary to refine the description.(??)

Another question is that in the tracking algo.(SEQ), it seems that TCP sequence number is assumed to be of non-wrap-around. (??) But in fact, TCP ISN (initial sequence number) is very possibly random, which may cause TCP sequence number wraparound even without a long time span. (??)

Just refine it as

-Slow start

*if ((NSN > CMAXSN and (NSN - CMAXSN) < MAXSN_JUMP) or (NSN < CMAXSN and (CMAXSN - NSN) >MAXSN_JUMP)), (MAXSN_JUMP can be defined as e.g 2^31), increase cwnd by the distance (abs (NSN - CMAXSN)) mod (2^32-1), and update based on the following rules:

CMAXSN = NSN;

if ((CMAXSN - CMINSN) mod (2^32-1) > cwnd)

CMINSN = (CMAXSN - cwnd) mod (2^32-1);

*...

-CONGESTION AVOIDANCE

*same as the above-mentioned.

-FAST RECOVERY

*if NSN >= (CMAXSN + cwnd) mod (2^32-1) ...

Best Regards,
William

STOP MORE SPAM with the new MSN 8 and get 2 months FREE*
_______________________________________________
Rohc mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/rohc