ecn info

Crist J. Clark cristjc at
Mon Dec 1 17:27:05 PST 2003

On Mon, Dec 01, 2003 at 12:18:02AM -0500, Kenneth W Cochran wrote:
> Where might I find information on how FreeBSD handles
> ECN (explicit congestion notification)?
> I've been searching the mailing list archives & so far
> can't find anything.

AFAIK, there isn't much to find. There is some code for 
housekeeping of the ECT and CE bits in the DIFSERV field, but what may
be most telling is,

  $ cd /usr/src/sys
  $ fgrep -r TH_ECE net*
  netinet/tcp.h:#define   TH_ECE  0x40
  netinet/tcp.h:#define   TH_FLAGS        (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)

The CWR flag gets the same result. They are not actually used
Crist J. Clark                     |     cjclark at
                                   |     cjclark at    |     cjc at

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