RFC 3782, "The NewReno Modification to TCP's Fast Recovery Algorithm", April 2004
Note: This RFC has been obsoleted by RFC 6582Source of RFC: tsvwg (tsv)
See Also: RFC 3782 w/ inline errata
Errata ID: 231
Publication Format(s) : TEXT
Reported By: Sally Floyd
Date Reported: 2004-06-07
Section 8 says:
When not in Fast Recovery, the value of the state variable "recover" should be pulled along with the value of the state variable for acknowledgments (typically, "snd_una") so that, when large amounts of data have been sent and acked, the sequence space does not wrap and falsely indicate that Fast Recovery should not be entered (Section 3, step 1, last paragraph).
It should say:
When updating the Cumulative Acknowledgement field outside of Fast Recovery, the "recover" state variable may also need to be updated in order to continue to permit possible entry into Fast Recovery (Section 3, step 1). This issue arises when an update of the Cumulative Acknowledgement field results in a sequence wraparound that affects the ordering between the Cumulative Acknowledgement field and the "recover" state variable. Entry into Fast Recovery is only possible when the Cumulative Acknowledgment field covers more than the "recover" state variable.