RFC 4960, "Stream Control Transmission Protocol", September 2007
Note: This RFC has been obsoleted by RFC 9260Source of RFC: tsvwg (tsv)
See Also: RFC 4960 w/ inline errata
Errata ID: 3788
Publication Format(s) : TEXT
Reported By: Karen Nielsen
Date Reported: 2013-11-06
Verifier Name: Martin Stiemerling
Date Verified: 2014-01-13
Section 8.1 says:
An endpoint shall keep a counter on the total number of consecutive retransmissions to its peer (this includes retransmissions to all the destination transport addresses of the peer if it is multi-homed), including unacknowledged HEARTBEAT chunks.
It should say:
An endpoint shall keep a counter on the total number of consecutive retransmissions to its peer (this includes data retransmissions to all the destination transport addresses of the peer if it is multi-homed),including the number of unacknowledged HEARTBEAT chunks observed on the path which currently is used for data transfer. Unacknowledged HEARTBEAT chunks observed on paths different from the path currently used for data transfer shall not increment the association error counter, as this could lead to association closure even if the path which currently is used for data transfer is available (but idle).
RFC4960 Endpoint Failure detection mechanism is deficient in that
HB failures on some failing paths may take the association down, even
if other paths are working perfectly, but simply at the time no data
or HBs are being sent on the working paths.
The situation occurs when the association is idle
(no data is being transmitted) and the HBI settings on
the failing paths are much more aggressive than the HBI
set on the working paths. RFC6458 allows for specification
of the HBI on a per destination address whereby
such in-homogeneous setting of the HBI can occur.
The solution proposed to the issue is to demand that
HB failures observed on paths different from the path
currently used for data transfer do
not contribute to the association error counter.
HB failures observed on the path currently used for
data transfer, when this path is idle,
shall contribute to the association error counter.
Thereby supporting Endpoint Failure detection when the
association is idle. When the association is transmitting data,
the fate of the data transmissions and retransmissions
will serve to instantiate Endpoint Failure detection.