RFC Errata
RFC 2439, "BGP Route Flap Damping", November 1998
Source of RFC: idr (rtg)
Errata ID: 3964
Status: Rejected
Type: Technical
Publication Format(s) : TEXT
Reported By: Gunjan Bansal
Date Reported: 2014-04-15
Rejected by: Alia Atlas
Date Rejected: 2014-05-07
Section 4.8.2 says:
In either case then: 1. set t-updated = t-now 2. insert into a reuse list (see Section 4.8.6)
It should say:
In either case then: 1. set t-updated = t-now
Notes:
The route which is unreachable should NOT be inserted into the reuse-list. reuse-list (as per explanation in Section 4.8.7) is used for fast evaluation of routes which have been suppressed long enough and can be potentially used again. The "unreachability/withdrawal" of route is never suppressed and never needs to be re-evaluated in future.
--VERIFIER NOTES--
RFC 2439 isn't the easiest to read, but this erratum is not correct. Despite its name, the "reuse list" as described in S. 4.8.7 is used for processing timer-driven events in general, including freeing up damping structures ("histories"). Quoting from S. 4.8.7, "Handling Reuse Timer Events":
all of the routes in the first queue will be
available for immediate reuse if reachable or the history entry could
^^^^^^^^^^^^^^^^^^^^^^^^^^
be disposed of if unreachable.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
If you have any doubt that "history" means "damping structure", take a look at S. 4.8.2:
If there is no previous stability history (the damping structure
pointer is zero), then:
Presumably, you're clear on why histories for unreachable routes need to be maintained to begin with.