RFC 6204, "Basic Requirements for IPv6 Customer Edge Routers", April 2011

Note: This RFC has been obsoleted by RFC 7084

Errata ID: 3054
Status: Verified
Type: Technical
Publication Format(s) : TEXT
Reported By: Tore Anderson
Date Reported: 2011-12-16
Verifier Name: ron bonica
Date Verified: 2012-01-03

Section 4.3 says:

   L-13:  If the delegated prefix changes, i.e., the current prefix is
          replaced with a new prefix without any overlapping time
          period, then the IPv6 CE router MUST immediately advertise the
          old prefix with a Preferred Lifetime of zero and a Valid
          Lifetime of the lower of the current Valid Lifetime and 2
          hours (which must be decremented in real time) in a Router
          Advertisement message as described in Section 5.5.3, (e) of
          [RFC4862].

It should say:

   L-13:  If the delegated prefix changes, i.e., the current prefix is
          replaced with a new prefix without any overlapping time
          period, then the IPv6 CE router MUST immediately advertise the
          old prefix with a Preferred Lifetime of zero and a Valid
          Lifetime of either a) zero, or b) the lower of the current
          Valid Lifetime and 2 hours (which must be decremented in real
          time), in a Router Advertisement message as described in
          Section 5.5.3, (e) of [RFC4862].

Notes:

The original text in L-13 prohibits implementers from transmitting Valid Lifetime = 0 whenever a prefix needs to be invalidated. It should not, because transmitting VL=0 is easier to implement than sending "the lower of the current Valid Lifetime and 2 hours (which must be decremented in real time)".

Transmitting Valid Lifetime = 0 has the exact same effect on a host as the procedure described in the original text, i.e., it will the host to lower (but never raise) the remaining valid lifetime to 7200 seconds.

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