RFC 7761, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", March 2016Source of RFC: pim (rtg)
See Also: RFC 7761 w/ inline errata
Errata ID: 5342
Publication Format(s) : TEXT
Reported By: Frank Hua Li
Date Reported: 2018-04-28
Verifier Name: Alvaro Retana
Date Verified: 2018-05-24
Section 4.4.2 says:
set KeepaliveTimer(S,G) to RP_Keepalive_Period;
It should say:
set KeepaliveTimer(S,G) to max(Keepalive_Period, RP_Keepalive_Period);
The normal keepalive period for the KAT(S,G) defaults to 210 seconds. However, at the RP, the keepalive period must be at least the Register_Suppression_Time, or the RP may time out the (S,G) state before the next Null-Register arrives. Thus, the KAT(S,G) is set to max(Keepalive_Period, RP_Keepalive_Period) when a Register-Stop is sent.
Note that the text above comes from §4.11.