RFC 4601, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", August 2006

Note: This RFC has been obsoleted by RFC 7761

Note: This RFC has been updated by RFC 5059, RFC 5796, RFC 6226

Errata ID: 1114
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Maren Peasley
Date Reported: 2007-12-21
Held for Document Update by: David Ward
Date Held: 2009-03-22

Section 4.3.1 says:

   Before an interface goes down or changes primary IP address, a Hello
   message with a zero HoldTime should be sent immediately (with the old
   IP address if the IP address changed).  This will cause PIM neighbors
   to remove this neighbor (or its old IP address) immediately.  After
   an interface has changed its IP address, it MUST send a Hello message
   with its new IP address.  If an interface changes one of its
   secondary IP addresses, a Hello message with an updated Address_List
   option and a non-zero HoldTime should be sent immediately.  This will
   cause PIM neighbors to update this neighbor's list of secondary
   addresses immediately.

Notes:

Section 6.1.1, item 2 only considers the possibility of falsified Designated Router election results, it does not consider forged Hello messages with zero HoldTime or with altered Address_List options.

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