diff --git a/IMPLEMENTATION b/IMPLEMENTATION
index b75dccd337..55d16a04ca 100644
--- a/IMPLEMENTATION
+++ b/IMPLEMENTATION
@@ -2,7 +2,7 @@
 
 	KAME Project
 	http://www.kame.net/
-	$KAME: IMPLEMENTATION,v 1.262 2001/08/16 14:19:02 jinmei Exp $
+	$KAME: IMPLEMENTATION,v 1.263 2001/08/18 06:13:39 jinmei Exp $
 
 
 NOTE: The document tries to describe behaviors/implementation choices
@@ -657,7 +657,14 @@ sent from a user application as follows:
    the packet.  If it fails, the source address selection also fails.
    If the kernel can find an interface, choose the most appropriate
    address based on the algorithm described in
-   draft-ietf-ipngwg-default-addr-select-xx.txt .
+   draft-ietf-ipngwg-default-addr-select-xx.txt .  This draft allows
+   an implementation to add implementation-specific rules with higher
+   precedence than the rule "Use longest matching prefix."  KAME's
+   implementation has the following additional rule:
+   - prefer addresses on alive interfaces, that is, interfaces with
+     the UP flag being on.  This rule is particularly useful for
+     routers, since some routing daemons stop advertising prefixes
+    (addresses) on interfaces that has become down.
    Addresses that break the scope zone of the destination, or
    addresses whose zone do not contain the outgoing interface are
    never chosen.