diff --git a/pimd/TODO b/pimd/TODO
index 6ed98c0..dc2ece5 100644
--- a/pimd/TODO
+++ b/pimd/TODO
@@ -354,4 +354,7 @@
     http://www.ietf.org/internet-drafts/draft-ietf-mboned-lightweight-igmpv3-mldv2-05.txt
     http://www.ietf.org/html.charters/mboned-charter.html
 
+T41 ssmping
+    http://www.venaas.no/multicast/ssmping/
+
 -x-