diff --git a/pimd/WHY_SSM b/pimd/WHY_SSM
index a846971..6ff8f13 100644
--- a/pimd/WHY_SSM
+++ b/pimd/WHY_SSM
@@ -6,19 +6,32 @@
 - SSM consumes minimum link bandwidth
 - SSM simplifies multicast address management (specially important for
   inter-domain multicast)
+  - SSM (S,G) channels easily provide unique per-application addressing
+  - SSM does not require MSDP between PIM domains
 - SSM does not suffer instabilities from traffic-driven SPT switchover
+- SSM is not suscetible to DoS attack from unwanted sources
 - SSM does not use RP. Some RP issues:
   - RP is possible point of failure
   - RP demands redundancy management
   - RP may require PIM dense mode support for RP election
   - RP is possible performance bottleneck
   - RP may demand lots of extra management
+- SSM can be deployed in an existing PIM SM network (only the last hop
+  routers need to support IGMPv3)
+- SSM is easier to deploy and maintain
 
 PIM-SSM drawbacks
 -----------------
 
-- SSM requires IGMPv3 support on receivers
+- SSM requires IGMPv3 support on both receivers and last-hop routers
 - SSM may be memory intensive when managing (S,G) states for
   many-to-many multicast distribution
+- SSM will keep (S,G) state as long as there are subscriptions from
+  receivers, even if the source is not actually sending traffic
+
+Cisco Documentation for SSM Benefits
+------------------------------------
+
+http://www.cisco.com/c/en/us/td/docs/ios/12_2/ip/configuration/guide/fipr_c/1cfssm.html#wp1000969
 
 --EOF--