pimd: Cisco Documentation for SSM Benefits
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--