| WHY SSM |
| |
| Benefis of PIM SSM over PIM SM |
| ------------------------------ |
| |
| - 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 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 |
| |
| --EOF-- |