MOSPF vs OSPF: Source and Destination Impact

[kususe]

In the Rfc about MOSPF, is declared that one difference between this alghortim an his "unicast version" OSPF that, while in the former what is important is both the source and the destination, in OSPF what is fundamental is just the destination.
Why this statement, if in both case source is the initial point where shortest path begins?
Thanks in advance.

 

[Greg Bernhardt]

In the Rfc about MOSPF, is declared that one difference between this alghortim an his "unicast version" OSPF that, while in the former what is important is both the source and the destination, in OSPF what is fundamental is just the destination.
Why this statement, if in both case source is the initial point where shortest path begins?
Thanks in advance.

Honestly I think you are better off finding a Cisco/Network forum as this question is fairly technical.

 

[jobyts]

In multicast routing each node has to form a distribution tree based on the source node. The tree is unique to each source node, so that a node receiving a multicast packet knows exactly which all node have received the packet and exactly where to forward the packet. Or loops could form.