31.4.5 Determining and Working with DR
If multiple IPv6 PIM-SM routers exist on the same LAN, a forwarding delegate router (DR) for the LAN is determined. The router with the highest IPv6 link-local address becomes the DR. The DR reports group-joining information from the receiving host and reports it to the rendezvous point. The DR IPv6-encapsulates multicast packets sent by the sending server, and then sends them to the rendezvous point. The following figure shows DR operation.
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![[Figure Data]](./GRAPHICS/ZU326150.GIF)
The IPv6 addresses of PIM-SM router A and PIM-SM router B are compared, and if the address of PIM-SM router B is higher, PIM-SM router B becomes the DR and reports group-joining information to the rendezvous point. Similarly, the IPv6 addresses of PIM-SM router D and PIM-SM router E are compared, and if the address of PIM-SM router E is higher, PIM-SM router E becomes the DR and forwards IPv6-encapsulated packets to the rendezvous point.