Pim candidate RP election policy is incorrect

[chenbaolou]

Description

The RP of a group is determined based on the RP in a BSM packet, and the address of the multicast service group is required to calculate the RP.

Version

10.2

How to reproduce

The current policy is different from that of other vendors, and the multicast stream will not work.

Expected behavior

The RP election needs to be based on the multicast address of the specific service.

Actual behavior

The RP election is based on the group address in the BSM packet.

Additional context

No response

Checklist

• I have searched the open issues for this bug.
• I have not included sensitive information in this report.

[chenbaolou]

On page 79 of the RFC4601, the hash function is based on the service multicast address instead of the group address in the BSM packet.

The hash function is used by all routers within a domain, to map a group to one of the RPs
from the matching set of group-range-to-RP mappings (this set all have the same longest
mask length and same highest priority). The algorithm takes as input the group address, and
the addresses of the candidate RPs from the mappings, and gives as output one RP address
to be used.