H3C Technologies H3C S10500 Series Switches - Manual (Page 147)

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multicast groups and RPs. The BSR then encapsulates the RP-set in the bootstrap messages (BSMs) that it
periodically originates and floods the bootstrap messages to the entire PIM-SM domain.
Figure 43 BSR and C-RPs
Based on the information in the RP-sets, all routers in the network can calculate the location of the
corresponding RPs based on the following rules:
1. The C-RP with the highest priority wins.
2. If all the C-RPs have the same priority, their hash values are calculated through the hashing
algorithm. The C-RP with the largest hash value wins.
3. If all the C-RPs have the same priority and hash value, the C-RP that has the highest IP address wins.
The hashing algorithm used for RP calculation is “Value (G, M, C
i
) = (1103515245 * ( (1103515245 * (G
& M) + 12345) XOR C
i
) + 12345) mod 2 31 .”
Values in the hashing algorithm
Value Description
Value Hash value
G IP address of the multicast group
M Hash mask length
C
i
IP address of the C-RP
& Logical operator of “and”
XOR Logical operator of “exclusive-or”
Mod Modulo operator, which gives the remainder of an integer division