R3303-HP HSR6800 Routers IP Multicast Configuration Guide

319
Figure 91 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
".
Table 12 Values in the hashing algorithm
Value Descri
p
tion
Value Hash value.
G
The digest from the exclusive-or (XOR) operation between the 32-bit segments of the IPv6
multicast group address. For example, if the IPv6 multicast address is
FF0E:C20:1A3:63::101, G = 0xFF0E0C20 XOR 0x01A30063 XOR 0x00000000
XOR 0x00000101.
M Hash mask length.
C
i
The digest from the exclusive-or (XOR) operation between the 32-bit segments of the C-RP
IPv6 address. For example, if the IPv6 address of the C-RP is 3FFE:B00:C18:1::10, C
i
=
0x3FFE0B00 XOR 0x0C180001 XOR 0x00000000 XOR 0x00000010.
& Logical operator of "and".
XOR Logical operator of "exclusive-or".
mod Modulo operator, which gives the remainder of an integer division.
Embedded RP
The embedded RP mechanism enables a router to resolve the RP address from an IPv6 multicast address
so that the IPv6 multicast group is mapped to an RP. This RP can take the place of the statically configured
RP or the RP dynamically calculated based on the BSR mechanism. The DR does not need to learn the RP
address beforehand. The specific process is as follows.