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node from the outgoing interface list and determines whether it has receivers for that IPv6 multicast group. 
If not, the router continues to forward the prune message to its upstream router.  
Multicast source registration 
The purpose of IPv6 multicast source registration wi ll inform the RP about the existence of the IPv6 
multicast source. 
Figure 95  IPv6 multicast source registration 
 
 
As shown in Figure 95, the IPv6 mu lticast source registers with the RP as follows:  
1. The IPv6...

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receiver side. The RP acts as a transfer station for all IPv6 multicast packets. The whole process involves 
the following issues:  
•  The DR at the source side and the RP need to implement complicated encapsulation and 
de-encapsulation of IPv6 multicast packets.  
•   IPv6 multicast packets are delivered along a  path that might not be the shortest one. 
•   An increase in IPv6 multicast traffic heavily burdens the RP, increasing the risk of failure.  
To solve the issues, IPv6 PIM-SM allows an...

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•  RP discovery 
•   DF election 
•   Bidirectional RPT building 
Neighbor discovery 
IPv6 BIDIR-PIM uses the same neighbor discovery mechanism as IPv6 PIM-SM does. For more information, 
see  Neighbor discovery .  
RP discovery 
IPv6 BIDIR-PIM uses the same RP discovery mechanism as IPv6 PIM-SM does. For more information, see 
RP discovery .
  
In IPv6 PIM-SM, an RP must be specified with a real IPv6 address. In IPv6 BIDIR-PIM, however, an RP can 
be specified with a virtual IPv6 address, which is...

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1.
 
Router B and Router C multicast DF election messa ges to all PIM routers (224.0.0.13). The election 
messages carry the RP’s address, and the priority  and metric of the unicast route, MBGP route, or 
multicast static route to the RP.  
2.  The router with a route of the highest priority becomes the DF.  
3. In the case of a tie, the router with the route with the lowest metric wins the DF election.  
4. In the case of a tie in the metric, the router  with the highest link-local IPv6 address...

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Figure 98 RPT building at the multicast source side 
 
 
As shown in Figure 98, the  process of building a source-side RPT is relatively simple:  
1. When an IPv6 multicast source sends IPv6 multicas t packets to IPv6 multicast group G, the DF in 
each network segment unco nditionally forwards the packets to the RP.  
2. The routers along the path from the source’s directly  c o n n e c t e d  r o u t e r  t o  t h e  R P  f o r m  a n  R P T  b r a n c h .  
Each router on this branch adds a (*,...

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IPv6 admin-scope zones correspond to IPv6 multicast groups with different scope values in their group 
addresses. The boundary of the IPv6 admin-scope zone is formed by zone border routers (ZBRs). Each 
IPv6 admin-scope zone maintains one BSR, which serves multicast groups within a specific scope. IPv6 
multicast protocol packets, such as assert messages and bootstrap messages, for a specific group range 
cannot cross the IPv6 admin-scope zone boundary. IPv6 multicast group ranges served by...

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Figure 100 IPv6 multicast address format 
 
 
The admin-scope zone range increases with the value of the Scope field. For example, value E 
indicates IPv6 global scope, which contains other admin-scope zones with the Scope field values 
smaller than E. Possible values of the Scope field are given in  Table 2.  
Table 2  Values of the 

Scope field 
Value Meanin
g Remarks 
0, F  Reserved  N/A 
1 Interface-local  scope N/A 
2 Link-local scope N/A 
3 Subnet-local scope  IPv6 admin-scope zone 
4...

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Neighbor discovery 
IPv6 PIM-SSM uses the same neighbor discovery mechanism as in IPv6 PIM-SM. For more information, 
see Neighbor discovery .  
DR election 
IPv6 PIM-SSM uses the same DR election mechanism as in IPv6 PIM-SM. For more information, see  DR 
ele
ction . 
SPT building 
The decision to build an RPT for IPv6 PIM-SM or an SPT for IPv6 PIM-SSM depends on whether the IPv6 
multicast group that the receiver will join falls into the IPv6 SSM group range. The IPv6 SSM group range 
that IANA...

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Relationships among IPv6 PIM protocols 
In an IPv6 PIM network, IPv6 PIM-DM cannot work with IPv6 PIM-SM, IPv6 BIDIR-PIM, or IPv6 PIM-SSM. 
However, IPv6 PIM-SM, IPv6 BIDIR-PIM, and IPv6 PIM-SSM can work together. When they work together, 
which one is chosen for a receiver trying to join a group depends, as shown in  Figure 102.  
Figure 102  Relationships 

among IPv6 PIM protocols 
 
 
For more information about MLD SSM mapping, see Configuring MLD (available only on the HP 5500 
EI)
....

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Task  Remarks 
Enabling IPv6 PIM-DM  Required
 
Enabling state-refresh capability  Optional
 
Configuring state refresh parameters  Optional
 
Configuring IPv6 PIM-DM graft retry period  Optional
 
Configuring IPv6 PIM common features  Optional
 
 
Configuration prerequisites 
Before you configure IPv6 PIM-DM, complete the following tasks: 
•  Enable IPv6 forwarding and configure an IPv6 unic ast routing protocol so that all devices in the 
domain are interoperable at the network layer. 
•...