This section describes IPv6 multicast address to MAC address mapping and IPv6 multicast forwarding entries.
For IPv6 multicast address to MAC address mapping, Ethernet MAC addresses in the range of 33-33-00-00-00-00 to 33-33-FF-FF-FF-FF are reserved for IPv6 multicast. To map an IPv6 multicast address to a MAC-layer multicast address, the low-order 32 bits of the IPv6 multicast address are mapped directly to the low-order 32 bits in the MAC-layer multicast address.
For IPv6 multicast forwarding entries, IPv6 multicast snooping forwarding entries are based on MAC addresses, while native IPv6 multicast forwarding entries are based on IPv6 addresses. When both MLD snooping or PIM snooping for IPv6 and native IPv6 multicast are enabled on the same device, both types of forwarding entries are supported on the same forward plane, although they are used for different services.
The following output shows a service with PIM snooping for IPv6 that has received joins for two multicast groups from different sources. As the forwarding mode is MAC-based, there is a single MFIB entry created to forward these two groups.
*A:PE# show service id 1 pim-snooping group ipv6
===============================================================================
PIM Snooping Groups ipv6
===============================================================================
Group Address Source Address Type Incoming Num
Intf Oifs
-------------------------------------------------------------------------------
ff0e:db8:1000::1 2001:db8:1000::1 (S,G) SAP:1/1/1 2
ff0e:db8:1001::1 2001:db8:1001::1 (S,G) SAP:1/1/1 2
-------------------------------------------------------------------------------
Groups : 2
===============================================================================
*A:PE#
*A:PE# show service id 1 all | match "Mcast IPv6 scope"
Mcast IPv6 scope : mac-based
*A:PE#
*A:PE# show service id 1 mfib
===============================================================================
Multicast FIB, Service 1
===============================================================================
Source Address Group Address Port Id Svc Id Fwd
Blk
-------------------------------------------------------------------------------
* 33:33:00:00:00:01 sap:1/1/1 Local Fwd
sap:1/1/2 Local Fwd
-------------------------------------------------------------------------------
Number of entries: 1
===============================================================================
*A:PE#