Hitachi GR2000 Series Installation Manual page 287

4.14.1 Multicast relay
Please pay attention to the following points when relaying a multicast packet usi
this router.
4.14.1.1 Common to protocols
This router prepares a multicast routing entry for performing multicast
communication when the first multicast packet is received. Because the multica
packet is relayed by way of using the software until the entry is prepared, a pack
may be lost temporarily.
This router does not support the mixed system of PIM-DM, PIM-SM and DVMRP.
Therefore, use the router after unifying the multicast protocols of all the routers
(PIM-DM, PIM-SM and DVMRP).
Please take note that multicast communication may stop until the multicast rout
information is learned, if the operating system switched to the standby system by
means of operation using the duplication router, or if the IP multicast routing
program is re-actuated by charging the ip restart multicast command.