Installing and Administering LAN/9000 Software

Chapter 6 139
Network Addressing
IP Multicast Addresses
multicast address 01-00-5E-00-00-00 (hex). Ethernet multicast
addresses can be in the range 01-00-5E-00-00-01 through
01-00-5E-7F-FF-FF.
NOTE Several IP multicast addresses may share the same Ethernet multicast
address because the IP multicast address has 28 significant bits.
Multicast Routing
Multicast datagrams are sent through the interface associated with the
default route. If that interface does not support multicast, attempts to
send multicast datagrams will result in the ENETUNREACH error.
A default multicast route can be configured by specifying a network
route for 224.0.0.0. The example below provides both the command line
and netconf file entries.
route add 224.0.0.0 192.1.2.3 0 #192.1.2.3 is a local interface
ROUTE_DESTINATION[1]=”224.0.0.0”
ROUTE_GATEWAY[1]=”192.1.2.3”
ROUTE_COUNT[1]=”0”
Additionally, routes for specific multicast addresses can be configured
just like any other host route. The example below provides both the
command line and netconf file entries.
route add 224.1.2.3 192.5.6.7 0 #192.5.6.7 is a local interface
ROUTE_DESTINATION[2]=”224.1.2.3”
ROUTE_GATEWAY[2]=”192.5.6.7”
ROUTE_COUNT[2]=”0”