Sun Microsystems 1.0 - Manual (Page 105)

FDDI Network Topologies 79
7
Mixed FDDI/Ethernet Networks
This section concentrates on the implementation of mixed FDDI/Ethernet
networks. The same principles could be applied to mixed FDDI/802.3 and
mixed FDDI/802.5 (Token Ring) networks. FDDI and Token Ring networks are
based on a ring topology; Ethernet and 802.3 networks are based on a bus
topology.
FDDI/Ethernet IP Router
The machines at the boundaries between the FDDI and Ethernet networks in
the following examples are assumed to be Ultra systems that have at least one
SunFDDI/P interface and one Ethernet interface installed. These machines
operate as IP routers.
Special software is not required. The combination of the SunFDDI/P driver
and the SunOS IP routing implementation handles the routing and relaying of
packets between FDDI and Ethernet stations. Note that the packets on the
FDDI ring can be as long a 4500 octets, whereas Ethernet packets are restricted
to a maximum of 1500 octets.
Figure 7-7 illustrates the basic topology of a mixed FDDI/Ethernet network.
In this example, there are two FDDI/Ethernet IP routers that represent the
boundaries between the three networks.