RFC 1490 359
Figure 10-19
Frame Relay Hub and Spoke
You can, however, disable split horizon with Cisco's EIGRP protocol.
NOTE
Notice that in the frame connections, all the addresses are on the same subnet because this is a
multipoint network.
TIP
OSPF does not apply split horizon, so it does not have to be disabled in partial-mesh
configurations. Because it is a link-state protocol, you don't need to disable it.
Subinterfaces
Another solution to the split-horizon problems is to create subinterfaces. A subinterface is a
logical interface in the IOS. It is treated very much like a physical interface. In Figure 10-20,
Serial 0.100 is a subinterface and is configured as a point-to-point circuit. Interface Serial 0.200
is also a point-to-point circuit to Router C. You can add logical interfaces to the physical
interfaces on the router because you need them. The code in the router treats them as point-to-
Router B
multipoint interface
DLCI 103
DLCI 102
Cloud
DLCI 200
Router C
Router A
192.168.1.3
Network 300
Network 100
Network 200
192.168.1.2
DLCI 300
87200333.book Page 359 Wednesday, August 22, 2001 2:53 PM