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Frame Relay Configuration 561
No mapping statements were required for the configuration in Example 8-14 through Example
8-18 because Inverse ARP is enabled on the multipoint subinterfaces by default. The point-to-
point subinterfaces do not require mapping statements because after the outgoing subinterface
is identified, there is only one possible router to which to forward the frame.
Router A is the only router using both multipoint and point-to-point subinterfaces. On Router
A's serial 0.1 interface, multipoint is in use, with DLCIs for Router B and Router C listed. On
Router A's other two subinterfaces, which are point-to-point, only a single DLCI needs to be
listed. In fact, only one frame-relay interface-dlci command is allowed on a point-to-point
subinterface because only one VC is allowed. Otherwise, the configurations between the two
types are similar.
Example 8-19 shows the results of the Inverse ARP and a copy of the debug frame-relay
events showing the contents of the Inverse ARP. The debug on Example 8-19 provides some
insight into Inverse ARP operation.
Example 8-18
Router E Configuration
hostname RouterE
!
ipx routing 0200.eeee.eeee
!
interface serial0
encapsulation frame-relay
!
interface serial 0.1 point-to-point
ip address 140.1.3.5 255.255.255.0
ipx network 3
frame-relay interface-dlci 501
!
interface ethernet 0
ip address 140.1.15.5 255.255.255.0
ipx network 15
Example 8-19
Frame Relay Maps and Inverse ARP on Router C
RouterC#show frame-relay map
Serial0.10 (up): ip 140.1.1.1 dlci 501(0x1F5,0x7C50), dynamic,
broadcast,, status defined, active
Serial0.10 (up): ip 140.1.1.2 dlci 502(0x1F6,0x7C60), dynamic,
broadcast,, status defined, active
Serial0.10 (up): ipx 1.0200.aaaa.aaaa dlci 501(0x1F5,0x7C50), dynamic,
broadcast,, status defined, active
Serial0.10 (up): ipx 1.0200.bbbb.bbbb dlci 502(0x1F6,0x7C60), dynamic,
broadcast,, status defined, active
RouterC#debug frame-relay events
Frame Relay events debugging is on
RouterC#configure terminal
Enter configuration commands, one per line. End with Ctrl-Z.
RouterC(config)#interface serial 0.1
continues
ch08.fm Page 561 Monday, March 20, 2000 5:17 PM