Cisco CCNP and CCIE Study Notes

Consider a small network like the one below

Router1 ----[FR cloud]---- Router2

The configurations on the two routers are as below

Router1

interface Serial2
 no ip address
 encapsulation frame-relay
 no keepalive
!
interface Serial2.2 multipoint
 ip address 150.150.100.1 255.255.255.0
 frame-relay interface-dlci 102

Router2

interface Serial2
 no ip address
 encapsulation frame-relay
 no keepalive
!
interface Serial2.2 multipoint
 ip address 150.150.100.2 255.255.255.0
 frame-relay interface-dlci 201

The routers can ping each other over the frame relay interfaces. However a "show cdp neighbor" on each router shows nothing even though CDP has not been disabled in the configuration. What needs to be done to cause these two routers running IOS to see each other as CDP neigbors over the frame relay link?