Quick ppp multilink configuration:

ints bundled into the multilink dont require an IP. DOES require:

The Mu interface we create must also belong to the same Multilink Group #

R1

interface Multilink1
 ip address 172.16.0.1 255.255.255.252
 ppp multilink
 ppp multilink group 1
!
interface FastEthernet0/0
 ip address 1.1.1.1 255.255.255.0
 duplex full
!
interface Serial1/0
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
 serial restart-delay 0
!
interface Serial1/1
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
 serial restart-delay 0

R2

interface Multilink1
 ip address 172.16.0.2 255.255.255.252
 ppp multilink
 ppp multilink group 1
!
interface FastEthernet0/0
 ip address 2.2.2.1 255.255.255.0
 duplex full
!
interface Serial1/0
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
 serial restart-delay 0
!
interface Serial1/1
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
 serial restart-delay 0