In between router : Router 2

class-map OFIS_TO_MCU

match access-group 100

class-map MCU_TO_OFIS

match access-group 101

!

!

policy-map TO_MCU

class OFIS_TO_MCU

priority 1518

class class-default

fair-queue

policy-map TO_OFIS

class MCU_TO_OFIS

priority 1518

class class-default

fair-queue

!

interface Serial2/0

description Router 2 to Router 1

bandwidth 2048

ip address 206.141.24.2 255.255.255.0

no ip directed-broadcast

ip route-cache policy

no ip mroute-cache

service-policy output TO_MCU

!

interface Serial2/1

description Router 2 to Router 3

bandwidth 2048

ip address 218.141.2.1 255.255.255.0

no ip directed-broadcast

ip route-cache policy

service-policy output TO_OFIS

!

access-list 100 permit ip host 141.2.20.20 host 129.2.20.34 precedence critical

access-list 101 permit ip host 129.2.20.34 host 141.2.20.20 precedence critical