Aug 26, 2008

Implementing the DiffServ Tunneling Models in Cisco IOS - Uniform Model

MPLS DiffServ Uniform Model
  • Ingree PE


!!! Ingress interface:
!
class-map IP_TOS
match ip precedence 4
!
policy-map SET_MPLS_PHB
class IP_TOS4
police cir 8000
conform-action set-mpls-exp-transmit 4
exceed-action set-mpls-exp-transmit 2
!
interface ethernet 0/0
service-policy input SET_MPLS_PHB
!
!
!
!!! Egree interface:
!
class-map MPLS_EXP
match mpls experimental topmost 2 4
!
policy-map SET_QOS_OUT
class MPLS_EXP
bandwidth percent 40
random-detect
!
interface ethernet 1/0
service-policy output SET_QOS_OUT


For the Uniform model, you must copy the precedence bits to the EXP bits on the ingress PE.



  • P Router


!!! Ingree interface:
!
! Nothing needed because the EXP bits are copied to the swapped outgoing label by default.
!
!!! Egress interface:
!
class-map MPLS_EXP
match mpls experimental topmost 2 4
!
policy-map SET_QOS_OUT
class MPLS_EXP
bandwidth percent 40
random-detect
!
interface ethernet 0/0
service-policy output SET_QOS_OUT




  • PHP P Router


!!! Ingress interface:
!
class-map MPLS_EXP
match mpls experimental topmost 2 4
!
policy-map EXP_IN_QOS_GROUP
class MPLS_EXP
set qos-group mpls experimental topmost
!
interface ethernet 0/0
service-policy input EXP_IN_QOS_GROUP
!
!
!
!!! Egress interface:
!
class-map QOS_GROUP
match qos-group 2
match qos-group 4
!
policy-map QOS_GROUP_OUT_EXP
class QOS_GROUP
set mpls experimental topmost qos-group
bandwidth percent 40
random-detect
!
interface ethernet 1/0
service-policy output QOS_GROUP_OUT_EXP


On the PHP router, qos-group ensures that the EXP bit values 2 and 4 are copied to the exposed outgoing top label after popping the incoming label.



  • Egress PE


!!! Ingress interface:
!
class-map MPLS_EXP
match mpls experimental topmost 2 4
!
policy-map EXP_IN_QOS_GROUP
class MPLS_EXP
set qos-group mpls experimental topmost
!
interface ethernet 0/0
service-policy input EXP_IN_QOS_GROUP
!
!
!
!!! Egress interface:
!
class-map QOS_GROUP
match qos-group 2
match qos-group 4
!
policy-map SET_TOS_OUT
class QOS_GROUP
set precedecnce qos-group
bandwidth percent 40
random-detect
!
interface ethernet 3/1
service-policy output SET_TOS_OUT


On the egress PE, copy the EXP bits to the precedence bits by using qos-group.

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