Inter-AS MPLT Option B RT Translation

In this example an ASBR translates the private WAN route-target 65001:100 to the RT used on the service provider core which is a unique/public RT (100:330) because the private RT used inside the customer WAN is used on other customer WANs connected to the service provider core (overlapping RTs):

! Config is from the perspective of the service provider core ASBR.

! Change the inbound RT filter to translate 65001:100 to 100:330:

route-policy CUST1-PE-RT-Filter-IN
  if extcommunity rt matches-any (65001:100) then
    set extcommunity rt (100:330)
    pass
  endif
  if extcommunity rt matches-any CUST1-OptB-RT-Filter-IN then ! All other permited RTs
    pass
  endif
end-policy


! Change the outbound RT filter to translate 100:330 back to 65001:100:

route-policy CUST1-PE-RT-Filter-OUT
  if extcommunity rt matches-any (100:330) then
    set extcommunity rt (65001:100)
    pass
  endif
  if extcommunity rt matches-any CUST1-OptB-RT-Filter-OUT then
    pass
  endif
end-policy

The following example is from the perspective on the customer WAN ASBR, and is IOS syntax:

ip extcommunity-list standard CUST1-VRF10-PRIVATE permit rt 65001:100
ip extcommunity-list standard CUST1-VRF10-PUBLIC  permit rt 100:330

route-map ASBR-IN-VPNV4 permit 10
 match extcommunity CUST1-VRF10-PUBLIC
 set extcommunity rt 65001:100
route-map ASBR-IN-VPNV4 permit 20
 match extcommunity 1  ! All other permited RTs
 exit

route-map ASBR-OUT-VPNV4 permit 10
 match extcommunity CUST1-VRF10-PRIVATE
 set extcommunity rt 100:330
route-map ASBR-OUT-VPNV4 permit 20
 match extcommunity 1
 exit

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