300-510 SPRI: Implementing Cisco Service Provider Advanced Routing SolutionsDemo

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QuestionQ172

MPLS and Segment Routing

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Refer to the exhibit. A network engineer needs to enable segment routing between the three autonomous systems with these requirements:

  • OSPF link-state data for area 0 routers must be sent to the controller through BGP LS.
  • EPE must be enabled on the egress node in AS 100.
  • Routers must advertise peer node SIDs to controller R1 through BGP LS.

Which configuration must the engineer apply?

  • A R2(config)# router ospf 100 -R2(config-ospf}# distribute link-state instance-id 100 throttle 10R2(config)# router bgp 100 -R2(config-bgp}# neighbor 10.10.20.1R2(config-bgp-nbr)# remote-as 300R2(config-bgp-nbr}# egress-engineeringR2(config-bgp}# neighbor 192.168.20.1R2(config-bgp-nbr}# remote-as 100R2(config-bgp-nbr}# address-family link-state link-state
  • B R1(config)# router ospf 100 -R1(config-ospf}# distribute link-state instance-id 100 throttle 10R1(config)# router bgp 100 -R1(config-bgp}# neighbor 10.10.10.1R1(config-bgp-nbr)# remote-as 200R1(config-bgp-nbr}# egress-engineeringR1(config-bgp}# neighbor 192.168.30.1R1(config-bgp-nbr}# remote-as 100R1(config-bgp-nbr}# address-family link-state link-state
  • C R2(config)# router ospf 100 -R2(config-ospf)# redistribute bgp 100R2(config)# router bgp 100 -R2(config-bgp}# neighbor 192.168.20.1R2(config-bgp-nbr)# remote-as 100R2(config-bgp-nbr}# egress-engineeringR2(config-bgp}# neighbor 10.10.10.1R2(config-bgp-nbr}# remote-as 200R2(config-bgp-nbr}# address-family link-state link-state
  • D R1(config)# router ospf 100 -R1(config-ospf)# redistribute bgp 100R1(config)# router bgp 100 -R1(config-bgp}# neighbor 192.168.30.1R1(config-bgp-nbr)# remote-as 100R1(config-bgp-nbr}# egress-engineeringR1(config-bgp}# neighbor 10.10.10.1R1(config-bgp-nbr}# remote-as 200R1(config-bgp-nbr}# address-family link-state link-state
Explanation

R2 is the AS 100 egress router because it peers externally with R4 in AS 300. Configuring egress-engineering on R2’s eBGP peer enables EPE peer-node SID advertisement. The OSPF distribute link-state command exports the OSPF link-state database to BGP-LS, and the BGP-LS address family on R2’s iBGP session to R1 carries that topology and peer information to the controller. Cisco documents distribute link-state for OSPF-to-BGP-LS export and egress-engineering on egress-node eBGP peers for SR-EPE.

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