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WAN BGP to OSPF - Single Homed Design.

elliot.sandell
Level 1
Level 1

Hello, I am currently labbing/ planning our design on how to dynamically route between our core sites into our ISP WAN (WAN only no internet).

 

We have a couple of requirements:

  • Advertise default route from each of our two core sites for external sites
  • Most external sites wont have a router onsite other than the ISP, so default route back to the ISP for most traffic.
  • Our two Core Sites have another Private P2P link that we run eBGP over.
  • Advertise either selected routes form our core sites, or all sites if we can advertise everything safely.  (No asymmetrical routing between Core sites)

We want to redistribute certain subnets from our internal OSPF areas at each core site into BGP and vice-versa, however we also want to tag the ISP to tag the default routes for each site for failover.  (Site A is primary for geographically closer sites etc).

 

Could someone help with the design here?  Not done much BGP/OSPF other than troubleshooting.

 

Design on our Cores which will connect directly into the ISP router (Via Layer 2 connections).

 

router bgp xxxx0
 no synchronization
 bgp router-id xxx.xxx.xxx
 bgp log-neighbor-changes
 network 172.xxx.xxx.xxx
 network 172.xxx.xxx.xxx mask 255.255.255.252
 redistribute ospf 100 route-map redistribute-OSPF-to-BGP
default-information originate 
 neighbor 172.xxx.xxx.xxx remote-as xxxx1


router OSPF 100
redistribute bgp 65533 route-map redistribute-BGP-to-OSPF metric-type 2

Current ASR Config.

ASR-01 & ASR-02
router bgp 65501
 bgp router-id 192.168.99.200
 bgp log-neighbor-changes
 redistribute ospf 1 route-map SNEY->YORK
 neighbor 192.168.195.249 remote-as 65502
 neighbor 192.168.195.250 remote-as 65502


router ospf 1
 router-id 192.168.99.200
 auto-cost reference-bandwidth 10000
 area 0 authentication message-digest
 timers throttle spf 10 100 5000
 timers throttle lsa 10 100 5000
 timers lsa arrival 80
 redistribute bgp 65501 metric-type 1 subnets
 passive-interface default
 no passive-interface GigabitEthernet0/0/0
 no passive-interface GigabitEthernet0/0/1
 no passive-interface Port-channel10




ASR-03 & ASR-04
router bgp 65502
 bgp router-id 192.168.6.55
 bgp log-neighbor-changes
 redistribute ospf 100 route-map SITEA->SiteB
 neighbor 192.168.195.251 remote-as 65501
 neighbor 192.168.195.252 remote-as 65501

Router ospf 100
 router-id 192.168.6.55
 redistribute static metric-type 1 subnets
 redistribute bgp 65502 metric-type 1 subnets
 passive-interface default
 no passive-interface GigabitEthernet0/0/0
 no passive-interface GigabitEthernet0/0/1
 no passive-interface Port-channel10
 network 192.168.3.0 0.0.0.3 area 699
 network 192.168.3.8 0.0.0.3 area 699
 network 192.168.6.55 0.0.0.0 area 699
 network 192.168.195.56 0.0.0.7 area 699

Cheers

 

 

 

2 Replies 2

Hello,

 

what is your specific question about your design, that is, what part is not working as per your requirements ?

Hi Sorry,

Should have made it clear, is there anything else I would need to do to achieve the above? Starting to lab it now so not fully tested as of yet.

Kind Regards

Elliot
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