BGP: Multihomed Customer to Single ISP in Primary-Backup Setup with Static Routes

Scenario:
Multihomed customer connected to a single service provider on multiple permanent links;
Customer network using OSPF; provider network using BGP; CE-PE via static routing;
Floating static routes configured as backup on both CE and PE;

Floating Static Routes in BGP:
Once active, the floating static routes will be permanently installed in BGP; static routes are locally sourced which is preferred;

• admin distance cannot be used in route-maps; hence, use communities
• tag floating static routes; tags mapped to specific communities;
• use route maps to modify the weight and/or local preference;
• default weight: 32768

Sample ISP Route-Community Mapping:

ISP (AS 123) Service Offerings
Advertise CU Routes	Primary?	Route Tag	Community	LocalPref
No	Yes	1000	no-export 123:31000	100
No	No	1010	no-export 123:31000	50
Yes	Yes	1001	123:31000	100
Yes	No	1011	123:31000	50

Customers Configurations:

CE1 Config (Primary link): ip route 0.0.0.0 0.0.0.0 Serial0 ! router ospf 1  default-information originate !

CE2 Config (Backup link): ip route 0.0.0.0 0.0.0.0 Serial0 250 ! router ospf 1  default-information originate !

Provider Configurations:

PE1 Config (Primary link): ip route 11.2.3.0 255.255.255.0 serial 0 tag 1000 ! router bgp 123  redistribute static route-map INTOBGP !

PE2 Config (Backup link): ip route 11.2.3.0 255.255.255.0 serial 0/0 tag 1010 250 ! router bgp 123  redistribute static route-map INTOBGP !

Common Route-Map Configurations on both PE1 and PE2:

route-map INTOBGP permit 10  match tag 1000  set community no-export 123:31000  set local-preference 100 ! route-map INTOBGP permit 20  match tag 1001  set community 123:31000  set local-preference 100 ! route-map INTOBGP permit 30  match tag 1010  set community no-export 123:31000  set local-preference 50  set weight 0 ! route-map INTOBGP permit 40  match tag 1011  set community 123:31000  set local-preference 50  set weight 0 !