BGP: LOCAL_PREF

LOCAL PREF, BGP, BGPv4, WAN, Internet, Routing, Routing-Protocol, Cisco, Networking, Layer-3

Topology

Project name: ccna-bgp15-local-pref-topology

IP

R1

enable
configure terminal
!
hostname R1
no ip domain-lookup
line console 0
exec-timeout 0 0
logging synchronous
!
interface Loopback 1
ip address 1.1.1.1 255.255.255.255
no shutdown
exit
interface GigabitEthernet 0/0
ip address 100.1.6.1 255.255.255.0
no shutdown
exit
interface GigabitEthernet 0/1
ip address 100.1.3.1 255.255.255.0
no shutdown
exit
!
end
write

R2

enable
configure terminal
!
hostname R2
no ip domain-lookup
line console 0
exec-timeout 0 0
logging synchronous
!
interface Loopback 1
ip address 2.2.2.2 255.255.255.255
no shutdown
exit
interface GigabitEthernet 0/0
ip address 100.2.4.2 255.255.255.0
no shutdown
exit
interface GigabitEthernet 0/1
ip address 100.2.6.2 255.255.255.0
no shutdown
exit
!
end
write

R3

enable
configure terminal
!
hostname R3
no ip domain-lookup
line console 0
exec-timeout 0 0
logging synchronous
!
interface Loopback 1
ip address 3.3.3.3 255.255.255.255
no shutdown
exit
interface GigabitEthernet 0/0
ip address 100.1.3.3 255.255.255.0
no shutdown
exit
interface GigabitEthernet 0/1
ip address 10.3.5.3 255.255.255.0
no shutdown
exit
interface GigabitEthernet 0/2
ip address 10.3.4.3 255.255.255.0
no shutdown
exit
!
end
write

R4

enable
configure terminal
!
hostname R4
no ip domain-lookup
line console 0
exec-timeout 0 0
logging synchronous
!
interface Loopback 1
ip address 4.4.4.4 255.255.255.255
no shutdown
exit
interface GigabitEthernet 0/0
ip address 10.4.5.4 255.255.255.0
no shutdown
exit
interface GigabitEthernet 0/1
ip address 100.2.4.4 255.255.255.0
no shutdown
exit
interface GigabitEthernet 0/2
ip address 10.3.4.4 255.255.255.0
no shutdown
exit
!
end
write

R5

enable
configure terminal
!
hostname R5
no ip domain-lookup
line console 0
exec-timeout 0 0
logging synchronous
!
interface Loopback 1
ip address 5.5.5.5 255.255.255.255
no shutdown
exit
interface Loopback 2
ip address 30.0.0.5 255.255.0.0
no shutdown
exit
interface GigabitEthernet 0/0
ip address 10.3.5.5 255.255.255.0
no shutdown
exit
interface GigabitEthernet 0/1
ip address 10.4.5.5 255.255.255.0
no shutdown
exit
!
end
write

R6

enable
configure terminal
!
hostname R6
no ip domain-lookup
line console 0
exec-timeout 0 0
logging synchronous
!
interface Loopback 1
ip address 6.6.6.6 255.255.255.255
no shutdown
exit
interface Loopback 2
ip address 50.0.0.6 255.255.0.0
no shutdown
exit
interface GigabitEthernet 0/0
ip address 100.2.6.6 255.255.255.0
no shutdown
exit
interface GigabitEthernet 0/1
ip address 100.1.6.6 255.255.255.0
no shutdown
exit
!
end
write

Static Routing

Project name: ccna-bgp15-local-pref-static

R1

configure terminal
!
ip route 3.3.3.3 255.255.255.255 100.1.3.3
ip route 6.6.6.6 255.255.255.255 100.1.6.6
!
end

R2

configure terminal
!
ip route 4.4.4.4 255.255.255.255 100.2.4.4
ip route 6.6.6.6 255.255.255.255 100.2.6.6
!
end

R3

configure terminal
!
ip route 1.1.1.1 255.255.255.255 100.1.3.1
ip route 4.4.4.4 255.255.255.255 10.3.4.4
ip route 5.5.5.5 255.255.255.255 10.3.5.5
!
end

R4

configure terminal
!
ip route 2.2.2.2 255.255.255.255 100.2.4.2
ip route 3.3.3.3 255.255.255.255 10.3.4.3
ip route 5.5.5.5 255.255.255.255 10.4.5.5
!
end

R5

configure terminal
!
ip route 3.3.3.3 255.255.255.255 10.3.5.3
ip route 4.4.4.4 255.255.255.255 10.4.5.4
!
end

R6

configure terminal
!
ip route 1.1.1.1 255.255.255.255 100.1.6.1
ip route 2.2.2.2 255.255.255.255 100.2.6.2
!
end

Verification

R1

ping 3.3.3.3 source 1.1.1.1
ping 6.6.6.6 source 1.1.1.1

R2

ping 4.4.4.4 source 2.2.2.2
ping 6.6.6.6 source 2.2.2.2

R3

ping 1.1.1.1 source 3.3.3.3
ping 4.4.4.4 source 3.3.3.3
ping 5.5.5.5 source 3.3.3.3

R4

ping 2.2.2.2 source 4.4.4.4
ping 3.3.3.3 source 4.4.4.4
ping 5.5.5.5 source 4.4.4.4

R5

ping 3.3.3.3 source 5.5.5.5
ping 4.4.4.4 source 5.5.5.5

R6

ping 1.1.1.1 source 6.6.6.6
ping 2.2.2.2 source 6.6.6.6

Base BGP Configuration

Project name: ccna-bgp15-local-pref

OSPF

R3

configure terminal
!
router ospf 1
network 10.3.5.3 0.0.0.0 area 0
network 10.3.4.3 0.0.0.0 area 0
exit
!
end

R4

configure terminal
!
router ospf 1
network 10.4.5.4 0.0.0.0 area 0
network 10.3.4.4 0.0.0.0 area 0
exit
!
end

R5

configure terminal
!
router ospf 1
network 10.3.5.5 0.0.0.0 area 0
network 10.4.5.5 0.0.0.0 area 0
exit
!
end

BGP

R1

configure terminal
!
router bgp 1
neighbor 3.3.3.3 remote-as 3
neighbor 3.3.3.3 update-source Lo1
neighbor 3.3.3.3 ebgp-multihop 2
neighbor 6.6.6.6 remote-as 50
neighbor 6.6.6.6 update-source Lo1
neighbor 6.6.6.6 ebgp-multihop 2
exit
!
end

R2

configure terminal
!
router bgp 2
neighbor 4.4.4.4 remote-as 3
neighbor 4.4.4.4 update-source Lo1
neighbor 4.4.4.4 ebgp-multihop 2
neighbor 6.6.6.6 remote-as 50
neighbor 6.6.6.6 update-source Lo1
neighbor 6.6.6.6 ebgp-multihop 2
exit
!
end

R3

configure terminal
!
router bgp 3
neighbor IBGP-POL1 peer-group
neighbor IBGP-POL1 remote-as 3
neighbor IBGP-POL1 update-source Lo1
neighbor IBGP-POL1 next-hop-self
neighbor 4.4.4.4 peer-group IBGP-POL1
neighbor 5.5.5.5 peer-group IBGP-POL1
neighbor 1.1.1.1 remote-as 1
neighbor 1.1.1.1 update-source Lo1
neighbor 1.1.1.1 ebgp-multihop 2
exit
!
end

R4

configure terminal
!
router bgp 3
neighbor IBGP-POL1 peer-group
neighbor IBGP-POL1 remote-as 3
neighbor IBGP-POL1 update-source Lo1
neighbor IBGP-POL1 next-hop-self
neighbor 3.3.3.3 peer-group IBGP-POL1
neighbor 5.5.5.5 peer-group IBGP-POL1
neighbor 2.2.2.2 remote-as 2
neighbor 2.2.2.2 update-source Lo1
neighbor 2.2.2.2 ebgp-multihop 2
exit
!
end

R5

configure terminal
!
router bgp 3
neighbor IBGP-POL1 peer-group
neighbor IBGP-POL1 remote-as 3
neighbor IBGP-POL1 update-source Lo1
neighbor IBGP-POL1 next-hop-self
neighbor 3.3.3.3 peer-group IBGP-POL1
neighbor 4.4.4.4 peer-group IBGP-POL1
network 30.0.0.0 mask 255.255.0.0
exit
!
end

R6

configure terminal
!
router bgp 50
neighbor 1.1.1.1 remote-as 1
neighbor 1.1.1.1 update-source Lo1
neighbor 1.1.1.1 ebgp-multihop 2
neighbor 2.2.2.2 remote-as 2
neighbor 2.2.2.2 update-source Lo1
neighbor 2.2.2.2 ebgp-multihop 2
network 50.0.0.0 mask 255.255.0.0
exit
!
end

Verification

R5

show ip bgp
show ip route bgp
ping 50.0.0.6 source 30.0.0.5
traceroute 50.0.0.6 source 30.0.0.5

R5#sh ip bgp
BGP table version is 3, local router ID is 30.0.0.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  30.0.0.0/16      0.0.0.0                  0         32768 i
 * i 50.0.0.0/16      4.4.4.4                  0    100      0 2 50 i
 *>i                  3.3.3.3                  0    100      0 1 50 i
R5#sh ip ro bgp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

      50.0.0.0/16 is subnetted, 1 subnets
B        50.0.0.0 [200/0] via 3.3.3.3, 03:26:42
R5#ping 50.0.0.6 source 30.0.0.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 50.0.0.6, timeout is 2 seconds:
Packet sent with a source address of 30.0.0.5 
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/10/13 ms
R5#traceroute 50.0.0.6 source 30.0.0.5
Type escape sequence to abort.
Tracing the route to 50.0.0.6
VRF info: (vrf in name/id, vrf out name/id)
  1 10.3.5.3 4 msec 9 msec 5 msec
  2 100.1.3.1 6 msec 10 msec 7 msec
  3 100.1.6.6 9 msec 8 msec 8 msec

R5#sh ip bgp
BGP table version is 5, local router ID is 30.0.0.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  30.0.0.0/16      0.0.0.0                  0         32768 i
 *>i 50.0.0.0/16      4.4.4.4                  0    200      0 2 50 i
R5#traceroute 50.0.0.6 source 30.0.0.5
Type escape sequence to abort.
Tracing the route to 50.0.0.6
VRF info: (vrf in name/id, vrf out name/id)
  1 10.4.5.4 6 msec 6 msec 9 msec
  2 100.2.4.2 7 msec 8 msec 5 msec
  3 100.2.6.6 6 msec 8 msec 6 msec
R5#traceroute 50.0.0.6 source 30.0.0.5
Type escape sequence to abort.
Tracing the route to 50.0.0.6
VRF info: (vrf in name/id, vrf out name/id)
  1 10.4.5.4 8 msec 3 msec 3 msec
  2 100.2.4.2 6 msec 6 msec 7 msec
  3 100.2.6.6 7 msec 7 msec 7 msec
R5#ping 50.0.0.6 source 30.0.0.5      
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 50.0.0.6, timeout is 2 seconds:
Packet sent with a source address of 30.0.0.5 
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 5/7/12 ms
R5#sh ip ro bgp                       
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

      50.0.0.0/16 is subnetted, 1 subnets
B        50.0.0.0 [200/0] via 4.4.4.4, 00:01:50

bgp default local-preference

R3

configure terminal
!
router bgp 3
bgp default local-preference 150
exit
!
end

R4

configure terminal
!
router bgp 3
bgp default local-preference 200
exit
!
end

Verification

R5

show ip bgp
show ip route bgp
ping 50.0.0.6 source 30.0.0.5
traceroute 50.0.0.6 source 30.0.0.5

as-path access-list

R3

configure terminal
!
ip as-path access-list 1 permit ^1_
!
route-map R-LP permit 10
match as-path 1
set local-preference 300
exit
route-map R-LP permit 20
exit
!
router bgp 3
neighbor 1.1.1.1 route-map R-LP in
exit
!
end

R4

configure terminal
!
ip as-path access-list 1 permit ^2_
!
route-map R-LP permit 10
match as-path 1
set local-preference 400
exit
route-map R-LP permit 20
exit

!
router bgp 3
neighbor 2.2.2.2 route-map R-LP in
exit
!
end

R{3,4}

clear ip bgp *

Verification

R{3,4}

show ip bgp

R5

show ip bgp
show ip route bgp
ping 50.0.0.6 source 30.0.0.5
traceroute 50.0.0.6 source 30.0.0.5

access-list

not AS_PATH ACL.

R3

configure terminal
!
access-list 1 permit 50.0.0.0 0.0.255.255
!
route-map R-LP permit 10
match ip address 1
set local-preference 500
exit
route-map R-LP permit 20
exit
!
router bgp 3
neighbor 1.1.1.1 route-map R-LP in
exit
!
end

R4

configure terminal
!
access-list 1 permit 50.0.0.0 0.0.255.255
!
route-map R-LP permit 10
match ip address 1
set local-preference 600
exit
route-map R-LP permit 20
exit

!
router bgp 3
neighbor 2.2.2.2 route-map R-LP in
exit
!
end

R{3,4}

clear ip bgp *

Verification

R{3,4}

show ip bgp

R5

show ip bgp
show ip route bgp
ping 50.0.0.6 source 30.0.0.5
traceroute 50.0.0.6 source 30.0.0.5

References

PG1X

Table of Contents

BGP: LOCAL_PREF

Topology

IP

Static Routing

Verification

Base BGP Configuration

OSPF

BGP

Verification

bgp default local-preference

Verification

as-path access-list

Verification

access-list

Verification

References

PG1X

User Tools

Site Tools

Table of Contents

BGP: LOCAL_PREF

Topology

IP

Static Routing

Verification

Base BGP Configuration

OSPF

BGP

Verification

bgp default local-preference

Verification

as-path access-list

Verification

access-list

Verification

References

Page Tools