當使用BGP路徑屬性——本地優先級，進行路由優選時，優選“本地優先級”數值較大的那個。（eBGP之間更新不攜帶這個屬性）

實驗拓撲如下：

在未實現本地優先級策略前，先在各個BGP之間配置完成基本連接。

R1的基礎配如下：

hostname R1
!
interface Loopback0ip address 10.1.0.1 255.255.255.0
!
interface Loopback1ip address 10.1.1.1 255.255.255.0
!
interface Ethernet0/0ip address 100.100.12.1 255.255.255.0no shut
!
interface Ethernet0/1ip address 100.105.15.1 255.255.255.0no shut
!
router bgp 100network 10.1.0.0 mask 255.255.255.0network 10.1.1.0 mask 255.255.255.0aggregate-address 10.1.0.0 255.255.254.0 summary-onlyneighbor 100.100.12.2 remote-as 234neighbor 100.105.15.5 remote-as 500
!
end

R2的基礎配如下：

hostname R2
!
interface Ethernet0/0ip address 100.100.12.2 255.255.255.0duplex auto
!
interface Ethernet0/1ip address 10.23.88.2 255.255.255.0duplex auto
!
router bgp 234neighbor 10.23.88.3 remote-as 234neighbor 10.23.88.3 next-hop-selfneighbor 100.100.12.1 remote-as 100
!
end

R3的基礎配如下：

hostname R3
!
interface Loopback0ip address 10.3.3.3 255.255.255.255
!
interface Ethernet0/0ip address 10.23.88.3 255.255.255.0no shut
!
interface Ethernet0/1ip address 10.34.88.3 255.255.255.0no shut
!
router bgp 234network 10.3.3.3 mask 255.255.255.255neighbor IBGP peer-groupneighbor IBGP remote-as 234neighbor IBGP route-reflector-clientneighbor 10.23.88.2 peer-group IBGPneighbor 10.34.88.4 peer-group IBGP
!
end

R4的基礎配如下：

hostname R4
!
interface Ethernet0/0ip address 10.34.88.4 255.255.255.0no shut
!
interface Ethernet0/1ip address 100.200.45.4 255.255.255.0no shut
!
router bgp 234neighbor 10.34.88.3 remote-as 234neighbor 10.34.88.3 next-hop-selfneighbor 100.200.45.5 remote-as 500
!
end

R5的基礎配如下：

hostname R5
!
interface Loopback2ip address 10.1.2.5 255.255.255.0
!
interface Loopback3ip address 10.1.3.5 255.255.255.0
!
interface Ethernet0/0ip address 100.200.45.5 255.255.255.0no shut
!
interface Ethernet0/1ip address 100.105.15.5 255.255.255.0no shut
!
router bgp 500network 10.1.2.0 mask 255.255.255.0network 10.1.3.0 mask 255.255.255.0aggregate-address 10.1.2.0 255.255.254.0 summary-onlyneighbor 100.105.15.1 remote-as 100neighbor 100.200.45.4 remote-as 234
!
end

R1 ~ R5的BGP表如下：

使用本地優先級的作用在R2上應用eBGP入站策略，針對來自eBGP對等體的路由設置本地優先級設置為222；相同情況的R4針對目標網絡10.1.3.0/24的路由設置本地優先級為333。

R2新增的配置如下：

conf t
!
route-map LocPrf permit 10set local-preference 222
!
router bgp 234neighbor 100.100.12.1 route-map LocPrf in
!
end
cle ip b * so

R4新增的配置如下：

conf t
!
ip prefix-list R5L3 seq 5 permit 10.1.2.0/23
!
route-map LOCPRF permit 10match ip address prefix-list R5L3set local-preference 333
!         
route-map LOCPRF permit 20
!
router bgp 234neighbor 100.200.45.5 route-map LOCPRF in
!
end
cle ip b * so

更新策略后，在R3上驗證本地優先級和BGP路由優選路徑如下：

R3測試數據轉發路徑如下：

由此可見，BGP路徑屬性——本地優先級，主要應用在多宿主網絡環境中控制本地出站流量。

如果一條BGP路由攜帶P周知團體屬性值0xFFFFFF03，該路由只能傳遞給聯邦內部子AS的對等體；如果一條BGP路由攜帶P周知團體屬性值0xFFFFFF02，該路由不會通告給任何對等體。