Inter-Provider MPLS Solutions之option B(2)

Inter-Provider MPLS Solutions之option B--（MP-eBGP between RRs）

MP-eBGP between RRs for *** routes

-- RR（Route Reflector）-路由反射器也能夠被用於***v4。在AS之間的***環境下，路由反射器已經在爲AS維護全部的***v4信息了。所以，邏輯上應該直接在RR之間交換AS間的***信息，而不給ASBR添加負擔。這樣減小了ASBR上的資源使用。
在每個AS中，PE只與本AS內的RR創建對等體關係並經過多協議iBGP交換***v4前綴。兩臺RR 經過多跳多協議eBGP交換***v4信息。
兩臺ASBR只交換IPv4信息，而不是***v4信息。
-- 值得注意的是，任何BGP下一跳的改變將重置標籤棧。要在兩臺PE設備之間創建端到端的LSP，必需要使用遠端PE的BGP下一跳在穿越AS邊界時不被改變。若是在RR上重置了BGP下一跳，新的標籤棧就不得不被建立。解決此問題的辦法就是使用命令「neighbor
next-hop-unchanged」來搞定。
-- 要讓兩臺RR創建BGP會話，它們之間必須存在IPv4的可達性。在各自的AS中，PE與ASBR之間和RR之間已經存在了一條IGP LSP了。所以須要在兩個自制系統間鏈接這兩條LSP。
-- IPv4的eBGP已經在兩個自制系統之間運行了，因此一個明顯的解決辦法就是讓BGP爲IPv4前綴運載標籤。BGP多協議能力提供了爲IPv4前綴運載標籤的一個選項。要發送標籤，能夠在IPv4地址簇下配置BGP命令「neighbor send-label」。
-- 讓端到端的LSP運載***流量，必需要使遠端RR和PE的環回地址攜帶正確的標籤，並能被本地RR和PE抵達。
● ASBR把存在於eBGP中的RR和PE的環回地址重分發進本地AS的IGP中。這種方法易於實現，但若是被分發的地址衆多其不穩定，也行就不合適了。

● ASBR在IPv4 iBGP中給遠端RR和遠端PE的環回地址分配標籤，並把他們通告給本地RR和本地PE。這種方法把來自於另外一個AS的地址和本地IGP隔離開來。因爲涉及更多的標籤，所以這種方法更復雜。

保持標籤的一致性（LSP中途不改變標籤）

實驗拓撲

需求
1）網段以及IP地址如拓撲所示
2）各AS中執行的協議如拓撲所示
3）配置RR設備完成***

配置
**Y-PE1
！
hostname Y-PE1
!
mpls label range 100 199
mpls ldp router-id Loopback0 force
!
ip vrf A
rd 100:7
route-target export 1007:2008
route-target import 2008:1007
!
interface Loopback0
ip address 1.1.1.1 255.255.255.255
!
interface Ethernet0/0
ip address 10.0.12.1 255.255.255.0
mpls ip
!
interface Ethernet0/1
ip vrf forwarding A
ip address 17.1.1.1 255.255.255.0
!
router ospf 110
router-id 1.1.1.1
network 1.1.1.1 0.0.0.0 area 0
network 10.0.12.0 0.0.0.255 area 0
!
router rip
!
address-family ipv4 vrf A
redistribute bgp 100 metric transparent
network 17.0.0.0
no auto-summary
version 2
exit-address-family
!
router bgp 100
bgp router-id 1.1.1.1
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 2.2.2.2 remote-as 100
neighbor 2.2.2.2 update-source Loopback0
!
address-family ipv4
network 1.1.1.1 mask 255.255.255.255 ---在BGP的ipv4地址簇中通告1.1.1.1/32（方便壓標籤--路由的下一跳）
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 send-label ---AS100內，iBGP鄰居間發送標籤（默認不發）
exit-address-family
!
address-family ***v4 ---和RR創建***v4鄰居
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 send-community extended
exit-address-family
!
address-family ipv4 vrf A
redistribute rip
exit-address-family
！

**Y-RR1
！
hostname Y-RR1
!
mpls ldp
router-id 2.2.2.2
interface GigabitEthernet0/0/0/0
!
interface GigabitEthernet0/0/0/1
!
!
mpls label range table 0 16200 16299
！
interface Loopback0
ipv4 address 2.2.2.2 255.255.255.255
!
interface GigabitEthernet0/0/0/0
ipv4 address 10.0.12.2 255.255.255.0
!
interface GigabitEthernet0/0/0/1
ipv4 address 10.0.23.2 255.255.255.0
!
route-policy eBGP
pass
end-policy
!
router ospf 110
router-id 2.2.2.2
address-family ipv4 unicast
area 0
interface Loopback0
!
interface GigabitEthernet0/0/0/0
!
interface GigabitEthernet0/0/0/1
!
!
!
router bgp 100
bgp router-id 2.2.2.2
address-family ipv4 unicast
network 2.2.2.2/32 ---通告2.2.2.2/32路由（方便和G-RR之間5.5.5.5/32創建eBGP的***v4鄰居）
!
address-family ***v4 unicast
!
neighbor 1.1.1.1
remote-as 100
update-source Loopback0
address-family ipv4 labeled-unicast --BGP鄰居間分發標籤
route-reflector-client
!
address-family ***v4 unicast
route-reflector-client
!
!
neighbor 3.3.3.3
remote-as 100
update-source Loopback0
address-family ipv4 labeled-unicast
route-reflector-client
!
!
neighbor 5.5.5.5 ---和G-RR創建eBGP的***v4鄰居
remote-as 200
ebgp-multihop 255
update-source Loopback0
address-family ***v4 unicast
route-policy eBGP in
route-policy eBGP out
next-hop-unchanged ---標籤的分發過程當中不改變標籤
!
!
!

**Y-ASBR1
！
hostname Y-ASBR1
!
mpls label range 300 399
mpls ldp router-id Loopback0 force
！
interface Loopback0
ip address 3.3.3.3 255.255.255.255
！
interface Ethernet0/0 ****Link-to-G-ASBR1
ip address 10.0.34.3 255.255.255.0
mpls bgp forwarding ---分發傳遞BGP的標籤
！
interface Ethernet0/1
ip address 10.0.23.3 255.255.255.0
mpls ip
！
router ospf 110
router-id 3.3.3.3
network 3.3.3.3 0.0.0.0 area 0
network 10.0.23.0 0.0.0.255 area 0
!
router bgp 100
bgp router-id 3.3.3.3
bgp log-neighbor-changes
no bgp default ipv4-unicast
no bgp default route-target filter
neighbor 2.2.2.2 remote-as 100
neighbor 2.2.2.2 update-source Loopback0
neighbor 10.0.34.4 remote-as 200
!
address-family ipv4
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 next-hop-self
neighbor 2.2.2.2 send-label --向iBGP鄰居發送標籤
neighbor 10.0.34.4 activate
neighbor 10.0.34.4 send-label --向eBGP對等體分發標籤
exit-address-family
！

**G-ASBR1
！
hostname G-ASBR1
!
mpls label range 400 499
mpls ldp router-id Loopback0 force
！
interface Loopback0
ip address 4.4.4.4 255.255.255.255
！
interface Ethernet0/0 ***Link-to-Y-ASBR1
ip address 10.0.34.4 255.255.255.0
mpls bgp forwarding
！
interface Ethernet0/1
ip address 10.0.45.4 255.255.255.0
mpls ip
！
router ospf 110
router-id 4.4.4.4
network 4.4.4.4 0.0.0.0 area 0
network 10.0.45.0 0.0.0.255 area 0
!
router bgp 200
bgp router-id 4.4.4.4
bgp log-neighbor-changes
no bgp default ipv4-unicast
no bgp default route-target filter
neighbor 5.5.5.5 remote-as 200
neighbor 5.5.5.5 update-source Loopback0
neighbor 10.0.34.3 remote-as 100
!
address-family ipv4
neighbor 5.5.5.5 activate
neighbor 5.5.5.5 next-hop-self
neighbor 5.5.5.5 send-label --向iBGP鄰居分發標籤
neighbor 10.0.34.3 activate
neighbor 10.0.34.3 send-label --向eBGP對等體分發標籤
exit-address-family
！

**G-RR1
！
hostname G-RR1
!
mpls ldp
router-id 5.5.5.5
interface GigabitEthernet0/0/0/0
!
interface GigabitEthernet0/0/0/1
!
!
interface Loopback0
ipv4 address 5.5.5.5 255.255.255.255
!
interface GigabitEthernet0/0/0/0
ipv4 address 10.0.45.5 255.255.255.0
!
interface GigabitEthernet0/0/0/1
ipv4 address 10.0.56.5 255.255.255.0
!
route-policy eBGP
pass
end-policy
!
router ospf 110
router-id 5.5.5.5
address-family ipv4 unicast
area 0
interface Loopback0
!
interface GigabitEthernet0/0/0/0
!
interface GigabitEthernet0/0/0/1
!
!
!
router bgp 200
bgp router-id 5.5.5.5
address-family ipv4 unicast
network 5.5.5.5/32 --在BGP中通告路由（和2.2.2.2/32創建eBGP的***v4鄰居）
!
address-family ***v4 unicast
!
neighbor 2.2.2.2
remote-as 100
ebgp-multihop 255
update-source Loopback0
address-family ***v4 unicast
route-policy eBGP in
route-policy eBGP out
next-hop-unchanged --標籤傳遞過程當中不改變標籤
!
!
neighbor 4.4.4.4
remote-as 200
update-source Loopback0
address-family ipv4 labeled-unicast --向iBGP鄰居分發標籤
route-reflector-client
!
!
neighbor 6.6.6.6
remote-as 200
update-source Loopback0
address-family ipv4 labeled-unicast
route-reflector-client
!
address-family ***v4 unicast
route-reflector-client
!
!
!

**G-PE1
！
hostname G-PE1
!
mpls label range 600 699
mpls ldp router-id Loopback0 force
！
ip vrf B
rd 200:8
route-target export 2008:1007
route-target import 1007:2008
！
interface Loopback0
ip address 6.6.6.6 255.255.255.255
！
interface Ethernet0/0
ip address 10.0.56.6 255.255.255.0
mpls ip
！
interface Ethernet0/1
ip vrf forwarding B
ip address 68.1.1.6 255.255.255.0
！
router ospf 110
router-id 6.6.6.6
network 6.6.6.6 0.0.0.0 area 0
network 10.0.56.0 0.0.0.255 area 0
！
router rip
!
address-family ipv4 vrf B
redistribute bgp 200 metric transparent
network 68.0.0.0
no auto-summary
version 2
exit-address-family
！
router bgp 200
bgp router-id 6.6.6.6
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 5.5.5.5 remote-as 200
neighbor 5.5.5.5 update-source Loopback0
!
address-family ipv4
network 6.6.6.6 mask 255.255.255.255 --在BGP中通告路由（方便壓標籤）
neighbor 5.5.5.5 activate
neighbor 5.5.5.5 send-label
exit-address-family
!
address-family ***v4
neighbor 5.5.5.5 activate
neighbor 5.5.5.5 send-community extended
exit-address-family
!
address-family ipv4 vrf B
redistribute rip
exit-address-family
！

**CE1
！
hostname CE1
!
interface Loopback0
ip address 7.7.7.7 255.255.255.255
！
interface Ethernet0/1
ip address 17.1.1.7 255.255.255.0
！
router rip
version 2
network 7.0.0.0
network 17.0.0.0
no auto-summary
！

**CE2
！
hostname CE2
!
interface Loopback0
ip address 8.8.8.8 255.255.255.255
！
interface Ethernet0/1
ip address 68.1.1.8 255.255.255.0
！
router rip
version 2
network 8.0.0.0
network 68.0.0.0
no auto-summary
！