哈喽，大家好！我是艺博东 ，是一个思科出身、专注于华为的网工；好了，话不多说，我们直接进入正题。
文章目录
由于特殊原因，所以把“N”字母替换为“#”符号。
如果有看不懂的地方或者是更直观的阅读，建议去我的公众号里查看。公众号：艺博东
一、拓扑
二、配置与分析
（1）AS内运行IGP，互通
（2）把AS的LSP建立起来
（3）配置AS内的MP-IBGP架构/RR
（4）ASBR之间的MP-EBGP邻居关系，互联接口启用MPLS
（5）MPLS VP#业务接入
1.底层配置
AR1
[Huawei]sysname AR1
[AR1]int g0/0/0
[AR1-GigabitEthernet0/0/0]ip address 10.1.13.1 24
[AR1-GigabitEthernet0/0/0]int l0
[AR1-LoopBack0]ip address 1.1.1.1 32
AR2
[Huawei]sysname AR2
[AR2]int g0/0/0
[AR2-GigabitEthernet0/0/0]ip address 10.1.23.2 24
[AR2-GigabitEthernet0/0/0]int l0
[AR2-LoopBack0]ip address 2.2.2.2 32
AR3
[Huawei]sysname AR3
[AR3]int g0/0/0
[AR3-GigabitEthernet0/0/0]ip address 10.1.13.3 24
[AR3-GigabitEthernet0/0/0]int g0/0/1
[AR3-GigabitEthernet0/0/1]ip address 10.1.23.3 24
[AR3-GigabitEthernet0/0/1]int g0/0/2
[AR3-GigabitEthernet0/0/2]ip address 10.1.34.3 24
[AR3-GigabitEthernet0/0/2]int l0
[AR3-LoopBack0]ip address 3.3.3.3 32
[AR3-LoopBack0]q
[AR3]rip
[AR3-rip-1]v 2
[AR3-rip-1]network 10.0.0.0
[AR3-rip-1]network 3.0.0.0
AR4
[Huawei]sysname AR4
[AR4]int g0/0/0
[AR4-GigabitEthernet0/0/0]ip address 10.1.34.4 24
[AR4-GigabitEthernet0/0/0]int g0/0/1
[AR4-GigabitEthernet0/0/1]ip address 10.1.45.4 24
[AR4-GigabitEthernet0/0/1]int l0
[AR4-LoopBack0]ip address 4.4.4.4 32
[AR4-LoopBack0]q
[AR4]rip
[AR4-rip-1]v 2
[AR4-rip-1]network 10.0.0.0
[AR4-rip-1]network 4.0.0.0
AR5
[Huawei]sysname AR5
[AR5]int g0/0/0
[AR5-GigabitEthernet0/0/0]ip address 10.1.45.5 24
[AR5-GigabitEthernet0/0/0]int g0/0/1
[AR5-GigabitEthernet0/0/1]ip address 10.1.56.5 24
[AR5-GigabitEthernet0/0/1]int l0
[AR5-LoopBack0]ip address 5.5.5.5 32
[AR5-LoopBack0]q
[AR5]rip
[AR5-rip-1]v 2
[AR5-rip-1]undo summary
[AR5-rip-1]network 10.0.0.0
[AR5-rip-1]network 5.0.0.0
[AR5-rip-1]q
[AR5]int g0/0/1
[AR5-GigabitEthernet0/0/1]undo rip output
[AR5-GigabitEthernet0/0/1]undo rip input
AR6、AR7、AR8、AR9、AR10底层配置类似
2.MPLS
AR3
[AR3]mpls lsr-id 3.3.3.3
[AR3]mpls
[AR3-mpls]mpls ldp
[AR3-mpls-ldp]int g0/0/2
[AR3-GigabitEthernet0/0/2]mpls
[AR3-GigabitEthernet0/0/2]mpls ldp
AR4
[AR4]mpls lsr-id 4.4.4.4
[AR4]mpls
[AR4-mpls]mpls ldp
[AR4-mpls-ldp]int g0/0/0
[AR4-GigabitEthernet0/0/0]mpls
[AR4-GigabitEthernet0/0/0]mpls ldp
[AR4-GigabitEthernet0/0/0]int g0/0/1
[AR4-GigabitEthernet0/0/1]mpls
[AR4-GigabitEthernet0/0/1]mpls ldp
AR5
[AR5]mpls lsr-id 5.5.5.5
[AR5]mpls
[AR5-mpls]mpls ldp
[AR5-mpls-ldp]int g0/0/0
[AR5-GigabitEthernet0/0/0]mpls
[AR5-GigabitEthernet0/0/0]mpls ldp
[AR5-GigabitEthernet0/0/0]int g0/0/1
[AR5-GigabitEthernet0/0/1]mpls
[AR5]dis mpls lsp
3.MP-IBGP
AR4（ RR）
[AR4]bgp 10
[AR4-bgp]peer 3.3.3.3 as 10
[AR4-bgp]peer 3.3.3.3 connect-interface LoopBack 0
[AR4-bgp]peer 5.5.5.5 as 10
[AR4-bgp]peer 5.5.5.5 connect-interface LoopBack 0
[AR4-bgp]ipv4-family vpnv4
[AR4-bgp-af-vpnv4]peer 3.3.3.3 enable
[AR4-bgp-af-vpnv4]peer 3.3.3.3 reflect-client
[AR4-bgp-af-vpnv4]peer 5.5.5.5 enable
[AR4-bgp-af-vpnv4]peer 5.5.5.5 reflect-client
[AR4-bgp-af-vpnv4]undo policy vpn-target
AR5
[AR5]bgp 10
[AR5-bgp]peer 4.4.4.4 as 10
[AR5-bgp]peer 4.4.4.4 connect-interface LoopBack 0
[AR5-bgp]ipv4-family vpnv4
[AR5-bgp-af-vpnv4]peer 4.4.4.4 enable
[AR4-rip-1]dis bgp peer
AR6、AR7、AR8、AR9、AR10的MP-IBGP、MPLS配置类似
4.MP-EBGP
AR5
[AR5]bgp 10
[AR5-bgp]peer 10.1.56.6 as 20
[AR5-bgp]ipv4-family vpnv4
[AR5-bgp-af-vpnv4]peer 10.1.56.6 enable
[AR5-bgp-af-vpnv4]undo policy vpn-target
AR6
[AR6]bgp 20
[AR6-bgp]peer 10.1.56.5 as-number 10
[AR6-bgp]ipv4-family vpnv4
[AR6-bgp-af-vpnv4]peer 10.1.56.5 enable
[AR6-bgp-af-vpnv4]undo policy vpn-target
[AR6]dis bgp peer
5.MPLS VP#业务接入
配置号公网，然后是公司B访问公司D；
AR3
[AR3]ip vpn-instance ybd2
[AR3-vpn-instance-ybd2]route-distinguisher 10:1
[AR3-vpn-instance-ybd2-af-ipv4]vpn-target 10:1 both
[AR3-vpn-instance-ybd2-af-ipv4]int g0/0/1
[AR3-GigabitEthernet0/0/1]ip binding vpn-instance ybd2
[AR3-GigabitEthernet0/0/1]ip address 10.1.23.3 24
[AR3-GigabitEthernet0/0/1]bgp 10
[AR3-bgp]peer 10.1.23.2 as 1
[AR3-bgp]ipv4-family vpn-instance ybd2
[AR3-bgp-ybd2]peer 10.1.23.2 as 1
[AR3-bgp-ybd2]peer 10.1.23.2 substitute-as //做AS号的伪装
AR2
[AR2]bgp 1
[AR2-bgp]peer 10.1.23.3 as 10
[AR2-bgp]network 2.2.2.2 32
[AR3-bgp]dis bgp vp#v4 all peer
[AR3]dis bgp vp#v4 all routing-table
AR8
[AR8]ip vpn-instance ybd10
[AR8-vpn-instance-ybd10]route-distinguisher 10:1
[AR8-vpn-instance-ybd10-af-ipv4]vpn-target 10:1 both
[AR8-vpn-instance-ybd10-af-ipv4]int g0/0/2
[AR8-GigabitEthernet0/0/2]ip binding vpn-instance ybd10
[AR8-GigabitEthernet0/0/2]ip address 10.1.81.8 24
[AR8-GigabitEthernet0/0/2]bgp 20
[AR8-bgp]ipv4-family vpn-instance ybd10
[AR8-bgp-ybd10]peer 10.1.81.10 as 1
[AR8-bgp-ybd10]peer 10.1.81.10 substitute-as
AR10]
[AR10]bgp 1
[AR10-bgp]peer 10.1.81.8 as 20
[AR10-bgp]network 10.10.10.10 32
[AR10]dis ip routing-table
6.MPLS VP#业务接入
公司A访问公司C；
AR3
[AR3]ip vpn-instance ybd1
[AR3-vpn-instance-ybd1]route-distinguisher 20:1
[AR3-vpn-instance-ybd1-af-ipv4]vpn-target 20:1 both
[AR3-vpn-instance-ybd1-af-ipv4]int g0/0/0
[AR3-GigabitEthernet0/0/0]ip binding vpn-instance ybd1
[AR3-GigabitEthernet0/0/0]ip address 10.1.13.3 24
[AR3-GigabitEthernet0/0/0]q
[AR3]ospf 1 vpn-instance ybd1
[AR3-ospf-1]a 0
[AR3-ospf-1-area-0.0.0.0]network 10.1.13.3 0.0.0.0
[AR3-ospf-1-area-0.0.0.0]q
[AR3-ospf-1]import-route bgp
[AR3-ospf-1]bgp 10
[AR3-bgp]ip
[AR3-bgp]ipv4-family vpn-instance ybd1
[AR3-bgp-ybd1]import-route ospf 1
AR1
[AR1]ospf 1 router-id 1.1.1.1
[AR1-ospf-1]a 0
[AR1-ospf-1-area-0.0.0.0]network 10.1.13.1 0.0.0.0
[AR1-ospf-1-area-0.0.0.0]net 1.1.1.1 0.0.0.0
AR8
[AR8]ip vpn-instance ybd9
[AR8-vpn-instance-ybd9]route-distinguisher 20:1
[AR8-vpn-instance-ybd9-af-ipv4]vpn-target 20:1 both
[AR8-vpn-instance-ybd9-af-ipv4]int g0/0/1
[AR8-GigabitEthernet0/0/1]ip binding vpn-instance ybd9
[AR8-GigabitEthernet0/0/1]ip address 10.1.89.8 24
[AR8-GigabitEthernet0/0/1]q
[AR8]isis 1 vpn-instance ybd9
[AR8-isis-1]import-route bgp
[AR8-isis-1]network-entity 12.0001.0000.0000.0008.00
[AR8-isis-1]is-level level-2
[AR8-isis-1]int g0/0/1
[AR8-GigabitEthernet0/0/1]isis enable 1
[AR8-GigabitEthernet0/0/1]bgp 20
[AR8-bgp]ipv4-family vpn-instance ybd9
[AR8-bgp-ybd9]import-route isis 1
AR9
[AR9]isis
[AR9-isis-1]network-entity 12.0001.0000.0000.0009.00
[AR9-isis-1]is-level level-2
[AR9-isis-1]int g0/0/0
[AR9-GigabitEthernet0/0/0]isis enable 1
[AR9]int l0
[AR9-LoopBack0]isis enable
[AR9]dis ip routing-table
[AR1]ping -a 1.1.1.1 9.9.9.9
公司A 1.1.1.1 访问公司C 9.9.9.9，标签是如何分配的？
封装为：
[AR1]dis ip routing-table 9.9.9.9
查看9.9.9.9路由，下一跳是10.1.13.3；
然后根据AR3的接口下绑定的实例ybd1的路由表，去查相关路由。
[AR3]dis ip routing-table vp#-instance ybd1
下一跳是5.5.5.5
[AR3]display bgp vp#v4 vpn-instance ybd1 routing-table 9.9.9.9
私网标签1031 打上标签封装成：
查看公网标签
[AR3]display mpls lsp
公网的标签是1025
打上标签封装成：
然后AR3根据G0/0/2接口发送出去
RR 查找标签
[AR4]dis mpls lsp
5.5.5.5出标签是3，然后进行弹出顶部标签，从G0/0/1接口发送出去。
AR5收到后，查看标签
收到的标签是1031的话，出标签是1031，
查看 bgp vp#v4路由表
[AR5]display bgp vp#v4 all routing-table
下一跳是10.1.56.6
[AR6]dis mpls lsp
进标签是1031，出标签是1028。
封装为
[AR6]dis bgp vp#v4 all routing-table
下一跳是8.8.8.8
[AR6]dis mpls lsp
出标签为1028，封装成：
RR 查找标签
[AR7]dis mpls lsp
8.8.8.8出标签是3，然后进行弹出顶部标签，从G0/0/1接口发送出去。
[AR8]dis mpls lsp
收到1028的标签去掉，属于ybd6的实例报文
[AR8]dis ip routing-table vp#-instance ybd9
下一跳是10.1.89.9
重启进程，抓包查看，有两层标签。
三、跨域 VP#-OptionB 的特点
公网形成一个架构，后面有公司接入进来的话，只需要在PE设备上配置。
优点： 不受ASBR之间互连链路数目的限制；ASBR不需要配置VP#实例。
缺点： VP#的路由信息是通过AS之间的ASBR来保存和扩散的，当VP#路由较多时，ASBR负担重，容易成为故障点。因此在MP-EBGP方案中，需要维护VP#路由信息的ASBR一般不在负责公网转发。
名言警句
志不真则心不热，心不热则功不紧。——颜元
欢迎访问我的易百纳技术社区文章《华为 跨域VP#-OptionB方案》
https://www.ebaina.com/articles/140000005426
好了这期就到这里了，如果你喜欢这篇文章的话，请点赞评论分享收藏，如果你还能点击关注，那真的是对我最大的鼓励。谢谢大家，下期见！