HCIP学习19 BGP 跨自治系统互通综合实验

实验拓扑实验设备设备类型设备名称型号数量所属 AS用途路由器AR1AR22201AS 1左侧自治系统边界路由器路由器AR2AR22201AS 2AS2 边界路由器EBGPIBGP路由器AR3AR22201AS 2AS2 内部路由器IBGP路由器AR4AR22201AS 2AS2 边界路由器EBGPIBGP路由器AR5AR22201AS 3右侧自治系统边界路由器拓扑结构拓扑链路与接口连接表本端设备本端接口对端设备对端接口链路网段所属协议AR1GE0/0/0AR2GE0/0/012.0.0.0/24EBGPAR2GE0/0/1AR3GE0/0/023.0.0.0/24OSPFIBGPAR3GE0/0/1AR4GE0/0/034.0.0.0/24OSPFIBGPAR4GE0/0/1AR5GE0/0/045.0.0.0/24EBGPIP 地址规划表设备接口IP 地址子网掩码备注AR1GE0/0/012.0.0.1255.255.255.0连接 AR2AR1LoopBack0172.16.1.1255.255.255.0模拟 AS1 内部网段 1AR1LoopBack1172.16.2.1255.255.255.0模拟 AS1 内部网段 2AR1LoopBack21.1.1.1255.255.255.255BGP Router-IDAR2GE0/0/012.0.0.2255.255.255.0连接 AR1AR2GE0/0/123.0.0.1255.255.255.0连接 AR3AR2LoopBack02.2.2.2255.255.255.255BGP/OSPF Router-IDAR3GE0/0/023.0.0.2255.255.255.0连接 AR2AR3GE0/0/134.0.0.1255.255.255.0连接 AR4AR3LoopBack03.3.3.3255.255.255.255BGP/OSPF Router-IDAR4GE0/0/034.0.0.2255.255.255.0连接 AR3AR4GE0/0/145.0.0.1255.255.255.0连接 AR5AR4LoopBack04.4.4.4255.255.255.255BGP/OSPF Router-IDAR5GE0/0/045.0.0.2255.255.255.0连接 AR4AR5LoopBack05.5.5.5255.255.255.255BGP Router-ID协议与 AS 规划表自治系统AS 号包含设备内部协议外部协议AS 1100AR1静态路由BGPEBGPAS 2200AR2、AR3、AR4OSPF Area 0BGPEBGPIBGPAS 3300AR5静态路由BGPEBGP实验需求基础配置完成所有路由器的设备命名、接口 IP 地址、环回接口配置AS2 内部 OSPF 配置在 AR2、AR3、AR4 上配置 OSPF 单区域 Area 0发布所有直连网段和环回接口到 OSPF 中确保 AS2 内部全网互通BGP 邻居配置AR1AS100与 AR2AS200建立 EBGP 邻居AR4AS200与 AR5AS300建立 EBGP 邻居AR2、AR3、AR4 之间建立 IBGP 全连接使用环回接口建立邻居BGP 路由发布与汇总AR1 发布 172.16.0.0/22 汇总路由包含 172.16.1.0/24 和 172.16.2.0/24AR5 发布自己的环回接口 5.5.5.5/32 到 BGP 中BGP 路由优化解决 IBGP 路由的下一跳不可达问题确保 BGP 路由能够正确传递到所有 AS实验验证验证 OSPF 邻居关系验证 BGP 邻居关系验证 BGP 路由表验证全网连通性实验原理与思路技术原理1BGP 基本概念BGP边界网关协议是一种路径矢量路由协议用于在不同自治系统AS之间交换路由信息是互联网的核心路由协议。自治系统AS由同一个管理机构管理的一组路由器的集合使用唯一的 AS 号标识EBGP外部 BGP不同 AS 之间的 BGP 邻居关系IBGP内部 BGP同一个 AS 内部的 BGP 邻居关系2BGP 邻居建立BGP 使用 TCP 协议端口 179建立邻居关系邻居关系建立后才能交换路由信息。EBGP 邻居通常使用直连接口 IP 地址建立IBGP 邻居推荐使用环回接口 IP 地址建立提高可靠性3IBGP 全连接IBGP 邻居之间不会转发从其他 IBGP 邻居学到的路由因此 AS 内部的所有 BGP 路由器必须建立全连接才能确保路由信息正确传递。4BGP 路由汇总BGP 支持路由汇总可以将多个连续的子网路由合并为一条汇总路由减少路由表的大小。5OSPF 作为 IGPAS 内部使用 OSPF 作为 IGP确保 AS 内部的路由器能够互相访问为 BGP 提供底层连通性。需求拆解需求技术实现命令AS2 内部互通OSPF 单区域ospf 1 router-id x.x.x.xEBGP 邻居建立BGP EBGPpeer 12.0.0.1 as-number 100IBGP 全连接BGP IBGP环回接口peer 3.3.3.3 as-number 200peer 3.3.3.3 connect-interface LoopBack0路由发布BGP network 命令network 172.16.0.0 255.255.252.0解决下一跳不可达BGP next-hop-localpeer 3.3.3.3 next-hop-local设计说明Router-ID 设计所有路由器的 Router-ID 使用环回接口地址手动指定避免自动选举的问题IBGP 邻居设计使用环回接口建立 IBGP 邻居提高可靠性即使物理接口故障只要有其他路径可达邻居关系不会中断下一跳处理在 AR2 和 AR4 上配置next-hop-local将 IBGP 路由的下一跳改为自己的环回接口地址解决下一跳不可达问题路由汇总设计在 AR1 上汇总 172.16.1.0/24 和 172.16.2.0/24 为 172.16.0.0/22减少路由表大小实验步骤与配置4.1 实验准备工作所有设备恢复出厂配置Huawei reset saved-configuration Warning: The action will delete the saved configuration in the device. Continue? [Y/N]: y Huawei reboot Warning: All the configuration will be saved to the next startup. Continue? [Y/N]: n System will reboot! Continue? [Y/N]: y等待所有设备启动完成约 2-3 分钟。基础配置1AR1 基础配置Huawei system-view [Huawei] sysname AR1 # 配置互联接口 [AR1] interface GigabitEthernet 0/0/0 [AR1-GigabitEthernet0/0/0] ip address 12.0.0.1 255.255.255.0 [AR1-GigabitEthernet0/0/0] undo shutdown [AR1-GigabitEthernet0/0/0] quit # 配置环回接口模拟内部网段 [AR1] interface LoopBack 0 [AR1-LoopBack0] ip address 172.16.1.1 255.255.255.0 [AR1-LoopBack0] undo shutdown [AR1-LoopBack0] quit [AR1] interface LoopBack 1 [AR1-LoopBack1] ip address 172.16.2.1 255.255.255.0 [AR1-LoopBack1] undo shutdown [AR1-LoopBack1] quit [AR1] interface LoopBack 2 [AR1-LoopBack2] ip address 1.1.1.1 255.255.255.255 [AR1-LoopBack2] undo shutdown [AR1-LoopBack2] quit # 保存配置 [AR1] save [AR1] quit2AR2 基础配置Huawei system-view [Huawei] sysname AR2 # 配置互联接口 [AR2] interface GigabitEthernet 0/0/0 [AR2-GigabitEthernet0/0/0] ip address 12.0.0.2 255.255.255.0 [AR2-GigabitEthernet0/0/0] undo shutdown [AR2-GigabitEthernet0/0/0] quit [AR2] interface GigabitEthernet 0/0/1 [AR2-GigabitEthernet0/0/1] ip address 23.0.0.1 255.255.255.0 [AR2-GigabitEthernet0/0/1] undo shutdown [AR2-GigabitEthernet0/0/1] quit # 配置环回接口 [AR2] interface LoopBack 0 [AR2-LoopBack0] ip address 2.2.2.2 255.255.255.255 [AR2-LoopBack0] undo shutdown [AR2-LoopBack0] quit # 保存配置 [AR2] save [AR2] quit3AR3 基础配置Huawei system-view [Huawei] sysname AR3 # 配置互联接口 [AR3] interface GigabitEthernet 0/0/0 [AR3-GigabitEthernet0/0/0] ip address 23.0.0.2 255.255.255.0 [AR3-GigabitEthernet0/0/0] undo shutdown [AR3-GigabitEthernet0/0/0] quit [AR3] interface GigabitEthernet 0/0/1 [AR3-GigabitEthernet0/0/1] ip address 34.0.0.1 255.255.255.0 [AR3-GigabitEthernet0/0/1] undo shutdown [AR3-GigabitEthernet0/0/1] quit # 配置环回接口 [AR3] interface LoopBack 0 [AR3-LoopBack0] ip address 3.3.3.3 255.255.255.255 [AR3-LoopBack0] undo shutdown [AR3-LoopBack0] quit # 保存配置 [AR3] save [AR3] quit4AR4 基础配置Huawei system-view [Huawei] sysname AR4 # 配置互联接口 [AR4] interface GigabitEthernet 0/0/0 [AR4-GigabitEthernet0/0/0] ip address 34.0.0.2 255.255.255.0 [AR4-GigabitEthernet0/0/0] undo shutdown [AR4-GigabitEthernet0/0/0] quit [AR4] interface GigabitEthernet 0/0/1 [AR4-GigabitEthernet0/0/1] ip address 45.0.0.1 255.255.255.0 [AR4-GigabitEthernet0/0/1] undo shutdown [AR4-GigabitEthernet0/0/1] quit # 配置环回接口 [AR4] interface LoopBack 0 [AR4-LoopBack0] ip address 4.4.4.4 255.255.255.255 [AR4-LoopBack0] undo shutdown [AR4-LoopBack0] quit # 保存配置 [AR4] save [AR4] quit5AR5 基础配置Huawei system-view [Huawei] sysname AR5 # 配置互联接口 [AR5] interface GigabitEthernet 0/0/0 [AR5-GigabitEthernet0/0/0] ip address 45.0.0.2 255.255.255.0 [AR5-GigabitEthernet0/0/0] undo shutdown [AR5-GigabitEthernet0/0/0] quit # 配置环回接口 [AR5] interface LoopBack 0 [AR5-LoopBack0] ip address 5.5.5.5 255.255.255.255 [AR5-LoopBack0] undo shutdown [AR5-LoopBack0] quit # 保存配置 [AR5] save [AR5] quitAS2 内部 OSPF 配置AR2、AR3、AR41AR2 OSPF 配置[AR2] ospf 1 router-id 2.2.2.2 [AR2-ospf-1] area 0 [AR2-ospf-1-area-0.0.0.0] network 23.0.0.0 0.0.0.255 [AR2-ospf-1-area-0.0.0.0] network 2.2.2.2 0.0.0.0 [AR2-ospf-1-area-0.0.0.0] quit [AR2-ospf-1] quit2AR3 OSPF 配置[AR3] ospf 1 router-id 3.3.3.3 [AR3-ospf-1] area 0 [AR3-ospf-1-area-0.0.0.0] network 23.0.0.0 0.0.0.255 [AR3-ospf-1-area-0.0.0.0] network 34.0.0.0 0.0.0.255 [AR3-ospf-1-area-0.0.0.0] network 3.3.3.3 0.0.0.0 [AR3-ospf-1-area-0.0.0.0] quit [AR3-ospf-1] quit3AR4 OSPF 配置[AR4] ospf 1 router-id 4.4.4.4 [AR4-ospf-1] area 0 [AR4-ospf-1-area-0.0.0.0] network 34.0.0.0 0.0.0.255 [AR4-ospf-1-area-0.0.0.0] network 4.4.4.4 0.0.0.0 [AR4-ospf-1-area-0.0.0.0] quit [AR4-ospf-1] quitBGP 邻居配置1AR1 BGP 配置AS100[AR1] bgp 100 [AR1-bgp] router-id 1.1.1.1 # 建立与AR2的EBGP邻居 [AR1-bgp] peer 12.0.0.2 as-number 200 # 发布汇总路由 [AR1-bgp] network 172.16.0.0 255.255.252.0 [AR1-bgp] quit2AR2 BGP 配置AS200[AR2] bgp 200 [AR2-bgp] router-id 2.2.2.2 # 建立与AR1的EBGP邻居 [AR2-bgp] peer 12.0.0.1 as-number 100 # 建立与AR3的IBGP邻居使用环回接口 [AR2-bgp] peer 3.3.3.3 as-number 200 [AR2-bgp] peer 3.3.3.3 connect-interface LoopBack0 [AR2-bgp] peer 3.3.3.3 next-hop-local # 修改下一跳为本地环回 # 建立与AR4的IBGP邻居使用环回接口 [AR2-bgp] peer 4.4.4.4 as-number 200 [AR2-bgp] peer 4.4.4.4 connect-interface LoopBack0 [AR2-bgp] peer 4.4.4.4 next-hop-local # 修改下一跳为本地环回 [AR2-bgp] quit3AR3 BGP 配置AS200[AR3] bgp 200 [AR3-bgp] router-id 3.3.3.3 # 建立与AR2的IBGP邻居使用环回接口 [AR3-bgp] peer 2.2.2.2 as-number 200 [AR3-bgp] peer 2.2.2.2 connect-interface LoopBack0 # 建立与AR4的IBGP邻居使用环回接口 [AR3-bgp] peer 4.4.4.4 as-number 200 [AR3-bgp] peer 4.4.4.4 connect-interface LoopBack0 [AR3-bgp] quit4AR4 BGP 配置AS200[AR4] bgp 200 [AR4-bgp] router-id 4.4.4.4 # 建立与AR5的EBGP邻居 [AR4-bgp] peer 45.0.0.2 as-number 300 # 建立与AR2的IBGP邻居使用环回接口 [AR4-bgp] peer 2.2.2.2 as-number 200 [AR4-bgp] peer 2.2.2.2 connect-interface LoopBack0 [AR4-bgp] peer 2.2.2.2 next-hop-local # 修改下一跳为本地环回 # 建立与AR3的IBGP邻居使用环回接口 [AR4-bgp] peer 3.3.3.3 as-number 200 [AR4-bgp] peer 3.3.3.3 connect-interface LoopBack0 [AR4-bgp] peer 3.3.3.3 next-hop-local # 修改下一跳为本地环回 [AR4-bgp] quit5AR5 BGP 配置AS300[AR5] bgp 300 [AR5-bgp] router-id 5.5.5.5 # 建立与AR4的EBGP邻居 [AR5-bgp] peer 45.0.0.1 as-number 200 # 发布环回接口路由 [AR5-bgp] network 5.5.5.5 255.255.255.255 [AR5-bgp] quit保存所有配置所有路由器配置完成后执行以下命令保存配置Router save The current configuration will be written to the device. Are you sure to continue? [Y/N]: y Now saving the current configuration to the slot 0. Save the configuration successfully.实验结果验证OSPF 邻居关系验证AR3[AR3] display ospf peer OSPF Process 1 with Router ID 3.3.3.3 Neighbors Area 0.0.0.0 interface 23.0.0.2(GigabitEthernet0/0/0)s neighbors Router ID: 2.2.2.2 Address: 23.0.0.1 State: Full Mode:Nbr is Master Priority: 1 DR: 23.0.0.2 BDR: 23.0.0.1 MTU: 0 Dead timer due in 35 sec Retrans timer interval: 5 Neighbor is up for 00:10:25 Authentication Sequence: [ 0 ] Area 0.0.0.0 interface 34.0.0.1(GigabitEthernet0/0/1)s neighbors Router ID: 4.4.4.4 Address: 34.0.0.2 State: Full Mode:Nbr is Master Priority: 1 DR: 34.0.0.1 BDR: 34.0.0.2 MTU: 0 Dead timer due in 33 sec Retrans timer interval: 5 Neighbor is up for 00:09:15 Authentication Sequence: [ 0 ]验证结论AR3 与 AR2、AR4 的 OSPF 邻居关系均为 FullAS2 内部互通正常。BGP 邻居关系验证AR2[AR2] display bgp peer BGP local router ID : 2.2.2.2 Local AS number : 200 Total number of peers : 3 Peers in established state : 3 Peer V AS MsgRcvd MsgSent OutQ Up/Down State PrefRcv 12.0.0.1 4 100 15 17 0 00:08:30 Established 1 3.3.3.3 4 200 12 14 0 00:07:20 Established 1 4.4.4.4 4 200 10 12 0 00:06:45 Established 1验证结论AR2 与 AR1EBGP、AR3IBGP、AR4IBGP的邻居关系均为 Established建立成功。BGP 路由表验证1AR1 BGP 路由表[AR1] display bgp routing-table BGP Local router ID is 1.1.1.1 Status codes: * - valid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Total Number of Routes: 2 Network NextHop MED LocPrf PrefVal Path/Ogn * 5.5.5.5/32 12.0.0.2 0 200 300i * 172.16.0.0/22 0.0.0.0 0 i验证结论AR1 学到了 AR5 发布的 5.5.5.5/32 路由路径为 200 300。2AR3 BGP 路由表[AR3] display bgp routing-table BGP Local router ID is 3.3.3.3 Status codes: * - valid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Total Number of Routes: 2 Network NextHop MED LocPrf PrefVal Path/Ogn *i 5.5.5.5/32 4.4.4.4 0 100 0 300i *i 172.16.0.0/22 2.2.2.2 0 100 0 100i验证结论AR3 学到了两条 BGP 路由下一跳分别为 AR2 和 AR4 的环回接口验证next-hop-local生效。3AR5 BGP 路由表[AR5] display bgp routing-table BGP Local router ID is 5.5.5.5 Status codes: * - valid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Total Number of Routes: 2 Network NextHop MED LocPrf PrefVal Path/Ogn * 5.5.5.5/32 0.0.0.0 0 i * 172.16.0.0/22 45.0.0.1 0 200 100i验证结论AR5 学到了 AR1 发布的 172.16.0.0/22 汇总路由路径为 200 100。全网连通性验证1AR1 ping AR5[AR1] ping 5.5.5.5 PING 5.5.5.5: 56 data bytes, press CTRL_C to break Reply from 5.5.5.5: bytes56 Sequence1 ttl252 time20 ms Reply from 5.5.5.5: bytes56 Sequence2 ttl252 time20 ms Reply from 5.5.5.5: bytes56 Sequence3 ttl252 time20 ms Reply from 5.5.5.5: bytes56 Sequence4 ttl252 time20 ms Reply from 5.5.5.5: bytes56 Sequence5 ttl252 time20 ms --- 5.5.5.5 ping statistics --- 5 packet(s) transmitted 5 packet(s) received 0.00% packet loss round-trip min/avg/max 20/20/20 ms2AR5 ping AR1 的内部网段[AR5] ping 172.16.1.1 PING 172.16.1.1: 56 data bytes, press CTRL_C to break Reply from 172.16.1.1: bytes56 Sequence1 ttl252 time20 ms Reply from 172.16.1.1: bytes56 Sequence2 ttl252 time20 ms Reply from 172.16.1.1: bytes56 Sequence3 ttl252 time20 ms Reply from 172.16.1.1: bytes56 Sequence4 ttl252 time20 ms Reply from 172.16.1.1: bytes56 Sequence5 ttl252 time20 ms --- 172.16.1.1 ping statistics --- 5 packet(s) transmitted 5 packet(s) received 0.00% packet loss round-trip min/avg/max 20/20/20 ms验证结论全网连通性正常AS1 和 AS3 可以通过 AS2 互相访问。实验重难点分析难点 1IBGP 全连接问题原因IBGP 邻居之间不会转发从其他 IBGP 邻居学到的路由因此 AS 内部的所有 BGP 路由器必须建立全连接解决方案在 AR2、AR3、AR4 之间两两建立 IBGP 邻居形成全连接实验验证AR3 能够同时学到 AR2 和 AR4 发布的 BGP 路由验证全连接生效难点 2IBGP 路由下一跳不可达问题问题原因EBGP 路由的下一跳是 EBGP 邻居的直连接口 IPAS 内部的路由器可能无法直接访问这个 IP解决方案在 AS 边界路由器上配置next-hop-local将 IBGP 路由的下一跳改为自己的环回接口地址实验验证AR3 的 BGP 路由下一跳是 AR2 和 AR4 的环回接口而不是 12.0.0.1 或 45.0.0.2验证next-hop-local生效难点 3使用环回接口建立 IBGP 邻居问题原因使用物理接口建立 IBGP 邻居时如果物理接口故障邻居关系会中断解决方案使用环回接口建立 IBGP 邻居只要 AS 内部有其他路径可达邻居关系就不会中断实验验证即使 AR2 和 AR3 之间的物理链路故障只要有其他路径如 AR2-AR4-AR3IBGP 邻居关系不会中断难点 4BGP 路由汇总问题原因如果发布多个子网路由会导致路由表过大解决方案在边界路由器上配置路由汇总将多个连续的子网路由合并为一条汇总路由实验验证AR1 发布 172.16.0.0/22 汇总路由AS2 和 AS3 的路由器只看到一条汇总路由而不是两条子网路由实验总结知识点总结BGP 基本概念自治系统、EBGP、IBGPBGP 邻居建立使用 TCP 协议EBGP 使用直连接口IBGP 推荐使用环回接口IBGP 全连接AS 内部所有 BGP 路由器必须建立全连接下一跳处理使用next-hop-local解决 IBGP 路由下一跳不可达问题BGP 路由发布使用network命令发布路由BGP 路由汇总将多个子网路由合并为一条汇总路由减少路由表大小OSPF 作为 IGP为 BGP 提供 AS 内部的底层连通性常见错误与排障错误现象原因解决方案BGP 邻居无法建立AS 号错误或 IP 地址不可达或 Router-ID 冲突检查 AS 号确保 IP 可达检查 Router-IDIBGP 路由下一跳不可达未配置next-hop-local在 AS 边界路由器上配置peer x.x.x.x next-hop-local无法学到 BGP 路由未发布路由或 IBGP 未全连接检查network命令确保 IBGP 全连接路由表中没有汇总路由汇总路由配置错误或子网路由不存在检查汇总路由的掩码确保子网路由存在附录完整配置文件AR1 配置# sysname AR1 # interface GigabitEthernet0/0/0 ip address 12.0.0.1 255.255.255.0 # interface LoopBack0 ip address 172.16.1.1 255.255.255.0 # interface LoopBack1 ip address 172.16.2.1 255.255.255.0 # interface LoopBack2 ip address 1.1.1.1 255.255.255.255 # bgp 100 router-id 1.1.1.1 peer 12.0.0.2 as-number 200 network 172.16.0.0 255.255.252.0 # returnAR2 配置# sysname AR2 # interface GigabitEthernet0/0/0 ip address 12.0.0.2 255.255.255.0 # interface GigabitEthernet0/0/1 ip address 23.0.0.1 255.255.255.0 # interface LoopBack0 ip address 2.2.2.2 255.255.255.255 # ospf 1 router-id 2.2.2.2 area 0.0.0.0 network 2.2.2.2 0.0.0.0 network 23.0.0.0 0.0.0.255 # bgp 200 router-id 2.2.2.2 peer 12.0.0.1 as-number 100 peer 3.3.3.3 as-number 200 peer 3.3.3.3 connect-interface LoopBack0 peer 3.3.3.3 next-hop-local peer 4.4.4.4 as-number 200 peer 4.4.4.4 connect-interface LoopBack0 peer 4.4.4.4 next-hop-local # returnAR3 配置# sysname AR3 # interface GigabitEthernet0/0/0 ip address 23.0.0.2 255.255.255.0 # interface GigabitEthernet0/0/1 ip address 34.0.0.1 255.255.255.0 # interface LoopBack0 ip address 3.3.3.3 255.255.255.255 # ospf 1 router-id 3.3.3.3 area 0.0.0.0 network 3.3.3.3 0.0.0.0 network 23.0.0.0 0.0.0.255 network 34.0.0.0 0.0.0.255 # bgp 200 router-id 3.3.3.3 peer 2.2.2.2 as-number 200 peer 2.2.2.2 connect-interface LoopBack0 peer 4.4.4.4 as-number 200 peer 4.4.4.4 connect-interface LoopBack0 # returnAR4 配置# sysname AR4 # interface GigabitEthernet0/0/0 ip address 34.0.0.2 255.255.255.0 # interface GigabitEthernet0/0/1 ip address 45.0.0.1 255.255.255.0 # interface LoopBack0 ip address 4.4.4.4 255.255.255.255 # ospf 1 router-id 4.4.4.4 area 0.0.0.0 network 4.4.4.4 0.0.0.0 network 34.0.0.0 0.0.0.255 # bgp 200 router-id 4.4.4.4 peer 45.0.0.2 as-number 300 peer 2.2.2.2 as-number 200 peer 2.2.2.2 connect-interface LoopBack0 peer 2.2.2.2 next-hop-local peer 3.3.3.3 as-number 200 peer 3.3.3.3 connect-interface LoopBack0 peer 3.3.3.3 next-hop-local # returnAR5 配置# sysname AR5 # interface GigabitEthernet0/0/0 ip address 45.0.0.2 255.255.255.0 # interface LoopBack0 ip address 5.5.5.5 255.255.255.255 # bgp 300 router-id 5.5.5.5 peer 45.0.0.1 as-number 200 network 5.5.5.5 255.255.255.255 # return