华为BGP动态路由协议
文章目录
- 一：BGP概述
- 1.1 自治系统（AS）
- 12 动态路由的分类
- 2.2.1 按自治系统分为
- 1.2.2 按协议类型分类
- 1.3 BGP的概念
- 1.4 BGP的特征
- 二：BGP工作原理
- 2.1.BGP报文
- 2.1.1 Open报文
- 2.1.2UPdate报文
- 2.1.3 Notification报文
- 2.1.4 Route-Refresh
- 2.1.5 KeepAlive
- 2.2 BGP数据库
- 2.3 BGP的类型
- 三：BGP配置思路
- 四：配置实例
一：BGP概述
1.1 自治系统（AS）
1、自治系统（AS）是由一个技术管理机构管理，使用统一选路策略的一组路由器集合，
自治系统编号范围：1-65535，其中1-64511是互联网上注册公有AS号，类似公网IP地址。
64512-65535是私有AS号，类似私网IP地址
http://www.iana.org/
12 动态路由的分类
2.2.1 按自治系统分为
IGP：自治系统内部路由协议，主要：RIP1/RIP2、OSPF、ISIS、EIGRP（思科私有协议）
IGP是运行在AS内部的路由协议，主要解决AS内部的选路问题，发现、计算路由
EGP：自治系统之间的路由协议，通常：BGP
EGP是运行在AS与AS之间的路由协议，他解决AS之间选路问题。
1.2.2 按协议类型分类
距离矢量路由协议：rip1/2、BGP（路径矢量协议）、EIGRP（高级距离矢量协议）
链路状态路由协议：OSPF、ISIS ###SFP最短路径算法
1.3 BGP的概念
BGP是一种运行在AS与AS之间的动态路由协议，主要作用是在AS之间自动交换无环路由信息
以此来构建AS的拓扑图，从而消除路由环路并实施用户配置的路由策略。目前公网网络条目众多，
IGP协议无法承载，而BGP可以轻松应对，通常BGP协议用于ISP和ISP之间或跨域地域总、分公司之间
的路由信息交换
1.4 BGP的特征
●传输协议：TCP，端口号179
●BGP是外部路由协议，用来在AS之间传递路由信息
●是一种增强的路径矢量路由协议
●拥有可靠的路由更新机制
●具备丰富的Metric度量方法
●无环路协议设计
●为路由条目附带多种属性信息
●支持CIDR（无类别域间选路）
●丰富的路由过滤和路由策略
●无需周期性更新
●路由更新时只发送增量路由
●周期性发送KeepAlive报文以保持 TCP连通性
二：BGP工作原理
2.1.BGP报文
2.1.1 Open报文
OPen报文是TCP建立后发送的第一个报文，用于建立BGP对等体之间的连接关系，
主要包含BGP版本号、本地AS编号、Holdtime等信息
2.1.2UPdate报文
Update报文用来在BGP之间更新路由信息，Updata报文可以通告多条属性相同的可达路由信息
也可以撤销多条路由不可达的路由信息
2.1.3 Notification报文
报文的作用是当BGP检测到错误状态时候，立即向对等体发送NOtification报文，之后BGP就会中断
只要收到Notification报文就会返回idle状态
2.1.4 Route-Refresh
用来告知对等体所支持路由的刷新能力，BGP的入口策略路由发生变化，本地的BGP路由会向对等体发送
Route-Refresh报文，收到信息后，对等体将其路由信息重新发送给本地BGP路由器
2.1.5 KeepAlive
改报文在对等体之间周期的发送报文，用以保持连接的有效性并维护其连接，KeepAlive报文只有一个BGP
报文头，默认KeepAlive报文发送周期为60S，保持时间180S，这个类似于OSPF中的Hello报文
2.2 BGP数据库
●IP路由表：全局路由信息库，包括最优的IP路由信息
●BGP路由表：BGP路由信息库，包括本地BGPSpeak通告的路由信息，将其最优的添加到路由表中
●邻居表：对等体邻居清单表，包括对等体两端的邻居信息及邻居列表
●Adi-RIB-In:对等体宣告给本地的Speak的未处理的路由信息库
●Adjust-RIB-OUT：本地Speak宣告给指定的对等体路由信息库
2.3 BGP的类型
两种邻居：IBGP和EBGP
IBGP：同一个AS内部BGP邻居关系，IBGP邻居是指运行BGP协议的对等体两端在同一个AS域内，属于BGP AS内部
EBGP：AS之间的BGP邻居关系，EBGP通常指运行BGP协议的对等体两端在不同AS内部
三：BGP配置思路
1、启用BGP，后面跟AS系统号
2、宣告Route-id，建立邻居关系用
3、宣告和谁建立邻居关系，
4、通告BGP路由，（network、import）
四：配置实例
R1]bgp 100
[R1-bgp]router-id 1.1.1.1
[R1-bgp]peer 12.0.0.2 as-number 100
[R1-bgp]network 1.1.1.1 32
[R1] display bgp peer ####查看BGP邻居
[R1] display routing-table ####查看BGP路由表
[R1] import-route ospf 110 ###注入ospf 中的路由
1.配置接口IP地址
R1：
system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname R1
[R1]int g0/0/0
[R1-GigabitEthernet0/0/0]ip add 12.0.0.1 24
[R1-GigabitEthernet0/0/0]
Feb 7 2020 10:32:40-08:00 R1 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP
on the interface GigabitEthernet0/0/0 has entered the UP state.
[R1-GigabitEthernet0/0/0]un sh
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[R1-GigabitEthernet0/0/0]int g 0/0/1
[R1-GigabitEthernet0/0/1]ip add 15.0.0.1 30
[R1-GigabitEthernet0/0/1]
Feb 7 2020 10:33:26-08:00 R1 %%01IFNET/4/LINK_STATE(l)[1]:The line protocol IP
on the interface GigabitEthernet0/0/1 has entered the UP state.
[R1-GigabitEthernet0/0/1]un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[R1-GigabitEthernet0/0/1]int g 0/0/0
[R1-GigabitEthernet0/0/0]dis this
[V200R003C00]
#
interface GigabitEthernet0/0/0
ip address 12.0.0.1 255.255.255.0
#
return
[R1-GigabitEthernet0/0/0]un ip add 12.0.0.1 24
[R1-GigabitEthernet0/0/0]
Feb 7 2020 10:33:49-08:00 R1 %%01IFNET/4/LINK_STATE(l)[2]:The line protocol IP
on the interface GigabitEthernet0/0/0 has entered the DOWN state.
[R1-GigabitEthernet0/0/0]ip add 12.0.0.1 30
[R1-GigabitEthernet0/0/0]
Feb 7 2020 10:33:58-08:00 R1 %%01IFNET/4/LINK_STATE(l)[3]:The line protocol IP
on the interface GigabitEthernet0/0/0 has entered the UP state.
[R1-GigabitEthernet0/0/0]un sh
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[R1-GigabitEthernet0/0/0]int lo
[R1-GigabitEthernet0/0/0]int lo 0
[R1-LoopBack0]ip add 1.1.1.1 32
[R1-LoopBack0]q
[R1]dis ip int b
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 4
The number of interface that is DOWN in Physical is 0
The number of interface that is UP in Protocol is 4
The number of interface that is DOWN in Protocol is 0
Interface IP Address/Mask Physical Protocol
GigabitEthernet0/0/0 12.0.0.1/30 up up
GigabitEthernet0/0/1 15.0.0.1/30 up up
LoopBack0 1.1.1.1/32 up up(s)
NULL0 unassigned up up(s)
R2：
system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname R2
[R2]int g 0/0/0
[R2-GigabitEthernet0/0/0]ip add 12.0.0.2 30
Feb 7 2020 10:36:10-08:00 R2 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP
on the interface GigabitEthernet0/0/0 has entered the UP state.
[R2-GigabitEthernet0/0/0]un sh
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[R2-GigabitEthernet0/0/0]int g 0/0/1
[R2-GigabitEthernet0/0/1]ip add 23.0.0.1 30
Feb 7 2020 10:36:40-08:00 R2 %%01IFNET/4/LINK_STATE(l)[1]:The line protocol IP
on the interface GigabitEthernet0/0/1 has entered the UP state.
[R2-GigabitEthernet0/0/1] un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[R2-GigabitEthernet0/0/1]int lo 0
[R2-LoopBack0]ip add 2.2.2.2 32
[R2-LoopBack0]q
[R2]dis ip int b
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 4
The number of interface that is DOWN in Physical is 0
The number of interface that is UP in Protocol is 4
The number of interface that is DOWN in Protocol is 0
Interface IP Address/Mask Physical Protocol
GigabitEthernet0/0/0 12.0.0.2/30 up up
GigabitEthernet0/0/1 23.0.0.1/30 up up
LoopBack0 2.2.2.2/32 up up(s)
NULL0 unassigned up up(s)
R3：
system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname R3
[R3]int g 0/0/1
[R3-GigabitEthernet0/0/1]ip add 23.0.0.2 30
[R3-GigabitEthernet0/0/1]
Feb 7 2020 10:37:59-08:00 R3 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP
on the interface GigabitEthernet0/0/1 has entered the UP state.
[R3-GigabitEthernet0/0/1]un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[R3-GigabitEthernet0/0/1]int lo 0
[R3-LoopBack0]ip add 3.3.3.3 32
[R3-LoopBack0]q
[R3]dis ip int b
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 3
The number of interface that is DOWN in Physical is 1
The number of interface that is UP in Protocol is 3
The number of interface that is DOWN in Protocol is 1
Interface IP Address/Mask Physical Protocol
GigabitEthernet0/0/0 unassigned down down
GigabitEthernet0/0/1 23.0.0.2/30 up up
LoopBack0 3.3.3.3/32 up up(s)
NULL0 unassigned up up(s)
R5
system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname R5
[R5]int g 0/0/1
[R5-GigabitEthernet0/0/1]ip add 15.0.0.2 30
Feb 7 2020 10:39:05-08:00 R5 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP
on the interface GigabitEthernet0/0/1 has entered the UP state.
[R5-GigabitEthernet0/0/1]un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[R5-GigabitEthernet0/0/1]int lo 0
[R5-LoopBack0]ip add 5.5.5.5 32
[R5-LoopBack0]int lo 1
[R5-LoopBack1]ip add 202.0.0.1 24
[R5-LoopBack1]int lo 2
[R5-LoopBack2]ip add 202.0.1.1 24
[R5-LoopBack2]q
[R5]dis ip int b
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 5
The number of interface that is DOWN in Physical is 1
The number of interface that is UP in Protocol is 5
The number of interface that is DOWN in Protocol is 1
Interface IP Address/Mask Physical Protocol
GigabitEthernet0/0/0 unassigned down down
GigabitEthernet0/0/1 15.0.0.2/30 up up
LoopBack0 5.5.5.5/32 up up(s)
LoopBack1 202.0.0.1/24 up up(s)
LoopBack2 202.0.1.1/24 up up(s)
NULL0 unassigned up up(s)
2.开启OSPF，建立控制层面的关系
BGP 和 OSPF 之间可以共享router id
R1：
[R1]router id 1.1.1.1
Info: Router ID has been modified, please reset the relative protocols manually
to update the Router ID.
[R1]ospf 1
[R1-ospf-1]area 0
[R1-ospf-1-area-0.0.0.0]net
[R1-ospf-1-area-0.0.0.0]network 12.0.0.0 30
^
Error: Wrong parameter found at '^' position.
[R1-ospf-1-area-0.0.0.0]network 12.0.0.0 ?
IP_ADDR OSPF wild card bits
[R1-ospf-1-area-0.0.0.0]network 12.0.0.0 0.0.0.3
[R1-ospf-1-area-0.0.0.0]net
[R1-ospf-1-area-0.0.0.0]network 15.0.0.0 0.0.0.3
[R1-ospf-1-area-0.0.0.0]net
[R1-ospf-1-area-0.0.0.0]network 1.1.1.1 0.0.0.0
R2：
[R2]router id 2.2.2.2
Info: Router ID has been modified, please reset the relative protocols manually
to update the Router ID.
[R2]ospf 1
[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]netwo
[R2-ospf-1-area-0.0.0.0]network 12.0.0.0 0.0.0.3
[R2-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:47:57-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[0]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.12, NeighborE
vent=HelloReceived, NeighborPreviousState=Down, NeighborCurrentState=Init)
[R2-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:47:57-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[1]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.12, NeighborE
vent=2WayReceived, NeighborPreviousState=Init, NeighborCurrentState=2Way)
[R2-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:47:57-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[2]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.12, NeighborE
vent=AdjOk?, NeighborPreviousState=2Way, NeighborCurrentState=ExStart)
[R2-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:47:57-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[3]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.12, NeighborE
vent=NegotiationDone, NeighborPreviousState=ExStart, NeighborCurrentState=Exchan
ge)
[R2-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:47:57-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[4]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.12, NeighborE
vent=ExchangeDone, NeighborPreviousState=Exchange, NeighborCurrentState=Loading)
[R2-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:47:57-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[5]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.12, NeighborE
vent=LoadingDone, NeighborPreviousState=Loading, NeighborCurrentState=Full)
[R2-ospf-1-area-0.0.0.0]network 23.0.0.0 0.0.0.3
[R2-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0
[R2-ospf-1-area-0.0.0.0]q
[R2-ospf-1]dis ip-rout
[R2-ospf-1]dis ip-rout
^
Error: Wrong parameter found at '^' position.
[R2-ospf-1]dis ip rout
[R2-ospf-1]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 13 Routes : 13
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 OSPF 10 1 D 12.0.0.1 GigabitEthernet
0/0/0
2.2.2.2/32 Direct 0 0 D 127.0.0.1 LoopBack0
12.0.0.0/30 Direct 0 0 D 12.0.0.2 GigabitEthernet
0/0/0
12.0.0.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
12.0.0.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
15.0.0.0/30 OSPF 10 2 D 12.0.0.1 GigabitEthernet
0/0/0
23.0.0.0/30 Direct 0 0 D 23.0.0.1 GigabitEthernet
0/0/1
23.0.0.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/1
23.0.0.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/1
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
R5：
[R5]router id 5.5.5.5
Info: Router ID has been modified, please reset the relative protocols manually
to update the Router ID.
[R5]ospf 1
[R5-ospf-1]area 0
[R5-ospf-1-area-0.0.0.0]network 15.0.0.0 0.0.0.3
[R5-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:50:21-08:00 R5 %%01OSPF/4/NBR_CHANGE_E(l)[0]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.15, NeighborE
vent=HelloReceived, NeighborPreviousState=Down, NeighborCurrentState=Init)
[R5-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:50:21-08:00 R5 %%01OSPF/4/NBR_CHANGE_E(l)[1]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.15, NeighborE
vent=2WayReceived, NeighborPreviousState=Init, NeighborCurrentState=2Way)
[R5-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:50:21-08:00 R5 %%01OSPF/4/NBR_CHANGE_E(l)[2]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.15, NeighborE
vent=AdjOk?, NeighborPreviousState=2Way, NeighborCurrentState=ExStart)
[R5-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:50:21-08:00 R5 %%01OSPF/4/NBR_CHANGE_E(l)[3]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.15, NeighborE
vent=NegotiationDone, NeighborPreviousState=ExStart, NeighborCurrentState=Exchan
ge)
[R5-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:50:21-08:00 R5 %%01OSPF/4/NBR_CHANGE_E(l)[4]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.15, NeighborE
vent=ExchangeDone, NeighborPreviousState=Exchange, NeighborCurrentState=Loading)
[R5-ospf-1-area-0.0.0.0]network
Feb 7 2020 10:50:21-08:00 R5 %%01OSPF/4/NBR_CHANGE_E(l)[5]:Neighbor changes eve
nt: neighbor status changed. (ProcessId=256, NeighborAddress=1.0.0.15, NeighborE
vent=LoadingDone, NeighborPreviousState=Loading, NeighborCurrentState=Full)
[R5-ospf-1-area-0.0.0.0]network 5.5.5.5 0.0.0.0
[R5-ospf-1-area-0.0.0.0]network 202.0.0.0 0.0.0.255
[R5-ospf-1-area-0.0.0.0]network 202.0.1.0 0.0.0.255
接下来R1.R2.R5确定IBGP对等体的关系
peer 2.2.2.2 as-number 100 跟2.2.2.2 路由建立邻居关系，在AS为100的自制系统下
peer 2.2.2.2 connect-interface loo 0 使用lo 0 的接口取建立链接
R1：
[R1]bgp 100
[R1-bgp]peer 2.2.2.2 as-
[R1-bgp]peer 2.2.2.2 as-number 100
[R1-bgp]peer 2.2.2.2 co
[R1-bgp]peer 2.2.2.2 connect-interface lo
[R1-bgp]peer 2.2.2.2 connect-interface LoopBack 0
[R1-bgp]peer
[R1-bgp]peer 5.5.5.5 as-nu
[R1-bgp]peer 5.5.5.5 as-number 100
[R1-bgp]peer 5.5.5.5 con lo 0
R2：
bgp 100
peer 1.1.1.1 as-number 100
peer 1.1.1.1 connect-interface LoopBack 0
peer 5.5.5.5 as-number 100
peer 5.5.5.5 connect-interface LoopBack 0
R5：
bgp 100
peer 1.1.1.1 as-number 100
peer 1.1.1.1 connect-interface LoopBack 0
peer 2.2.2.2 as-number 100
peer 2.2.2.2 connect-interface LoopBack 0
接下来R2.R3之间建立EBGP邻居关系，不同AS的EBGP的邻居关系使用物理接口建立
peer 后面的IP地址跟的是自己的邻居
R2:
bgp 100
peer 23.0.0.2 as-number 200
peer 23.0.0.2 connect-interface g 0/0/1
R3：
首先先配置router id 3.3.3.3
bgp 200
peer 23.0.0.1 as-number 100
peer23.0.0.1 connect-interface g 0/0/1
这样他们之间的关系就建立起来了
在AS100中，把ospf的路由信息注入到BGP中
[R2]bgp 100
[R2-bgp]im
[R2-bgp]import-route ospf 1 ?
med Med for imported route
route-policy Specify a route policy
Please press ENTER to execute command
[R2-bgp]import-route ospf 1
[R2]dis bgp routing-table
BGP Local router ID is 2.2.2.2
Status codes: * - valid, > - best, d - damped,
h - history, i - internal, s - suppressed, S - Stale
Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 8
Network NextHop MED LocPrf PrefVal Path/Ogn
*> 1.1.1.1/32 0.0.0.0 1 0 ?
*> 2.2.2.2/32 0.0.0.0 0 0 ?
*> 5.5.5.5/32 0.0.0.0 2 0 ?
*> 12.0.0.0/30 0.0.0.0 0 0 ?
*> 15.0.0.0/30 0.0.0.0 2 0 ?
*> 23.0.0.0/30 0.0.0.0 0 0 ?
*> 202.0.0.1/32 0.0.0.0 2 0 ?
*> 202.0.1.1/32 0.0.0.0 2 0 ?
[R1]dis 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: 8
Network NextHop MED LocPrf PrefVal Path/Ogn
*>i 1.1.1.1/32 2.2.2.2 1 100 0 ?
i 2.2.2.2/32 2.2.2.2 0 100 0 ?
*>i 5.5.5.5/32 2.2.2.2 2 100 0 ?
*>i 12.0.0.0/30 2.2.2.2 0 100 0 ?
*>i 15.0.0.0/30 2.2.2.2 2 100 0 ?
*>i 23.0.0.0/30 2.2.2.2 0 100 0 ?
*>i 202.0.0.1/32 2.2.2.2 2 100 0 ?
*>i 202.0.1.1/32 2.2.2.2 2 100 0 ?
[R5]dis 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: 8
Network NextHop MED LocPrf PrefVal Path/Ogn
*>i 1.1.1.1/32 2.2.2.2 1 100 0 ?
i 2.2.2.2/32 2.2.2.2 0 100 0 ?
*>i 5.5.5.5/32 2.2.2.2 2 100 0 ?
*>i 12.0.0.0/30 2.2.2.2 0 100 0 ?
*>i 15.0.0.0/30 2.2.2.2 2 100 0 ?
*>i 23.0.0.0/30 2.2.2.2 0 100 0 ?
*>i 202.0.0.1/32 2.2.2.2 2 100 0 ?
*>i 202.0.1.1/32 2.2.2.2 2 100 0 ?
R3的路由表：
[R3]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 15 Routes : 15
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 EBGP 255 1 RD 23.0.0.1 GigabitEthernet
0/0/1
2.2.2.2/32 EBGP 255 0 RD 23.0.0.1 GigabitEthernet
0/0/1
3.3.3.3/32 Direct 0 0 D 127.0.0.1 LoopBack0
5.5.5.5/32 EBGP 255 2 RD 23.0.0.1 GigabitEthernet
0/0/1
12.0.0.0/30 EBGP 255 0 RD 23.0.0.1 GigabitEthernet
0/0/1
15.0.0.0/30 EBGP 255 2 RD 23.0.0.1 GigabitEthernet
0/0/1
23.0.0.0/30 Direct 0 0 D 23.0.0.2 GigabitEthernet
0/0/1
23.0.0.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/1
23.0.0.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/1
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
202.0.0.1/32 EBGP 255 2 RD 23.0.0.1 GigabitEthernet
0/0/1
202.0.1.1/32 EBGP 255 2 RD 23.0.0.1 GigabitEthernet
0/0/1
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
[R3]