边界网关协议BGP实践课(7)—AS_Path属性

概述

学习边界网关协议BGP的关键在于如何理解和应用协议的“属性”，因此，本期文章将向小伙伴总结分享BGP的第三个属性——AS_Path属性。

BGP组网案例-AS_Path属性

组网拓扑图

组网拓扑图和地址规划如下图所示。
备注：模拟器采用HCL 5.5.0
 
 
组网设备基础配置

组网设备基础配置主要涉及设备命名和接口IP地址配置。
#SW_1设备基础配置
[H3C]sysname SW_1
[SW_1]interface LoopBack0
[SW_1-LoopBack0] ip address 10.10.0.1 255.255.255.255
[SW_1-LoopBack0]quit
[SW_1]interface LoopBack1
[SW_1-LoopBack1] ip address 192.168.10.1 255.255.255.255
[SW_1-LoopBack1]#
[SW_1-LoopBack1]interface LoopBack2
[SW_1-LoopBack2] ip address 192.168.10.2 255.255.255.255
[SW_1-LoopBack2]#
[SW_1]interface GigabitEthernet1/0/2
[SW_1-GigabitEthernet1/0/2] port link-mode route
[SW_1-GigabitEthernet1/0/2] ip address 10.10.12.1 255.255.255.252
[SW_1-GigabitEthernet1/0/2]quit
#SW_2设备基础配置
[H3C]sysname SW_2
[SW_2]interface LoopBack0
[SW_2-LoopBack0] ip address 10.20.0.1 255.255.255.255
[SW_2-LoopBack0]quit
[SW_2]interface GigabitEthernet1/0/2
[SW_2-GigabitEthernet1/0/2] port link-mode route
[SW_2-GigabitEthernet1/0/2] ip address 10.10.12.2 255.255.255.252
[SW_2-GigabitEthernet1/0/2]quit
[SW_2]interface GigabitEthernet1/0/3
[SW_2-GigabitEthernet1/0/3] port link-mode route
[SW_2-GigabitEthernet1/0/3] ip address 10.20.23.1 255.255.255.252
[SW_2-GigabitEthernet1/0/3]quit
#SW_3设备基础配置
[H3C]sysname SW_3
[SW_3]interface LoopBack0
[SW_3-LoopBack0]ip address 10.30.0.1 255.255.255.255
[SW_3-LoopBack0]quit
[SW_3]interface GigabitEthernet1/0/3
[SW_3-GigabitEthernet1/0/3] port link-mode route
[SW_3-GigabitEthernet1/0/3] ip address 10.20.23.2 255.255.255.252
[SW_3-GigabitEthernet1/0/3]quit
[SW_3]interface GigabitEthernet1/0/4
[SW_3-GigabitEthernet1/0/4] port link-mode route
[SW_3-GigabitEthernet1/0/4] ip address 10.30.34.1 255.255.255.252
[SW_3-GigabitEthernet1/0/4]quit
[SW_3]
#SW_4设备基础配置
[H3C]sysname SW_4
[SW_4]interface LoopBack0
[SW_4-LoopBack0] ip address 10.40.0.1 255.255.255.255
[SW_4-LoopBack0]quit
[SW_4]interface GigabitEthernet1/0/4
[SW_4-GigabitEthernet1/0/4] port link-mode route
[SW_4-GigabitEthernet1/0/4] ip address 10.30.34.2 255.255.255.252
[SW_4-GigabitEthernet1/0/4]quit
[SW_4]

组网设备BGP配置

#SW_1设备BGP配置
[SW_1]bgp 10
[SW_1-bgp-default] router-id 10.10.0.1
[SW_1-bgp-default] peer 10.10.12.2 as-number 20
[SW_1-bgp-default] address-family ipv4 unicast
[SW_1-bgp-default-ipv4] network 192.168.10.1 255.255.255.255
[SW_1-bgp-default-ipv4] network 192.168.10.2 255.255.255.255
[SW_1-bgp-default-ipv4] peer 10.10.12.2 enable
[SW_1-bgp-default-ipv4]quit
[SW_1-bgp-default]quit
[SW_1]save f
Validating file. Please wait...
Saved the current configuration to mainboard device successfully.
[SW_1]
#SW_2设备BGP配置
[SW_2]bgp 20
[SW_2-bgp-default] router-id 10.20.0.1
[SW_2-bgp-default] peer 10.10.12.1 as-number 10
[SW_2-bgp-default] peer 10.20.23.2 as-number 30
[SW_2-bgp-default] address-family i