GRE over GRE配置

需求：总部与分支之间可以互访；分支之间不访问。

PE-1、PE-2之间访问通过GRE隧道；PE-1、PE-3之间访问通过GRE over GRE隧道（不仅在公网实现数据封装，在私网也实现数据封装），

即PE-1访问PE-3时，PE-1到PE-2之间的流量是双层GRE。

PE-1:

#

 sysname PE-1

#

interface LoopBack0

 ip address 1.1.1.1 255.255.255.255

#

interface GigabitEthernet0/0

 ip address 10.1.1.1 255.255.255.252

#

interface GigabitEthernet0/1

 ip address 192.168.1.1 255.255.255.0

#

interface Tunnel0 mode gre

 ip address 172.16.1.1 255.255.255.252

 source 10.1.1.1

 destination 10.1.1.2

#

interface Tunnel1 mode gre

 ip address 172.17.1.1 255.255.255.252

 source 1.1.1.1

 destination 2.2.2.2

#

PE-2:

#

 sysname PE-2

#

interface GigabitEthernet0/0

 ip address 10.1.1.2 255.255.255.252

#

interface GigabitEthernet0/1

 ip address 10.1.2.2 255.255.255.252

#

interface GigabitEthernet0/2

 ip address 192.168.2.1 255.255.255.0

#

interface Tunnel0 mode gre

 ip address 172.16.1.2 255.255.255.252

 source 10.1.1.2

 destination 10.1.1.1

#

 ip route-static 1.1.1.1 32 Tunnel0

 ip route-static 2.2.2.2 32 10.1.2.1

 ip route-static 192.168.1.0 24 Tunnel0

#

PE-3:

#

 version 7.1.064, Release 0821P11

#

 sysname PE-3

#

interface LoopBack0

 ip address 2.2.2.2 255.255.255.255

#

interface GigabitEthernet0/0

 ip address 10.1.2.1 255.255.255.252

#

interface GigabitEthernet0/1

 ip address 192.168.3.1 255.255.255.0

#

interface Tunnel0 mode gre

 ip address 172.17.1.2 255.255.255.252

 source 2.2.2.2

 destination 1.1.1.1

#

 ip route-static 1.1.1.1 32 10.1.2.2

 ip route-static 192.168.1.0 24 Tunnel0

#

测试：

<ZongBu>ping 192.168.3.2

Ping 192.168.3.2 (192.168.3.2): 56 data bytes, press CTRL+C to break

56 bytes from 192.168.3.2: icmp_seq=0 ttl=253 time=4.000 ms

56 bytes from 192.168.3.2: icmp_seq=1 ttl=253 time=2.000 ms

GRE Tunnel两端的源IP地址和目的IP地址要对应。