GRE

.5  GRE典型配置举例

1.5.1  GRE over IPv4隧道典型配置举例

1. 组网需求

Router A和Router B分别连接IPv4私有网络Group 1和Group 2。这两个私有网络都使用私网地址，且属于同一个VPN。通过在Router A和Router B之间建立GRE隧道，实现两个私有网络的互联。

2. 组网图

图1-7 GRE over IPv4隧道应用组网图

3. 配置步骤

(1)     配置Router A

# 创建Tunnel0接口，并指定隧道模式为GRE over IPv4隧道。

<RouterA> system-view

[RouterA] interface tunnel 0 mode gre

# 配置Tunnel0接口的IP地址。

[RouterA-Tunnel0] ip address 10.1.2.1 255.255.255.0

# 配置Tunnel0接口的源端地址（Router A的GigabitEthernet2/0/2的IP地址）。

[RouterA-Tunnel0] source 1.1.1.1

# 配置Tunnel0接口的目的端地址（Router B的GigabitEthernet2/0/2的IP地址）。

[RouterA-Tunnel0] destination 2.2.2.2

[RouterA-Tunnel0] quit

# 配置从Router A经过Tunnel0接口到Group 2的静态路由。

[RouterA] ip route-static 10.1.3.0 255.255.255.0 tunnel 0

(2)     配置Router B

# 创建Tunnel0接口，并指定隧道模式为GRE over IPv4隧道。

<RouterB> system-view

[RouterB] interface tunnel 0 mode gre

# 配置Tunnel0接口的IP地址。

[RouterB-Tunnel0] ip address 10.1.2.2 255.255.255.0

# 配置Tunnel0接口的源端地址（Router B的GigabitEthernet2/0/2的IP地址）。

[RouterB-Tunnel0] source 2.2.2.2

# 配置Tunnel0接口的目的端地址（Router A的GigabitEthernet2/0/2的IP地址）。

[RouterB-Tunnel0] destination 1.1.1.1

[RouterB-Tunnel0] quit

# 配置从Router B经过Tunnel0接口到Group 1的静态路由。

[RouterB] ip route-static 10.1.1.0 255.255.255.0 tunnel 0

4. 验证配置

# 查看Router A的Tunnel接口状态。

[RouterA] display interface tunnel 0

Tunnel0

Current state: UP

Line protocol state: UP

Description: Tunnel0 Interface

Bandwidth: 64kbps

Maximum Transmit Unit: 1476

Internet Address is 10.1.2.1/24 Primary

Tunnel source 1.1.1.1, destination 2.2.2.2

Tunnel keepalive disabled

Tunnel TTL 255

Tunnel protocol/transport GRE/IP

    GRE key disabled

    Checksumming of GRE packets disabled

Output queue - Urgent queuing: Size/Length/Discards 0/100/0

Output queue - Protocol queuing: Size/Length/Discards 0/500/0

Output queue - FIFO queuing: Size/Length/Discards 0/75/0

Last clearing of counters: Never

Last 300 seconds input rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec

Last 300 seconds output rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec

Input: 0 packets, 0 bytes, 0 drops

Output: 0 packets, 0 bytes, 0 drops

# 查看Router B的Tunnel接口状态。

[RouterB] display interface tunnel 0

Tunnel0

Current state: UP

Line protocol state: UP

Description: Tunnel0 Interface

Bandwidth: 64kbps

Maximum Transmit Unit: 1476

Internet Address is 10.1.2.2/24 Primary

Tunnel source 2.2.2.2, destination 1.1.1.1

Tunnel keepalive disabled

Tunnel TTL 255

Tunnel protocol/transport GRE/IP

    GRE key disabled

    Checksumming of GRE packets disabled

Output queue - Urgent queuing: Size/Length/Discards 0/100/0

Output queue - Protocol queuing: Size/Length/Discards 0/500/0

Output queue - FIFO queuing: Size/Length/Discards 0/75/0

Last clearing of counters: Never

Last 300 seconds input rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec

Last 300 seconds output rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec

Input: 0 packets, 0 bytes, 0 drops

Output: 0 packets, 0 bytes, 0 drops

# 从Router B可以Ping通Router A上GigabitEthernet2/0/1接口的地址。

[RouterB] ping -a 10.1.3.1 10.1.1.1

Ping 10.1.1.1 (10.1.1.1) from 10.1.3.1: 56 data bytes, press CTRL_C to break

56 bytes from 10.1.1.1: icmp_seq=0 ttl=255 time=11.000 ms

56 bytes from 10.1.1.1: icmp_seq=1 ttl=255 time=1.000 ms

56 bytes from 10.1.1.1: icmp_seq=2 ttl=255 time=0.000 ms

56 bytes from 10.1.1.1: icmp_seq=3 ttl=255 time=0.000 ms

56 bytes from 10.1.1.1: icmp_seq=4 ttl=255 time=0.000 ms

--- Ping statistics for 10.1.1.1 ---

5 packet(s) transmitted, 5 packet(s) received, 0.0% packet loss

round-trip min/avg/max/std-dev = 0.000/2.400/11.000/4.317 ms