S6900-54QF-F 配置GRE隧道协议和物理都是Down的解决方法

客户需求：S6900-54QF-F 配置GRE隧道实现两端内网进行互通

出现问题：在S6900-54QF-F配置了GRE 隧道后，协议和物理都是Down的情况，但是2端的tunnel口源目地址互相是可以ping通的

客户的关键配置：

2端GRE配置

interface Tunnel2 mode gre

ip address 172.20.20.6 255.255.255.252

source 119.147.144.172

destination 183.60.141.250

interface Tunnel2 mode gre

ip address 172.20.20.5 255.255.255.252

source 183.60.141.250

destination 119.147.144.172

debug tunnel event看到提示硬件资源不够

*Jul  3 19:13:22:282 2018 GD-DG-LB-BR-6900-1 TUNNEL/7/event:

Tunnel2 can't come up because there is no enough hardware resource.

*Jul  3 19:13:27:281 2018 GD-DG-LB-BR-6900-1 TUNNEL/7/event:

Processing result of operation 2 for Tunnel2: failed.

*Jul  3 19:13:27:282 2018 GD-DG-LB-BR-6900-1 TUNNEL/7/event:

原因：没有配置业务环回组，需要先创建业务类型为Tunnel的业务环回组，将设备上未使用的某个二层以太网接口（接口DOWN不影响）加入该业务环回组。

具体配置如下：

业务环回组典型配置举例

1. 组网需求

Device A上的所有以太网端口都支持Tunnel业务类型，通过配置将端口Ten-GigabitEthernet1/0/1～Ten-GigabitEthernet1/0/3加入到业务环回组中以实现对Tunnel业务类型的支持。

2. 配置步骤

# 创建业务环回组1，并指定其业务类型为Tunnel类型。

<DeviceA> system-view

[DeviceA] service-loopback group 1 type tunnel

# 分别将端口Ten-GigabitEthernet1/0/1～Ten-GigabitEthernet1/0/3加入业务环回组1。

[DeviceA] interface ten-gigabitethernet 1/0/1

[DeviceA-Ten-GigabitEthernet1/0/1] port service-loopback group 1

All configurations on the interface will be lost. Continue?[Y/N]:y

[DeviceA-Ten-GigabitEthernet1/0/1] quit

[DeviceA] interface ten-gigabitethernet 1/0/2

[DeviceA-Ten-GigabitEthernet1/0/2] port service-loopback group 1

All configurations on the interface will be lost. Continue?[Y/N]:y

[DeviceA-Ten-GigabitEthernet1/0/2] quit

[DeviceA] interface ten-gigabitethernet 1/0/3

[DeviceA-Ten-GigabitEthernet1/0/3] port service-loopback group 1

All configurations on the interface will be lost. Continue?[Y/N]:y

[DeviceA-Ten-GigabitEthernet1/0/3] quit

# 创建GRE模式的Tunnel接口1，该接口将自动引用业务环回组1。

[DeviceA] interface tunnel 1 mode gre

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