如下L3XC插件功能测试拓扑：

 |--------------|           |--------------|          |--------------|
 |              |           |              |          |              |
 |     PC1      |-----------|     VPP      |----------|     PC2      |
 |              |           |              |          |              |
 |--------------|           |--------------|          |--------------|
    11.1.2.2              11.1.1.1      12.1.1.1         12.1.1.100
                          TG3/0/0       TG3/0/1 

VPP版本

vpp# show version
vpp v21.10.1-release built by root on 4f6ead0c141f at 2021-11-17T14:25:30

设置VPP接口地址：

vpp# set interface state TenGigabitEthernet3/0/0 up
vpp# set interface state TenGigabitEthernet3/0/1 up
vpp# 
vpp# set interface ip address TenGigabitEthernet3/0/0 11.1.1.1/16
vpp# set interface ip address TenGigabitEthernet3/0/1 12.1.1.1/16

设置l3xc，由TG3/0/0进来的流量，转发到TG3/0/1接口的网关地址12.1.1.100；反之，由TG3/0/1进来的流量转发到TG3/0/0接口的网关地址11.1.2.2。如下：

vpp# l3xc add ip4 TenGigabitEthernet3/0/0 via 12.1.1.100 TenGigabitEthernet3/0/1
vpp#
vpp# l3xc add ip4 TenGigabitEthernet3/0/1 via 11.1.2.2 TenGigabitEthernet3/0/0

显示l3xc配置信息：

vpp# show l3xc
l3xc:[0]: TenGigabitEthernet3/0/0
    path-list:[222] locks:1 flags:shared,no-uRPF, uPRF-list:103 len:1 itfs:[2, ]
      path:[226] pl-index:222 ip4 weight=1 pref=0 attached-nexthop:  oper-flags:resolved,
        12.1.1.100 TenGigabitEthernet3/0/1
      [@0]: ipv4 via 12.1.1.100 TenGigabitEthernet3/0/1: mtu:9000 next:4 flags:[] 6891d06265230060e07a6c790800

  [@1]: dpo-load-balance: [proto:ip4 index:219 buckets:1 uRPF:-1 to:[0:0]]
      [0] [@5]: ipv4 via 12.1.1.100 TenGigabitEthernet3/0/1: mtu:9000 next:4 flags:[] 6891d06265230060e07a6c790800
l3xc:[1]: TenGigabitEthernet3/0/1
    path-list:[223] locks:1 flags:shared,no-uRPF, uRPF-list: None
      path:[227] pl-index:223 ip4 weight=1 pref=0 attached-nexthop:  oper-flags:resolved,
        11.1.2.2 TenGigabitEthernet3/0/0
      [@0]: ipv4 via 11.1.2.2 TenGigabitEthernet3/0/0: mtu:9000 next:3 flags:[] 6891d06265220060e07a6c780800

  [@1]: dpo-load-balance: [proto:ip4 index:220 buckets:1 uRPF:-1 to:[0:0]]
      [0] [@5]: ipv4 via 11.1.2.2 TenGigabitEthernet3/0/0: mtu:9000 next:3 flags:[] 6891d06265220060e07a6c780800

PC1与PC2之间流量可通。