核心和楼层交换机都是傻瓜型的，不能配置。 
网关在AR路由器上，用户均通过傻瓜路由器接入，傻瓜路由器均为tp-link类型的，傻瓜路由器的IP分为两个网段，分别为190.131.1.0/16和190.131.3.0/16，傻瓜路由器下面的用户通过DHCP获得IP，并通过傻瓜路由器自带的NAT功能转换IP后接入网络。 

问题： 
AR2240 下面的内网段有时不能正常访问外网 

查看cpu-defend，发现有丢包 
display cpu-defend statistic 
----------------------------------------------------------------------- 
Packet Type               Pass Packets        Drop Packets 
----------------------------------------------------------------------- 
8021X                                0                   0 
arp-miss                          5744                   0 
arp-reply                         3903                   0 
arp-request                     448252                1390 
bfd                                  0                   0 

查看trapbuffer，发现有ARP冲突 
#Dec  9 2014 10:09:34+00:00 253_HW_AR2240 ARP/4/ARP_IPCONFLICT_TRAP:OID 1.3.6.1.4.1.2011.5.25.123.2.6 ARP detects IP conflict. (IP address=190.131.3.131, Local interface=GigabitEthernet0/0/1, Local MAC=0017-59de-b688, Local vlan=0, Local CE vlan=0, Receive interface=GigabitEthernet0/0/1, Receive MAC=78a1-067c-7dc1, Receive vlan=0, Receive CE vlan=0, IP conflict type=Remote IP conflict). 
#Dec  9 2014 10:01:44+00:00 253_HW_AR2240 ARP/4/ARP_IPCONFLICT_TRAP:OID 1.3.6.1.4.1.2011.5.25.123.2.6 ARP detects IP conflict. (IP address=190.131.3.130, Local interface=GigabitEthernet0/0/1, Local MAC=0017-59de-b688, Local vlan=0, Local CE vlan=0, Receive interface=GigabitEthernet0/0/1, Receive MAC=78a1-067c-7dbb, Receive vlan=0, Receive CE vlan=0, IP conflict type=Remote IP conflict). 
#Dec  9 2014 09:49:28+00:00 253_HW_AR2240 ARP/4/ARP_IPCONFLICT_TRAP:OID 1.3.6.1.4.1.2011.5.25.123.2.6 ARP detects IP conflict. (IP address=190.131.3.131, Local interface=GigabitEthernet0/0/1, Local MAC=0017-59de-b688, Local vlan=0, Local CE vlan=0, Receive interface=GigabitEthernet0/0/1, Receive MAC=78a1-067c-7dc1, Receive vlan=0, Receive CE vlan=0, IP conflict type=Remote IP conflict). 
#Dec  9 2014 09:34:04+00:00 253_HW_AR2240 ARP/4/ARP_IPCONFLICT_TRAP:OID 1.3.6.1.4.1.2011.5.25.123.2.6 ARP detects IP conflict. (IP address=190.131.3.133, Local interface=GigabitEthernet0/0/1, Local MAC=7427-eae4-275b, Local vlan=0, Local CE vlan=0, Receive interface=GigabitEthernet0/0/1, Receive MAC=0017-59de-b688, Receive vlan=0, Receive CE vlan=0, IP conflict type=Remote IP conflict). 

查看ARP表 
<253_HW_AR2240> 
IP ADDRESS      MAC ADDRESS     EXPIRE(M) TYPE        INTERFACE   VPN-INSTANCE 
                                          VLAN/CEVLAN PVC                    
190.131.1.107   0014-5e7a-75b4  20        D-0         GE0/0/1 
190.131.3.121   0017-59de-b688  2         D-0         GE0/0/1 
190.131.1.112   cc34-2999-9bbf  17        D-0         GE0/0/1 
190.131.3.120   7427-eae4-275b  20        D-0         GE0/0/1 
190.131.1.109   0014-5e19-a483  13        D-0         GE0/0/1 
190.131.1.199   d815-0d38-3d3d  3         D-0         GE0/0/1 
190.131.1.101   0014-5e7a-7574  19        D-0         GE0/0/1 
190.131.1.206   0022-3fa5-b237  4         D-0         GE0/0/1 
190.131.3.6     0017-59de-b688  18        D-0         GE0/0/1 
190.131.1.6     90fb-a61e-13e5  16        D-0         GE0/0/1 //这个是正常的傻瓜路由器的MAC 
190.131.1.233   7427-ea3d-e4ef  20        D-0         GE0/0/1 
190.131.1.130   0060-6e9a-0d23  2         D-0         GE0/0/1 //这个应该是正常的傻瓜路由器的MAC 
190.131.1.50    4437-e676-91aa  2         D-0         GE0/0/1 
190.131.3.130   0017-59de-b688  17        D-0         GE0/0/1 
190.131.3.132   0021-272e-eb43  14        D-0         GE0/0/1 
190.131.3.131   0017-59de-b688  5         D-0         GE0/0/1 
190.131.3.133   0017-59de-b688  10        D-0         GE0/0/1