一种工业以太网交换机ARP老化机制

An ARP Aging Mechanism for Industrial Ethernet Switch

在在交换机转发架构中,数据报文的目的 IP地址一旦写入硬件转发表,数据包将不会再经过TCP/IP协议来转发,而是由交换芯片完成三层转发。当数据报文由交换芯片转发后TCP/IP的ARP处理状态机就不会进入probe状态,而是进入stale状态,然后该ARP表项就会被删除。当ARP表在"有人使用"的情况下,这种处理会引起频繁删除添加ARP表和硬件转发表,从而导致网络震荡。针对此问题,设计了一种交换机ARP老化的实现方法,当ARP对应的IP设备不在网络中可以被老化,回收ARP资源;对于那些在网络中存在的设备,不做老化处理,保证他们在网络中使用的流畅性。

In the switch forwarding architecture,once the destination IP address of the data packet is written into the hardware forwarding table,the packet will no longer be forwarded through the TCP/IP protocol,but will be forwarded by the switch chip.When the data packet is forwarded by the switching chip,the ARP processing state machine of TCP/IP will not enter the probe state,but will enter the stale state,and then the ARP entry will be deleted.ARP tables will be″used″in the case,this processing will cause frequent deletions to add ARP tables and hardware forwarding tables,resulting in network shock.In order to solve this problem,this paper designs an implementation method of switch ARP aging,when the IP devices corresponding to ARP are not in the network,the ARP resources can be recovered.For those devices that exist in the network,there is no aging treatment to ensure the fluency of their use in the network.