Transport Client 不轮询

The TransportClient connects remotely to an Elasticsearch cluster using the transport module. It does not join the cluster, but simply gets one or more initial transport addresses and communicates with them in round robin fashion on each action (though most actions will probably be "two hop" operations).
 
按照官方说法，TransportClient 会轮询transport addresses，但在实际中我发现，经常是某一台负载比较高。我配置了3个ip，没有开启嗅探。


 
请问大神知道是什么情况吗？