Abstract: Congestion control in InfiniBand network can guarantee high performance and resource utilization．It avoids performance damage of congestion spreading to victim flow．This paper first introduced the InfiniBand congestion control mechanism of ECN (Explicit Congestion Notification)．Then,a new tool named CTBG (Central Traffic Behavior Generator) was proposed to generate congestion traffic from multiple nodes and analyze the result in a central controller mode．In order to further investigate the congestion control behavior of InfiniBand,we proposed the new observation method based on ibdump and wireshark．The experiment indicates the observation method in this paper can observe the InfiniBand congestion control behavior with fine granularity and low cost．This method has important significance for the research of the InfiniBand congestion control mechanism.

Key words: InfiniBand,Congestion control,Observation,ECN,ibdump