After download the NetSight 6.2.0.183, the snmp timeout problem does not reslove.
I found it was caused by search some Enterasys MIB on Extreme Summit Switch.
Uncheck the Enterasys MIB option, the compass search function works great with out any error finally.
![](https://d1uyvls174j03l.cloudfront.net/extremenetworks-us/attachment/RackMultipart20150216-959-epabux-NetSight_Compass%E6%90%9C%E5%B0%8B%E8%A8%AD%E5%AE%9A_inline.png)