The hall network is slow especially in the evening because the network traffic is the busiest at that time. Some hall users are using excessively network bandwidth when they download or upload large files eg. videos so other hall users cannot get on the network. The hall network usage policy is specified here.
The hall network can be slow due to port scanning activities from other users' computers which are infected by a virus/spyware.
If you experience a slow network in any of the halls, please report to email@example.com.