Question & Answer: Slow Internet

According to our system log, 8:00pm to 1:00am are the peak hours of
Internet usage. More than 3000 users (using VPN or modem connections)
are connecting online during this period. In general, our network can
support the normal activities of these users with reasonable response
time.

However, in mid-February, our network equipment detected that some
ResNet and remote users generated a huge amount of network
traffic/packets in our network. This made our network router extremely
busy. Hence, you might have experienced a slow response during this
period too. 

To rectify the situation, we took prompt action to identify where these
abnormal traffic/packets were generated from and immediately disabled
the corresponding network ports/access. We also suspended the CWEM
accounts of the concerned users to prevent them from using other access
points to dump packets to our network. 

One of the major reasons that a computer generates abnormal
traffic/packets is that it is infected by virus. Hence, we urge you to
install an appropriate anti-virus scanner and update its virus pattern
file regularly. Please check http://avcenter.itsc.cuhk.edu.hk for the
anti-virus scanner details.

Connection to the Internet

The University's connections to the Internet - 96Mbps Internet links and
45 Mbps Internet2 links - are shared among the eight HARNET (Hong Kong
Academic and Research Network) institutions. As demand for access to the
Internet is rising, a bandwidth allocation policy and charging
arrangement has been implemented to ensure that the bandwidth of the
HARNET's shared Internet link is fairly distributed and suitably
managed. The primary purpose of instituting this policy is to regulate
Internet usage so that the service is fairly used, especially when the
link is congested. 

To reduce Internet bandwidth congestion, we established a proxy server
(http://www.cuhk.edu.hk/itsc/howto/proxy) in February 1998 to cache
frequently-accessed data from outside CUHK and provide shorter response
times for second and subsequent access to the same document. We also
have an additional 1Gbps connection to the Hong Kong Internet eXchange
(HKIX) (http://www.hkix.net) so that we can exchange intra-Hong Kong
traffic locally without routing through the Internet. These
implementations aim at reducing the chance of duplicating retrieval of
the same data from overseas and helping to make more efficient use of
bandwidth. 

However, staff and students may still sometimes experience a slow speed.
Statistics show that more and more University staff and students make
use of the Internet in their daily work, thus making our network
increasingly congested. In order to alleviate the situation, we would
like to urge you not to abuse the network in sending and/or obtaining
excessive amount of data. Furthermore, ITSC will always monitor the
network traffic volume very closely and will take necessary actions to
isolate individual users/servers/subnets which are causing excessive
network traffic from our network.

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