[ns] Broken link in homepage

["Nikolaos Katsarakis Austauschstud. (M. Schweigel)" <katsarak@ifn.et.tu-dresden.de>]

Hello,

I am trying to access the link

'additional docs:
        ns tutorial and other presentation slides '
(http://www.isi.edu/nsnam/ns/tutorial.html)

and I get the message
'Not Found

The requested object does not exist on this server. The link you
followed is either outdated, inaccurate, or the
server has been instructed not to let you have it. Please inform the
site administrator of the referring page.'

Could somebody plz check if it is working?

Thanks

Nick