
bandwidth for the exact same transmissions as UDP. This can, con-
ceivably, bring the network to its collective knees.
If the request is for live content, three options are attempted by
the client. First, the client attempts a multicast type connection.
A special attribute of particular firewalls allows multicast so whether
or not this connection type succeeds depends on the firewall. If mul-
ticast is not available, the client will attempt to open a UDP channel
for RTSP or PNA on ports 6,970 through 6,999. If UDP is not
allowed, the client falls back on TCP over port 554.
9.6 Summary
Many legacy technologies, such as FTP and Telnet, have been ren-
dered ...