A multicast stream is distributed over a specific number of
routers in a network, which is determined by the time-to-live (TTL)
value. The time-to-live value decreases every time the content
passes through a router. When the value reaches zero, the multicast
stream travels no further. The WMS Multicast Data Writer plug-in
has the following preset time-to-live values based on the type of
distribution:
1 : Local network
32 : Intranet
64 : Internet, intra-continent
128 : Internet, inter-continent
255 : Maximum-allowed value
You may also specify any whole number between 1 and 255 to meet
the needs of your multicast.
If you use an IPv6 multicast address, the time-to-live value is
included in the first field of the address. For example, the first
field in the address FF01:0000:0000:0000:0000:0000:0000:0000 is
FF01, which indicates the address is locally scoped, meaning
that the content is restricted to the local computer and the
time-to-live value is set to 1. The following list shows the
standard first field values and their corresponding scopes:
FF01 : local node or computer
FF02 : local area network (LAN)
FF05 : local site
FF08 : organization
FF0E : Internet
Notes
IP addresses in the range 239.*.* are
administratively scoped, which means that TTL values do not
have a special meaning. For example, the value 32 does not limit
the stream to an intranet, and the value 64 does not limit the
stream to the intra-continent Internet. The TTL assignment should
be used to limit addresses in the range 239.192.000.000 through
239.255.255.255 to a single organization, and addresses from
239.255.000.000 through 239.255.255.255 to a single site.
Multicast streaming and the WMS Multicast Data
Writer plug-in are available only if Windows Media Services 9
Series is running on the following editions of the operating
system: Windows Server 2003, Enterprise Edition and Windows Server
2003, Datacenter Edition. If you are running Windows Server 2003,
Standard Edition, these features are not supported.
Notes