The user name should be in a form that a program such as "finger" or
"talk" could use, i.e., it typically is the login name rather than
the personal name. The host name is not necessarily identical to the
one in the participant's electronic mail address.
This syntax will not provide unique identifiers for each source if an
application permits a user to generate multiple sources from one
host. Such an application would have to rely on the SSRC to further
identify the source, or the profile for that application would have
to specify additional syntax for the CNAME identifier.
If each application creates its CNAME independently, the resulting
CNAMEs may not be identical as would be required to provide a binding
across multiple media tools belonging to one participant in a set of
related RTP sessions. If cross-media binding is required, it may be
necessary for the CNAME of each tool to be externally configured with
the same value by a coordination tool.
Application writers should be aware that private network address
assignments such as the Net-10 assignment proposed in RFC 1597 [17]
may create network addresses that are not globally unique. This would
Schulzrinne, et al Standards Track [Page 33]
RFC 1889 RTP January 1996
lead to non-unique CNAMEs if hosts with private addresses and no
direct IP connectivity to the public Internet have their RTP packets
forwarded to the public Internet through an RTP-level translator.
(See also RFC 1627 [18].) To handle this case, applications may
provide a means to configure a unique CNAME, but the burden is on the
translator to translate CNAMEs from private addresses to public
addresses if necessary to keep private addresses from being exposed.
6.4.2 NAME: User name SDES item
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NAME=2 | length | common name of source ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This is the real name used to describe the source, e.g., "John Doe,
Bit Recycler, Megacorp". It may be in any form desired by the user.
For applications such as conferencing, this form of name may be the
most desirable for display in participant lists, and therefore might
be sent most frequently of those items other than CNAME. Profiles may
establish such priorities. The NAME value is expected to remain
constant at least for the duration of a session. It should not be
relied upon to be unique among all participants in the session.
6.4.3 EMAIL: Electronic mail address SDES item