Tom,
On 31 Oct 2008, at 17:45, Phelan, Tom wrote:
I've submitted draft-phelan-dccp-natencap-02. You can get the text
from
http://www.phelan-4.com/dccp/draft-phelan-dccp-natencap-02.txt and a
diff-marked version from
http://www.phelan-4.com/dccp/draft-phelan-dccp-natencap-02-diffs.pdf.
The main change is to update RTP over DCCP to add SDP to indicate the
type of DCCP encapsulation to use. Feedback appreciated :-).
In section 3.6, it states that an application SHOULD NOT register
different service codes and port for different combinations of
encapsulation and IP version. Since there is no guidance on when it's
appropriate to deviate from this advice, may I suggest the text
should say MUST NOT instead?
Section 4 hints that the encapsulation of a higher-layer protocol
with DCCP may differ between DCCP-RAW and DCCP-NAT. That seems
undesirable to me - is there a use case for this? If not, I suggest
the text be updated to be "MUST be the same".
Section 5 suggests an SDP attribute to signal the use of DCCP-NAT.
It's not clear why this is needed. I'd expect the operating system to
try both native and UDP-encapsulated connections in parallel for the
DCCP-INIT, and use that which works, rather than applications be
aware of the encapsulation. Wouldn't any choice be a matter of policy
for the OS, not the application?
Cheers,
--
Colin Perkins
http://csperkins.org/
