RE: [dccp] Comparison of RTP/UDP and RTP/DCCP

["Phelan, Tom" <tphelan at sonusnet.com>]

Hi Aylin,

As far as using an application layer adaptation module, yes, you still need to 
adapt at the application layer.  When DCCP reduces the allowed maximum transmit 
rate below what you're currently sending, you'll need to shed resolution, or some 
other technique (dropping layers is a good approach).

With DCCP however, you won't need to monitor drop rate at the application layer; 
you simply respond to the maximum transmit rate allowed by DCCP.  This could be 
done with some explicit exchange with the DCCP layer, or an implicit method based 
on application layer buffers, as described in draft-ietf-dccp-tfrc-media.

As far as judging the performance of DCCP versus UDP, there are DCCP 
implementations for Linux and FreeBSD (at various quality levels, but getting 
good, I believe), and there is a TFRC module for ns.  More interesting though, is 
how to make the judgment.  DCCP/TFRC has fair sharing of the network with TCP 
apps as its primary motivation.  Your UDP method probably has good application 
operation as its primary motivation.  Should the comparison be made on the basis 
of application performance only?  Or is some two-dimensional comparison 
necessary?

Tom Phelan

-----Original Message-----
From: dccp-bounces at ietf.org [mailto:dccp-bounces at ietf.org]On Behalf Of Aylin Kantarci
Sent: Friday, July 29, 2005 4:45 AM
To: dccp at ietf.org
Subject: [dccp] Comparison of RTP/UDP and RTP/DCCP


Hello,
 
I have implemneted a streaming software on RTP/UDP. 
How can I compare its performance with RTP/DCCP?
With RTP/UDP I am using an adaptation module for congestion control. 
I am using a scalable codec and  the adaptation module drops layers in case of congestion.
With RTP/DCCP, do I still need an adaptation module? 
What kind of tests are required in order to successfully compare the performance  of  UDP and DCCP?
Is simulation a better technique?  If so, is there a simulation environment with which I can perform the tests?
Regards
 
Yrd. Doc. Dr. Aylin Kantarcı
http://egeweb.ege.edu.tr/~kantarci
Bilgisayar Muhendisliği Bölümü 
Ege Üniversitesi, IZMIR
Tel: 0232 3434000-5316