At 11:32 AM 8/13/2001, Jayanth Mysore wrote:
My understanding is that the OPES box is an application level
intermediary, that terminates connections from/to the origin server and
the client. Further there isn't anything that prevents multiple such boxes
to be in the path between the origin server and the client.
If my understanding is correct, I believe it will be important for OPES
boxes that are involved in a given session to discover each other and have
an understanding of what each is doing to the content. This will be
especially important in long running streaming media sessions where
"end-to-end" feedback is used by a source to dynamically readjust its
rate/the content's format etc. Consider the following scenario :
<- -C_OPES1.1--> <-------C_OPES1.2----->
(origin server)---(opes1)-------(opes2)-----------(client)
<-----------C_OPES2.1------> <--C_OPES2.2-->
opes1 : An OPES intermediary in the origin server's authoritative domain
opes2: An OPES intermediary in the client's authoritative domain
C_OPES1.1 : An "end-to-end" connection between the origin server and opes1
C_OPES1.2: An "end-to-end" connection between opes1 and the client
Yes, sounds a lot like the existing operational model with reverse proxys and
proxys.... Consistent with Erickson's I-D.
In this scenario,let's say opes1 measures the goodput of C_OPES1.2 and
uses this estimate to transcode the stream. Likewise, opes2 modifies the
stream based on the goodput estimate on C_OPES2.2. Each of the OPES boxes
could independently transcode the stream resulting in unstable operation
in the worst case and super-degradation of the content quality in the best
case.
I am not sure who would pay for such a service. Anyway, I hear a need for
something along the lines of performance expectations.....
Am I getting something wrong here ?
I do not see how this proposed WG can characterize what is a "good service". I
think we want to outline the rules and "failure modes" so that "bad services'
do not impact others ...
- Jayanth
--
Jayanth P. Mysore
Networks and Infrastructure Research Laboratory,
Motorola
Labs
Phone : (847) 576-8561
Michael W. Condry
Director, Network Edge Technology