Fwd: RE: Distribution CPG Protocol - Some Thoughts

[Stephen Thomas <stephen.thomas@transnexus.com>]

Date: Thu, 4 Jan 2001 21:06:39 -0500 (EST)
From: Oliver Spatscheck <spatsch@research.att.com>

Tomlinson, Gary writes:
  >
  > General comment:  I think this thread scope is beyond the narrow design 
team
  > and should be posted to general list cdn@ops.ietf.org.
  >

ACK


  >
  > On Thursday, January 04, 2001  @1:08 PM Oliver Spatscheck wrote:
  > >I guess this question could be addressed in the redirection protocol which
  > >opens up an interesting question: How does the redirection system learns
  > which
  > >surrogates are actually participating at each point in time? If for
  > example, we
  > >agree that we allow surrogates to cache content even if the content
  > provider
  > >knows that he will never select that surrogate in its redirection 
system we
  > >can push the entire decision process into the redirection system and go
  > with
  > >a content advertising method.  (However, we will still need feedback 
to the
  > >redirection system as to which surrogates or group of surrogates are
  > willing to
  > >accept redirections.)
  >
  > I don't see on-line (aka real-time) feed back as being true real-time
  > granularity per transaction but rather batched and summarized on regular
  > time intervals.  The summaries would include information such as reserve
  > capacity in the CDN, current cost, QoS by service types {streaming media,
  > HTTP, etc).  The thing I'm struggling with on the feed back is whether it
  > belongs in distribution or accounting protocols.   What I mean here is,
  > should distribution be involved in the operational support system at 
all, or
  > should it be limited to service delivery only?
  >

I agree with you that we won't need per transaction real time feedback for the
purpose of direction (we might need it to fulfill legal requirements for on
line gambling ....), however, we need fairly fast feedback of the sort CDN A
is covering network B in region C with available capacity D for service E.
Otherwise the direction system will not know how to direct. I guess we hit the
area in which our separation of tasks becomes kind of fuzzy. Should the
information which is required to facilitate distribution and direction
decisions (like available surrogates capacity of a CDN in particular regions)
be gathered in the distribution, direction or accounting system.  If the
answer is the accounting system then it makes no sense to advertise content or
surrogates in the distribution system. The decision is then based on
information in the accounting system and the distribution system has the sole
purpose of delivering the data to the surrogate not of selecting the data or
the surrogate. Is that what we want? The term accounting system does not
really sound like it would provide information like which CDN provides
surrogates in which region, so if this is our intend we might reconsider
that name.... .

Oliver
p.s I will try to use direction instead of redirection in the future .... .