At 06:32 PM 11/20/00 -0800, Mark Nottingham wrote:
>* Transport - WCIP seems to use a hodge-podge of transports, including HTTP,
> a yet-to-be-described TCP protocol, and multicast. I'd argue that there
> should be one transport, or at most two, if multicast is really necessary.
Did anyone have experience with TIBCO/Rendezvous software (or Globalcast's
software, for that matter). They seem to provide reliable multicast
messaging, a publisher/subscriber model. Could be a transport for cache
invalidation etc.
I'd like to first understand their wide-area-network implications, e.g.,
latency, scalability. Also, the performance of fine-grained message
filtering. Any input?
Dan
> I'm personally doubtful about using multicast, both because of its poor
> deployment and the fact that it requires specifying two separate models
> for using WCIP. It should be noted that I'm not exactly familiar with the
> issues in multicast, but then again IETF is full of people who are, so
> hopefully this issue can be sorted soon.
>
> I'd very much like BXXP to be addedd to the list of possible components to
> reuse (in design issues). It's a much more functional, clean and
> extensible framework than HTTP, from what little I know.
>
>Cheers,
>
>
>
>
>
>On Wed, Nov 15, 2000 at 12:57:41PM -0800, Dan Li wrote:
> > Hi, please take a look of the WCIP draft before the IETF meeting, as we'd
> > spend time on issue discussions and won't cover the draft in detail. This
> > draft is a strawman, at least the following things need more work:
> >
> > - clearly define the relationship of wcip with normal cache-control
> directives.
> >
> > - specify in more detail the role of relay point, especially for channel
> > aggregation. Can we or can we not aggregate heartbeats, possibly but
> > cutting freshness guarantee.
> >
> > - pick a security model. Use SSL, or PGP signature, or both, and also the
> > security of the channel info.
> >
> > - do we need a default port number? pros and cons wrt. to port 80.
> >
> > - are people happy with persistent TCP connection? are people happy with
> > "delta consistency" (vs. eventual consistency, strong consistency, or
> > anything else).
> >
> > - in the absence of a off-the-shelf realtime reliable multicast protocol,
> > can we still run wcip on multicast UDP for scalability. See section 3.2.3.
> >
> > - preloading, log reporting, advanced event notification, programability,
> > ... future stuff on vertical peering and dynamic content
> >
> > What do people think?
> >
> > Dan
> >
> >
> >
> >
> >
> > At 08:12 AM 11/15/00 -0800, Ian Cooper wrote:
> >
> > >>To: IETF-Announce: ;
> > >>From: Internet-Drafts@ietf.org
> > >>Subject: I-D ACTION:draft-danli-wrec-wcip-00.txt
> > >>Date: Wed, 15 Nov 2000 06:41:12 -0500
> > >>
> > >>A New Internet-Draft is available from the on-line Internet-Drafts
> > >>directories.
> > >>
> > >>
> > >> Title : WCIP: Web Cache Invalidation Protocol
> > >> Author(s) : D. Li, P. Cao, M. Dahlin
> > >> Filename : draft-danli-wrec-wcip-00.txt
> > >> Pages : 26
> > >> Date : 14-Nov-00
> > >>
> > >>Cache consistency is a major impediment to scalable content
> > >>delivery. This document describes the Web Cache Invalidation
> > >>Protocol (WCIP) which uses invalidations and updates to keep
> > >>changing objects up to date in web caches. Moreover, it allows
> > >>automatic one-to-may relay and many-to-one aggregation in a CDN
> > >>(content delivery network) environment.
> > >>
> > >>A URL for this Internet-Draft is:
> > >>http://www.ietf.org/internet-drafts/draft-danli-wrec-wcip-00.txt
> > >>
> > >>Internet-Drafts are also available by anonymous FTP. Login with the
> username
> > >>"anonymous" and a password of your e-mail address. After logging in,
> > >>type "cd internet-drafts" and then
> > >> "get draft-danli-wrec-wcip-00.txt".
> > >>
> > >>A list of Internet-Drafts directories can be found in
> > >>http://www.ietf.org/shadow.html
> > >>or ftp://ftp.ietf.org/ietf/1shadow-sites.txt
> > >>
> > >>
> > >>Internet-Drafts can also be obtained by e-mail.
> > >>
> > >>Send a message to:
> > >> mailserv@ietf.org.
> > >>In the body type:
> > >> "FILE /internet-drafts/draft-danli-wrec-wcip-00.txt".
> > >>
> > >>NOTE: The mail server at ietf.org can return the document in
> > >> MIME-encoded form by using the "mpack" utility. To use this
> > >> feature, insert the command "ENCODING mime" before the "FILE"
> > >> command. To decode the response(s), you will need "munpack" or
> > >> a MIME-compliant mail reader. Different MIME-compliant mail
> readers
> > >> exhibit different behavior, especially when dealing with
> > >> "multipart" MIME messages (i.e. documents which have been split
> > >> up into multiple messages), so check your local documentation on
> > >> how to manipulate these messages.
> > >>
> > >>
> > >>Below is the data which will enable a MIME compliant mail reader
> > >>implementation to automatically retrieve the ASCII version of the
> > >>Internet-Draft.
> > >>
> > >>Content-Type: text/plain
> > >>Content-ID: <20001114131241.I-D@ietf.org>
> > >>
> > >>ENCODING mime
> > >>FILE /internet-drafts/draft-danli-wrec-wcip-00.txt
> > >>
> > >><ftp://ftp.ietf.org/internet-drafts/draft-danli-wrec-wcip-00.txt>
> > >
>
>--
>Mark Nottingham, Research Scientist
>Akamai Technologies (San Mateo, CA)
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