Even if you want a simple mechanism, I think the bidirectionality and
block numbers would be VERY good ideas. I think these two are critical.
Without either resumption or retransmission, there seem to be many
environments where low complexity is valuable but the system is unlikely
to be able to perform the transfers.
This does edge into the argument about how much size and work it would
be to just use the code for an existing protocol.
Yours,
Joel
On 9/12/17 12:56 AM, Brian E Carpenter wrote:
Hi Joel, thanks for the rapid comments. More in-line:
On 12/09/2017 15:17, Joel M. Halpern wrote:
Given our experience with file transfers, several things seem to be
called for:
1) There should be a mechanism for the sender to initiate. Several of
the use cases you cite are such that the sender would better than the
receiver when it is a good time to send the data.
Yes, certainly. That's behind the mention that the mechanism could
be turned round for upload. Maybe it would be better to call it
push and pull, since ANIMA does not assume a hierarchy.
2) I realize that it does not fit the pattern, but without some sort of
position indication, this seems very fragile. I think you need to come
up with a way to indicate the position.
It wouldn't be hard to add a block number, both for the sending side
and the acknowledgements. But then it would be very tempting to also add
a retransmission mechanism, and look, we've re-invented the wheel. So
we just have to decide where to stop in complexity.
3) Unless we want to restrict this to very local environments, we really
should have a way to resume a failed transfer at the failure point,
rather than start from teh beginning.
Ditto. To be honest I had to stop myself adding such mechanisms, when writing
a quick prototype.
> In particular, without these features, the justification for using GRASP
rather than a better transfer protocol over the ANIMA infrastructure
becomes very weak.
Well, there we might disagree. Or at least, that is the question of scope.
What do we want to assume is already installed on an autonomic node? If it's
a fully-featured host or host-like device, I would expect some existing
mechanism to be available. If it's a bare-bones device, maybe not. But in that
case, we'd want a GRASP-based mechanism to be bare-bones too*. We'd be
interested
in WG opinions about this.
*Just to scale it, the client side that corresponds to the example
in the draft is about 110 lines of Python.
Thanks
Brian
Yours,
Joel
On 9/11/17 9:41 PM, Brian E Carpenter wrote:
Comments welcomed!
-------- Forwarded Message --------
Subject: I-D Action: draft-carpenter-anima-grasp-bulk-00.txt
Date: Mon, 11 Sep 2017 18:32:28 -0700
From: [email protected]
Reply-To: [email protected]
To: [email protected]
A New Internet-Draft is available from the on-line Internet-Drafts directories.
Title : Transferring Bulk Data over the GeneRic Autonomic
Signaling Protocol (GRASP)
Authors : Brian Carpenter
Sheng Jiang
Bing Liu
Filename : draft-carpenter-anima-grasp-bulk-00.txt
Pages : 10
Date : 2017-09-11
Abstract:
This document describes how bulk data may be transferred between
Autonomic Service Agents via the GeneRic Autonomic Signaling Protocol
(GRASP).
The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-carpenter-anima-grasp-bulk/
There are also htmlized versions available at:
https://tools.ietf.org/html/draft-carpenter-anima-grasp-bulk-00
https://datatracker.ietf.org/doc/html/draft-carpenter-anima-grasp-bulk-00
Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.
Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/
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