Subject: Re: [ipfix-protocol] Template refresh

From: David Moore <[email-masked]>
Date: Thu, 05 Aug 2004 01:06:09 -0700

Stewart Bryant <[email-masked]> writes:

>> From draft-ietf-ipfix-protocol-3.txt
> Section 13. Template Management The following text is specific to the
> sending of Templates
> over unreliable transport protocols:
>
> The Exporting Process sends the Template FlowSet and Options Template
> FlowSet under the following conditions: <snip>
>    3. On a regular basis, the Exporting Process MUST send all the
>    Template Records and Options Template Records to refresh the
>    Collecting Process. Template IDs have a limited lifetime at the
>    Collecting Process and MUST be periodically refreshed.      Two
>    approaches are taken to make sure that Templates get      refreshed
>    at the Collecting Process:         * Every N number of IPFIX
>    Messages.         * On a time basis, so every N number of minutes.
>    Both options MUST be configurable by the user on the Exporting
>    Porcess.      When one of these expiry conditions is met, the
>    Exporting      Process MUST send the Template FlowSet and Options
>    Template.  <end extract>
>
> Should be replaced by:
>
> If the Template Records and Options Template Records are sent using
> a transport protocol that is not fully reliable they MUST be refreshed
> on a regular basis by the Exporting Process which MUST re-send all the
> Template Records and Options Template Records to the Collecting
> Process.

Hi Stewart,

Two things with this change:

1. The text in section 13 of proto-4 (Collecting Process's Side) would
need to be updated as well, since it currently says:

"The life of a template at the Collecting Process is limited to a fixed
refresh timeout. Templates not refreshed from the Exporting Process
within the timeout are expired at the Collecting Process."

2. If the exporting process is not required to refresh templates, then the
collector can never expire a template.  I don't recall seeing anything
in the proto-3 draft (nor quick search in proto-4) where the exporter
can explicitly tell the collector to delete or forget about a template.
If there is no ability to delete no-longer used templates, the collector
may have to allocate resources to large numbers of defunct templates
over time.

-- david

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---

From: Stewart Bryant <[email-masked]>
Date: Mon, 09 Aug 2004 12:28:44 +0100

This will get cleaned up on the next pass.

Stewart