Subject: [netmod] How to represent durations?

From: Brent Chapman <[email-masked]>
Date: Mon, 27 Jul 2009 13:38:09 +0200

My apologies for coming late to the discussion, but how do you represent
durations (i.e, "30 seconds", "60 minutes", "20 milli-seconds") in NETMOD?

For instance, if I'm setting up an ARP cache
expiration policy for a particular device, I might want to set it to
"10 minutes".  If I'm setting a VRRP failover policy, I might want to
say "30 seconds".  If I want to set a jitter limit parameter on a VOIP
link, I might want to express it in milli-seconds.

-Brent
-- 
Brent Chapman <[email-masked]>
Netomata, Inc. -- www.netomata.com
Making networks more cost-effective, reliable, and flexible by automating
network configuration

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From: Juergen Schoenwaelder <[email-masked]>
Date: Tue, 28 Jul 2009 10:38:21 +0200

On Mon, Jul 27, 2009 at 01:38:09PM +0200, Brent Chapman wrote:

> My apologies for coming late to the discussion, but how do you
> represent durations (i.e, "30 seconds", "60 minutes", "20
> milli-seconds") in NETMOD?

> For instance, if I'm setting up an ARP cache expiration policy for a
> particular device, I might want to set it to "10 minutes".  If I'm
> setting a VRRP failover policy, I might want to say "30 seconds".
> If I want to set a jitter limit parameter on a VOIP link, I might
> want to express it in milli-seconds.

XML schema supports a duration type that has been modelled after some
ISO standard. I can express durations counted in years all the way
down to seconds. This is how a generic type could look like (although
the XSD type falls short on milli-second or micro-second resolutions).

The way we have dealt with this in the past in most MIB modules is to
have data model specific numbers where the data modeler at modeling
time defines the resolution, e.g. defining a leaf with a protocol
timeout expressed in milli-seconds.

Speaking as a document editor, I do not know how a good duration type
looks like (I believe the XSD type is not very useable for us) and so
either someone makes a good concrete proposal now or we should leave
out a generic duration type and leave this for a future revision of
this document.

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1, 28759 Bremen, Germany
Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>