RE: [EFM]Event Time Stamp
Thanks for the explanation!
So this time stamp gives the more or less precise timing of events that are
clumped together. If events are spaced more than 109 (65535/10/60) minutes
apart, they became meaningless. One would imagine this "micro" view needs to
be supplemented by the "macro" view of local time stamping as events are
received.
Perhaps a few sentences to explain this in the standard would be useful?
Thanks again.
-- Yonghong Ren
-----Original Message-----
From: Matt Squire [mailto:MSquire@HatterasNetworks.com]
Sent: Tuesday, August 05, 2003 10:07 PM
To: Yonghong Ren; stds-802-3-efm@ieee.org
Subject: Re: [EFM]Event Time Stamp
Here's my recollection of the justification of timestamping...
The timestamp is not intended to represent the time since system uptime. At
least not for any piece of reliable equipment:) It was added to provide
"relative" times between events for more accuracat reporting (e.g. if source
timestamps X & Y as happening 500 ms apart, thats probably more accurate
than the receiver getting them 650ms apart due to the delay caused by the
limited number of OAM frames). The origin of the utility can be found in
http://www.ieee802.org/3/efm/public/mar03/oam/gerhardt_oam_1_0303.pdf.
- Matt
On Mon, 4 Aug 2003 16:38:59 -0400, Yonghong Ren <ren@appiancom.com> wrote:
> The most recent draft (2D) defines the Event Time Stamp in Event TLV as
> 16-bit, in the unit of 100ms. If we assume this "time reference" to mean
> something like a system uptime, then it's simply not wide enough.
> Interestingly, the Event Time Stamp references section 30.11.1.1.37-40,
> where the time stamps seem to be defined as 32-bit integers. So, perhaps
> it's simply a typographical error?
> I would appreciate any clarification for me. Thanks.
> -- Yonghong Ren
>