[netlmm] Re: timestamps description (was: I-D Action:draft-ietf-netlmm-proxymip6-04.txt)

[Alexandru Petrescu <[e-mail]>]

Sri, thank you for the new version of the draft.

Apparently it's insisted that PMIPv6 should rely on timestamps and time 
synchronization.  I oppose this, and I prefer the draft to not 
RECOMMEND, neither SHOULD, nor MAY relying on time synchronization nor 
timestamps.  But relying on sequence numbers, with a method I've already 
posted.

When this gets agreed in the WG I agree.

Until then, I have some nits about how time use is described in the new 
draft-04.

>    For solving this problem, this specification RECOMMENDS the use of
>    Timestamp option [Section 8.4].  The basic principle behind the use
>    of timestamps in binding registration messages is that the node
>    generating the message inserts the current time-of-day, and the node
>    receiving the message checks that this timestamp is greater than all
>    previously accepted timestamps.

(It's section 8.5 actually.)

>    Timestamp
> 
>       A 64-bit unsigned integer field containing a timestamp.  The value
>       indicates the number of seconds since January 1, 1970, 00:00 UTC,
>       by using a fixed point format.  In this format, the integer number
>       of seconds is contained in the first 48 bits of the field, and the
>       remaining 16 bits indicate the number of 1/64K fractions of a
>       second.

I think it should better say 1/65536 fractions of a second, and not 
1/64K fractions.  Let me say why.  64k means 65535 when talking bits and 
bytes.  If we talk anything else then 64k means 64000 (meters, seconds, 
Hertz, Joules, etc.)

I think we should also say in the draft that the timestamp contains the 
number of seconds measured at GMT (or some other place of your choice) 
since Jan 1st, 1970, 00h00 UTC.  Let me say why.  If we don't say where 
this timestamp was measured then there are different timezones on Earth, 
and a MAG in eg New Delhi will have a different timestamp than a LMA in 
Hyderabad, even if they represent the same moment.

Alex

[e-mail] wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> This draft is a work item of the Network-based Localized Mobility Management Working Group of the IETF.
> 
> 
> 	Title           : Proxy Mobile IPv6
> 	Author(s)       : S. Gundavelli, et al.
> 	Filename        : draft-ietf-netlmm-proxymip6-04.txt
> 	Pages           : 57
> 	Date            : 2007-09-11
> 
> This specification describes a network-based mobility management
> protocol.  It is called Proxy Mobile IPv6 and is based on Mobile IPv6
> [RFC-3775].  This protocol enables mobility support to a host without
> requiring its participation in any mobility related signaling.  The
> design principle in the case of network-based mobility management
> protocol relies on the network being in control of the mobility
> management.  The mobility entities in the network are responsible for
> tracking the movements of the host and initiating the required
> mobility signaling on its behalf.
> 
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-ietf-netlmm-proxymip6-04.txt
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