[Olsr-users] 0.5.6 Routes disappear after 4 mins of uptime, then all OK - suspect clock sync

Henning Rogge (spam-protected)
Wed Sep 3 09:01:54 CEST 2008

Am Dienstag 02 September 2008 23:22:13 schrieb Bernd Petrovitsch:
> Risking to over-engineer the issue:
> The key question is IMHO:
> What are the largest timeouts/time differences to be handled (in the
> foreseeable future)?
The maximum time value used by OLSR and OLSRv2 (timetlv draft) is
  ~ 4.0 * 10^9 * C
(and C is is a constant like 1/1024).

So we can easily fit any time interval into 32 bit.

> If they fit easily in 32bit, we should keep them in 32bit (read: use
> "unsigned int") to avoid costly 53bit operations on 32bit hardware (as
> all the small WLAN routers are where 64bit ints hurts much more than on
> quad-core-4-GHz).
> The price to pay: Look over the source and make sure to not simply
> compare two timestamps as in "a < b" but compare as "a - b < 1<<31" (or
> so). Overflow is then a non-issue.
Yes, we could do this similar to the OLSR sequence number overflow, so that 
there is no overflow issue. :)


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