Kevin L. Mitchell writes:
> On Wed, 2006-07-26 at 18:26 -0700, Entrope wrote:
> > Send inter-server PINGs and PONGs with high priority.
>
> Um...one side effect of this will be to reduce the utility of the AsLL
> results. Now we'll know the asymmetric link latency for the high
> priority band, but the low priority band may be backed up processing a
> burst or other backlog...and I feel that should show up in the AsLL
> results......
>
> Other thoughts?
That occurred to me. Ideally we would have both; manually initiated
ASLLs already use high priority messages.
My guess is that if the burst completes within some time -- probably
10 to 30 seconds -- it is evidence that the link is good enough to use
given the size of the network, and that later reduction in link speed
is probably a temporary problem. In that case, we would only want to
squit if the route goes entirely away or if the problem persists for
some fairly long time.
If we never get around to putting "some fairly long time" analysis in
the ircd, locally opered bots could map network latencies using
privmsgs and implement the admin's policies based on those numbers.
Making link liveness decisions, rather than quality decisions, based
on the low priority latency may be a poor approximation; it also gives
the admin less freedom in setting linking policy.
Going back to "ideally we would have both", I can imagine allowing the
admin to set latency tolerances at several levels. For example:
high [priority] pingfreq = 5 seconds, below 20 seconds for 180
seconds, below 60 seconds;
low [priority] pingfreq = 5 seconds, below 90 seconds for 180
seconds, below 120 seconds;
This would make the ircd measure both high- and low-priority link
latency (HPLL, LPLL respectively) every five seconds, unless a ping is
pending at the priority. If the HPLL exceeds 60 seconds, or the LPLL
exceeds 120 seconds, the link would be squit immediately. Once the
HPLL is at least 20 seconds, a timer or flag is set; if the HPLL stays
above 20 seconds for at least 180 seconds, the link is squit. The
LPLL "below 90 seconds for 180 seconds" is similar.
Entrope
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