Primary route confusion

Ondrej Zajicek santiago at crfreenet.org
Fri Sep 21 15:52:26 CEST 2018


On Fri, Sep 21, 2018 at 11:58:41AM +0000, Kenth Eriksson wrote:
> So the preference value in BIRD is not the same as administrative
> distance? I believe both Juniper and Cisco treats lower preference
> value / administrative distance value as a more preferred route.
> 
> 
> https://www.juniper.net/documentation/en_US/junos/topics/reference/general/routing-protocols-default-route-preference-values.html
> 
> Is preference value inverted in BIRD?

It has same position/usage as administrative distance in Juniper/Cisco,
but it is inverted (lower is better) relative to them.

Generally, for property called 'metric' or 'distance' it makes sense that
lower is better, while for 'preference' it makes sense that higher is
better, it this sense Cisco and BIRD have it in natural way, while Juniper
has it inverted.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."


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