Hello Magnus,
I would also prefer the old behaviour was retained as default, and that a
configuration knob was provided to enable the new behaviour.
My arguments to Juniper would be:
- It should be a low-cost effort to make the code change so that TWO
timers are kept, as the code already exists. Increased RAM utilisation ought to
be slight.
- It should be fairly trivial to include a configuration knob to select
the behaviour you want; ideally the default is the old behaviour, but either
way achieves the same goal.
- BGP route age timer should reflect changes in the eBGP route
advertisement, because:
- Changes in your internal network which affect BGP route
selection or next hop interface are a holistic function of your router's
internal routing.
- The BGP route's age is, intuitively, the age since the route
was received from the eBGP speaker, ie: RIB-In, not inet.0 (or whichever table).
- Why not give the best of both? Retain two route age timers and
display both in the CLI.
We haven't found this change in behaviour to adversely affect us in GEANT, but
have the view that having both timers would be ideal.
Best regards,
Niall
Niall Donaghy
Senior Network Engineer
GÉANT
T: +44 (0)1223 371393
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-----Original Message-----
From: juniper-nsp [mailto:juniper-nsp-boun...@puck.nether.net] On Behalf Of
Magnus Bergroth
Sent: 26 January 2018 11:45
To: juniper-nsp <juniper-nsp@puck.nether.net>
Subject: [j-nsp] Juniper route age reset behavior
Hi
We have seen a change in how junos handles age in command "show route".
In Junos 15.1R bgp routes age told you how long the route had been present in
the routing table. If you have a dual homed customer bgp age timer showed how
long time ago the customer advertised the route. Very practical to see how
stable the customer connection has been.
In 15.F and new releases this has been changed so that any change to the route
will reset the age time. If a route goes from inactive to active "route age"
gets reset. If your igp changes so the outgoing interface changes the "route
age" gets reset.
We been trying to get juniper to change back the behavior but Juniper
engineering thinks it's now working as it should.
We haven't been able to find any RFC the describes route age. The only argument
towards Juniper that we have is that they are changing default behavior.
Are there any one else that has seen this new "route age" behavior and have any
open cases with Juniper, or have any good argument that we can throw at Juniper?
Kindly
Magnus Bergroth
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