[j-nsp] ARP resolution algorithm? Storage of MX transit packets?

[Saku Ytti]

On Thu, 31 Jan 2019 at 10:57, Gert Doering <gert at greenie.muc.de> wrote:

> I think Robert is talking about router-to-router LANs, where you have
> "prior knowledge" in your FIB.
>
> Like, OSPF neighbours, or BGP next-hops pointing to LAN adjacencies - so
> the router could go out and start the ARP process the moment it learns
> "I have a next-hop in BGP pointing to <lan interface>:<ip>".

Yeah even this is driven by traffic, you BGP wanting to send packet causes it
to be resolved.

Heck this does not cause ARP:
ip route 1.2.3.0 255.255.255.0 <far_end_link_on_ethernet>

This route gets installed and stays installed regardless if far end
will resolve or not. And far end wont be resolved until something
wants to go to far_end or wants to go to 1.2.3.0/24

Huawei VRP has magic feature to enable periodic ARP for static route,
so that static route is not installed if far_end does not resolve or
stops resolving. Cisco and Juniper do not.

-- 
  ++ytti