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

Saku Ytti saku at ytti.fi
Thu Jan 31 03:33:20 EST 2019

On Thu, 31 Jan 2019 at 10:26, Gert Doering <gert at greenie.muc.de> wrote:

> Can you do static ARP entries on JunOS?  You can do that on Cisco - while
> not exactly what you might have had in mind, it would be theoretically
> possible to have management system turn off ARP resolution for certain
> VLANs and put static ARP entries into the config.

I don't think you can turn it off in JunOS. So they'd have to change
code anyhow, at which point, I'd rather take translation than static

> (I had to use it in the past due to ARP and ND bugs at peering routers,
> so I know "it works for a small number of entries" - no idea if it would
> scale, or whether Cisco properly programs static ARP into HW right
> away, or just uses it for lookups when punting)

It does get programmed into HW adjacency.

And while I'm asking for things that won't happen. Give us
'point-to-point' ethernet. If you configure 'point-to-point' keyword
in interface, it'll just use all-zero MACs or some reserved MAC and
never punts for ARP. There are shops who don't have L2 aggregation
anywhere at all, and most of us don't have any of it in backbone
infra. Should be very easy change, maybe phase2, drop DMAC+SMAC
entirely, giving us 3 free MPLS label at same MTU as edge, so we dont
need overspeed to handle 1GE of edge traffic at small size.


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