[j-nsp] Optimizing the FIB on MX

[sthaug at nethelp.no]

Just commenting on a couple things:

> If the MX140-A from our previous example loses its Transit link it will (via BGP-PIC) immediately reroute traffic to MX140-B
> However by default MX140-B has a best path via MX140-A -so until it receives withdrawn from MX140-A it'll loop traffic back to MX140-A.
> That's why you want MX140-B to prefer it's local exit.
> 
> *not sure what was Juniper and ALU thinking when they came up with the same protocol preference for eBGP and iBGP routes, there's a ton of reasons why you always want to prefer closest AS-EXIT.

Probably the same as Cisco, when Cisco on multiple occasions have
promoted using the same administrative distance (200) for both EBGP
and IBGP as "best practice".

> Caveats:
> "vrf-table-label" must be enabled at the routing-instance on the MX140s - just another stupidity in this script kiddie OS of Junos

You are of course free to call JunOS whatever you want. Calling JunOS a
"script kiddie OS" may not the best way to be taken seriously.

In any case, vrf-table-label is *much* older than PIC (around 10 years,
if I remember correctly).

Steinar Haug, Nethelp consulting, sthaug at nethelp.no