[j-nsp] MX loopback filter and monitor traffic

[Alex]

> If all of the traffic that comes into the router to the RE via these 
> exposed Layer3 interfaces eventually makes it way to the RE via the 
> loopback address, at unit 0, why is that the "monitor traffic" command 
> does not show me anything?    Why is the loopback interface so "special"?

JUNOS lo0 is not the same as CSCO Loopback[0-9][0-9]* (note 
lowercase/uppercase L and numbers).
In JUNOS, the traffic is never looped back via lo0 unlike in IOS 
Loopback[0-9][0-9]*.
Therefore, it is not possible to:
1/ use "monitor traffic interface" on JUNOS lo0
2/ use NAT-on-a-stick with JUNOS lo0
3/ loop the VoIP call thru JUNOS lo0 in Cisco IOS dial-peer style
4/ use FBF for traffic originated from the RE itself

HTH
regards
Alex