[j-nsp] port mirror to multiple ports on MX80 in inet6

[Clarke Morledge]

Paul,

It occurred to me after my last testing of the L2 port mirroring feature 
that perhaps the issue involving traffic that also hits an IRB along the 
way could be related to behaviorial differences between different versions 
of Junos and different chipsets.

In my previous tests that showed  Layer2 port mirroring only working for 
egress packets and NOT for ingress packets destined for the IRB was on the 
MX 240 platform (not MX80) with I-Chip and therefore NOT Trio.   At that 
time, I was also running 10.2.

I tried the same type of setup again with I-Chip based hardware using 
10.4R10.7 and now I can not get the layer2 port mirroring to pick up 
anything when there is an IRB involved.

However, if I do the same type of configuration using an MX-80 (Trio) I 
get the type of results you got the first time:   packets on ingress that 
hit the IRB get mirrored at layer2, but packets that egress from the IRB 
do not.  This is using 11.4R5.5.

Fortunately, using layer3 port mirroring off of the IRB does appear to 
work in all configurations/hardware that I have tested.   But it sure is 
confusing.


Clarke Morledge
College of William and Mary
Information Technology - Network Engineering
Jones Hall (Room 18)
Williamsburg VA 23187