Good questions;
1) The idea is to prove the SUT and it's supported interface (not Juniper) has robustness when passing line rate traffic for N days. Similar the IEEE BER requirmeents there are acceptable packet error rates which is what this test is trying to prove.
So this test is removing the need for a complex topology and expensive traffic generator. Instead, it's two devices (SUT and Juniper) and a traffic storm started by the SUT.
2) At this point we have proven the SUT by itself, within it's own switching timing domain is error free, but the requirment for interoprobility testing is still outstanding. We have done this same test with Cisco and now I'm working on getting Juniper in the interop test bed as well.
Thanks in advance,