Mitch and Steve (who sent me a private note),
Thanks for the notes and apologies for the delayed response. In
general, we are very sensitive to minimizing downtime, which is why we
scheduled the Phase-5 deployment steps to be implemented at a time
where usage is generally very low.
It turns out that for each CNSS the Phase-5 upgrade divides into two
natural sections: the intra-CNSS upgrade and the ENSS-CNSS links.
Both E133 and E134 have T1 backup links to previously upgraded CNSS's
which protect them during the Hartford intra-CNSS section.
The T1 backups are not going to help while the ENSS-CNSS section is
underway, however, so we will try to stagger HTF/E133/E134 and
WTN/E136 as much as possible. We'll work on the details following the
completion of Step 4 on 12/4 as we need to discuss this with the other
peers at HTF/WTN as well.