Phase 5 Status

Ittai Hershman ittai at
Thu Nov 25 02:37:33 UTC 1993

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.

    Hi there,
            Sorry if I've missed some details about these upgrades,
    but I'm concerned that the upgrades scheduled for the same evening
    don't all happen at once.  In particular, those scheduled for 12/18
    involve taking both E133 and E136 down.  If both are down at the
    same time, the NSFNet would lose connectivity to PSINet.  If the
    down times are already scheduled to be staggered, please let us
    know when each will be down.  If they are not already so scheduled,
    can they be?

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