On Wed, Sep 30, 2009 at 5:34 PM, Les Mikesell lesmikesell@gmail.com wrote:
But even with old-school phone switches, your support contract would require software updates at regular intervals and unless you had redundant hot-failover equipment, that would involve scheduled downtime.
Not with Nortel. Patches were optional -- updates, new features and additional licenses were sold as separate products. That's in the PBX (Option) line of switches (almost all of which have been "dual core" -- redundant -- for about 25 years). In the Key System switches (Norstar), patches were unavailable, though you could buy keycodes to enable additional features. If you wanted to update you bought a new version of the software on a flash medium (if one was available).
Traditional telephone switches are expected to up 24/7 unless you are doing a major upgrade -- and that's usually scheduled months in advance. The goal is to achieve the "five 9s" (99.999% up time).