Stability is not their forte
We use Avaya's telephony in our call center and I have worked with their systems for more than 10 years. Their platform is expensive but extremely solid, I just wish that they could find some other method than "Chapter 11ing" . It makes us panic every time..
When I began using their system they were called "Lucent".... and we still have a couple of Lucent cabinets stuck on our walls, we never removed them after they were decommissioned.. probably because it will leave a big white patch on the wall, :-). I prefer that G450s that we use today...