It’s hard to improve on Kevin’s excellent but still uncertain answer to your question. He’s right to observe that Nortel certs will remain valid and valuable until there’s no more equipment in use that bears the name “Nortel” somewhere on the enclosure. And likewise, if you already have those certs they’re still worth something, but if your part-way toward earning them, it’s probably best to break off and switch to Avaya or some other still-active vendor’s cert program instead. Depending on how Avaya handles the acquisition, they may very well roll the Nortel certs into their own cert program and might even create an upgrade path for Nortel cert holders to earn equivalent level Avaya credentials on a special fast track.

But as Kevin points out, only time will tell. In the meantime, keep an eye on what Avaya is doing and take your best shot when you know where to aim.

HTH,
—Ed—