Long before AT&T Inc. signed its $67 billion deal to buy BellSouth Corp., telecommunications industry analysts and executives were predicting a sweeping round of consolidation among networking equipment makers as their carrier customers themselves merged.

For the most part, that shakeout has yet to materialize. But experts say AT&T’s blockbuster purchase may be just the kind of catalyst to finally drive telecom gear makers together as they seek to “scale up” to meet the needs of a shrinking roster of premium corporate clients.