There is increasing demand for higher speed service by subscribers served by DSLAMs where the total bandwidth demand has not justified running fiber, and a need to deploy a larger number of smaller DSLAMs closer to customers so that xDSL performance can be enhanced.  

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Service operators facing these challenges and universal service mandates have to satisfy this demand while containing cost if they are to ensure profitability.  NxT1/E1 backhaul cannot scale very cost effectively.  And running fiber can be extremely expensive unless the DSLAM is large enough to present significant demand, and is reasonably close to a CO.

More cost effective and scalable backhaul is required for these kinds of situations.