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When a customer upgrades from a lower speed tier to a higher speed one of two things happen.
1. They are reprovisioned as a MaxSync customer. An Ultra customer that upgraded to a MaxSync profile would have their provisioning rate change from 1472/256 to the highest rate the line could handle (up to 8128/512)
2. They are reprovisioned at the specific higher speed. An Ultra customer that upgraded to Extreme 3.0 would have their provisioning rate change from 1472/256 to 3008/384 (or 3552/384).

The bad news
Generally, higher bandwidth lowers the overall signal to noise margin and increases line attenuation. Changing to a higher provisioning rate or a MaxSync profile could create problems for a customer that were never an issue before. The example below shows what could happen to acustomer that upgrades from Ultra to Extreme 6.0:

Ultra (1472/256) service with traditional provisioning at the DSLAM
- Marginal line with attainable line rate of 3600/500
- Signal to noise margin of 10dB
- Line attenuation of 55dB
- Loop Capacity is about 41%
The customer has never had any problems even though the line is marginal because of the low synch rate.

Same 1472/256 service set to Extreme 6.0 (MaxSync) profile
- Marginal line attainable line rate of 3600/500
- MaxSynch rate of 3552/384 (possibly with interleaving)
- Signal to noise margin of 6dB
- Line attenuation of 60dB
- Loop Capacity is almost 100%
The customer may now experience connectivity issues and may have also been placed on interleaved profile. Although newer interleaving techniques have reduced the overall latency as compared to older methods, it still introduces some latency.

Important Information:
Due to differences in network topology, MaxSync is not available to all FastAccess customers. A simple way to tell if you are on MaxSync is to check your synch rate and modem stats. If your synch rate is far above your actual service plan, chances are you are on MaxSync.

Ultra-Mega Important Information:
Just because you have been put on a MaxSync profile does not mean you are automatically eligible for all tiers of service!

Additional Information:
How do I check modem statistics? What do the numbers mean and are my stats good?
What is Interleaving and Fastpath?

Andy Houtz DSL

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last modified: 2009-03-04 09:50:50