Knowledge of ATM circuit types and virtual circuit mapping is absolutely critical to designing and maintaining a DSL network. The single most common cause of network connectivity issues in the DSL network is also the most easily understood: failure to design and adhere to a good virtual circuit-mapping plan.
Although the ATM Forum defines several connection types that are all theoretically applicable to DSL, the current world of DSL makes common use of only three:
Permanent virtual circuit (PVC)
Permanent virtual path (PVP)
ATM virtual circuits are identified by the virtual path and virtual channel. A virtual path contains multiple virtual channels, like a large bundle of smaller pipes. Each individual ...