As an alternative of the Shared Backup Path Protection (SBPP) method, we develop a framework for dynamic provisioning of survivable services based on the use of p-cycles to form a Protected Working Capacity Envelope (PWCE) within which dynamic provisioning of protected services is greatly simplified. Based on p-cycles, the restoration speed of rings is obtained, but with the capacity efficiency of shared-mesh networks. In addition, with PWCE, arbitrarily fast dynamic service demands can be handled with much less complexity (in terms of database dependency and state update dissemination) than under SBPP. Only a simple OSPF-topology view of non-exhausted spans in the envelope is required. If a new path can be routed through the envelope, it is protected by virtue of being routable. This is in contrast to needing a full database of network state so that the end-user can set up a shared backup protection path under SBPP. In addition, dissemination of state updates occurs only on the time-scale of the non-stationary evolution of the demand statistics, not on the time-scale of individual connections. During statistically stationary periods, there is no dissemination of state updates whatsoever with an envelope that is well matched to its load. The PWCE concept thus offers some new tradeoffs between operational simplicity and spare capacity efficiency. The main contribution of this work is the detailed implementation and simulation of test networks operating under PWCE and designed with novel envelope volume maximizing formulations.