System integrity involves ensuring the integrity of network element systems and providing an acceptable level of service. Exploitation of vulnerabilities associated with system integrity may result in service denial or disruption, or the unauthorized modification of user or network information and network services.
The unbundling of services increases the real-time processing requirements and therefore services provided as a result of ONA requirements will require more real-time processing [10]. The paper ``ONA: Demands on Provisioning and Performance'' notes that the evolution of the public network to support enhanced services creates the need for planning the growth of real-time switch capacity in concert with the emergence of these new services. If carriers do not adequately plan for increased real-time switch capacity, the PSN is vulnerable to disruption and denial of service problems.