What type of protocol is the Provider Backbone Bridging (PBB)?

Provider Backbone Bridging (PBB) is classified as a packet transport protocol designed to enhance the scalability and performance of Ethernet networks. One of its main purposes is to facilitate the delivery of Ethernet frames over a wide-area network (WAN) while maintaining the integrity and organization of multiple virtual local area networks (VLANs). PBB achieves this by encapsulating Ethernet frames and adding a new header that includes information necessary for proper routing and processing by the network infrastructure.

This protocol enables service providers to effectively manage and engineer data paths within their networks. By using PBB, service providers can achieve efficient data transport, allowing for better management of network resources and improved performance. The encapsulation allows for a more structured approach to how data is sent and received, which ultimately leads to enhanced networking capabilities.

In contrast, options related to increasing latency, application-level protocol for security, or transport-layer protocol for data compression do not accurately describe the primary function and purpose of PBB as a packet transport protocol.