There are multiple network controller software modules (for example, MPLS, PNNI) that talk with the platform software via the VSI (Virtual Switch interface) protocol to deal with their respective network topology routing and signaling. Every connection added will take away from the edge concentrator's pool of limited resources (for example, total number of connections, bandwidth, or connection IDs). The resources that these controllers vie for include:
card-level resources-number of connections.
Port-level resources-connection identifiers (for example, DLCI, VPI, VCI, etc.) and bandwidth.