The Cisco 12000 SIP-400 is a 2.5-Gbps IP Services Engine (ISE)-based SIP that hosts SPAs used for applications that require a high level of performance, scalable physical and logical connections, and high-touch QoS and security features. It enhances and scales functions and benefits previously available on the 2.5-Gbps ISE line card, allowing carriers to offer services such voice over IP (VoIP), Multiprotocol Label Switching (MPLS) VPN, Internet access, and low-speed leased-line aggregation (DS-3, E3, Channelized T3 [CT3], n x T1, and n x DS-0).