The Cisco 12000/XR 12000 Series SIPs are based on Cisco IP Services Engine (ISE) technology. The Cisco 12000/XR 12000 Series SIP hosts the common SPAs used for interconnecting routers with each other or with other communication devices such as voice-over-IP (VoIP) gateways; mobile network and media gateways; Web servers; storage devices; and Frame Relay, ATM, and Ethernet Layer 2 switches. The Cisco 12000/XR 12000 Series SIP enhances and scales all functions and services previously available on the Cisco ISE 2.5-Gbps line card. Examples of these enhancements include line rate of IPv4 and IPv6 at 10 Gbps, low-speed features such as Multilink Point-to-Point Protocol (MLP) and Multilink Frame Relay (MLFR), Compressed Real-Time Protocol (cRTP), scalable multicast solution with high performance, and feature-rich QoS.