The Cisco 4000 series routers are highly cost-effective, modular platforms that reduce network costs and complexity by aggregating multiple LANs into a single multiprotocol network. Cisco 4000 series routers offer increased security through packet filtering between LANs and provide the bandwidth reservation features and performance required for advanced applications such as LAN-to-Asynchronous Transfer Mode (ATM) access, IBM data-link switching (DLSw), Advanced Peer-to-Peer Networking (APPN), and videoconferencing. This series of routers provides regional offices with a broad range of capabilities and features. It offers flash memory that stores the powerful Cisco Internetwork Operating System (Cisco IOS) software and slots for optional network processor modules (NPMs) - individual removable cards used for external network connections including Ethernet, Token Ring, Fast Ethernet, ATM, Fiber Distributed Data Interface (FDDI), High-Speed Serial Interface (HSSI), Integrated Services Digital Network (ISDN), Basic Rate Interface (BRI) and Primary Rate Interface (PRI), E1/T1 serial, and high-density, low-speed serial.The Cisco 4500-M is a midrange router with a 100-MHz reduced instruction set (RISC) CPU for supporting high-density/low-speed or mid-density/high-speed LAN and WAN connectivity.