Cisco 2921 Integrated Services Router(ISR) 3 integrated 10/100/1000 Ethernet ports (RJ-45 only) 2 service module slot 4 Enhanced high-speed WAN interface card (EHWIC) slots 3 onboard digital signal processor slots 1 Internal Service Module slot for application services Fully integrated power distribution to modules supporting 802.3af Power over Ethernet (PoE) and Cisco Enhanced PoE Embedded hardware-accelerated VPN encryption for communications with Group Encrypted Transport VPN, Dynamic Multipoint VPN, or Enhanced Easy VPN Integrated threat control using Cisco IOS Firewall, Cisco IOS Zone-Based Firewall, Cisco IOS IPS, and Cisco IOS Content Filtering Voice High-density-packet voice DSP module, optimized for voice and video support Standards-certified VoiceXML browser services Cisco Unified Border Element capabilities Cisco Unity Express voicemail support Support for Cisco Communications Manager Express and Survivable Remote Site Telephony Modularity Features and Benefits.