Cisco 2921 Integrated Services Router (ISR Generation 2) Full Product Description

1. Short Overview

Naming & Variant Breakdown

• CISCO2921/K9: Standard AC-powered base router with universal IOS image and embedded K9 AES/3DES crypto hardware
• CISCO2921-SEC/K9: Pre-bundled Security variant with Zone-Based Firewall, IOS IPS, full IPsec/SSL/DMVPN enabled
• CISCO2921-V/K9: Unified Communications bundle pre-licensed for CME/SRST embedded voice call processing
• CISCO2921-VSEC/K9: All-in-one Voice + Security integrated branch bundle
• CISCO2921-AX/K9: Advanced services bundle supporting SRE virtualization, WAAS wide-area optimization
• CISCO2921-AC-IP/K9: AC PoE power supply variant delivering high-budget inline power for IP phones via switch EHWICs
• CISCO2921-DC/K9: 24–60V DC autoranging telecom-grade power model for central office cabinet deployments
• -HSEC+/K9: High-security enhanced bundle optimized for massive concurrent IPsec tunnels

Core Differentiators vs Cisco 2911

1. 3 onboard PVDM3 DSP slots(only 2 on 2911) to support far more concurrent VoIP calls, wideband audio, and multi-party conferencingCisco
2. Built-in shared SFP fiber slot alongside 3 GE RJ45 ports (2911 has no native SFP slot) for fiber WAN/LAN uplinks
3. Higher multi-service throughput up to 130 Mbps aggregate vs 100 Mbps on the 2911
4. Larger chassis power budget supporting fully loaded high-density EHWIC, ISM, and triple PVDM modules
5. Identical core expansion layout: 4 EHWIC universal slots, 1 ISM internal service module slot, dual USB 2.0 ports, single external CompactFlash slot, RPS redundant power support, DC power option
6. Same multi-core CPU architecture, max 2GB DDR2 ECC DRAM, max 8GB CompactFlash storage ceiling

2. Hardware Interface & Physical Specifications

Modular Expansion Architecture

1. 4 × Rear Universal EHWIC (Enhanced High-Speed WAN Interface Card) slots
   Each slot supports single-wide EHWIC, double-wide EHWIC-D, legacy HWIC, WIC, VIC, VWIC voice cards; two slots accept double-wide high-bandwidth EHWIC-D modules:
   • EHWIC: ADSL2+, VDSL2, G.SHDSL, synchronous serial, 4-port GE switch, cellular 3G/4G wireless WAN cards
   • WIC: ISDN BRI, synchronous/asynchronous serial, analog modem WICs for dial-on-demand backup links
   • VIC/VWIC: FXS/FXO/E&M analog station/trunk cards, fractional T1/E1 multi-flex voice trunks
2. 1 × ISM (Internal Service Module) internal slot
   Replaces the legacy AIM slot from ISR 1 generation; supports SRE (Services Ready Engine) virtualization modules, WAAS wide-area bandwidth optimization, CUE voice mail storage, and embedded application services to offload CPU-intensive tasks without occupying external EHWIC slotsCisco.
3. 3 × Motherboard PVDM3 DSP slots (Exclusive upgrade over 2911)
   Host Packet Voice Digital Signal Processor modules to handle VoIP codecs, wideband G.722 audio, 128ms G.168 echo cancellation, T.38 fax relay, and multi-party audio conferencing without consuming external expansion slots; triple DSP capacity enables large-scale IP phone deploymentsCisco.

Fixed Built-in Rear Panel Ports

1. 3 × Auto-MDI-X 10/100/1000BASE-T Gigabit Ethernet (GE0/0, GE0/1, GE0/2) + 1 shared SFP mini-GBIC slot
   The SFP port shares hardware with GE0/0; using SFP disables the corresponding RJ45 port. All Gigabit ports fully support IEEE 802.1Q VLAN trunking, inter-VLAN routing, LACP link aggregation to isolate corporate, finance, engineering, guest, and sensitive POS payment subnets.
2. RJ45 Serial Console port (115.2 kbps max baud) – local out-of-band CLI management
3. Mini-USB Type-B Console port – secondary lightweight local management
4. RJ45 AUX port – remote emergency access via external PSTN analog modem
5. 2 × USB 2.0 Type-A ports– high-speed offline config/log backup storage, two-factor crypto authentication tokens
6. Removable external CompactFlash (CF) slot – primary persistent storage for IOS universal images, full running configurations, persistent event logging
7. Power inlet: Standard IEC AC socket (DC variant uses 24–60V negative terminal block telecom input)
8. Dedicated RPS redundant power supply connector for fault-tolerant mission-critical branch deployments
9. Chassis ground lug + Kensington anti-theft lock slot for physical rack security

Memory & Performance Benchmarks

• Processor: Multi-core PowerQUICC RISC CPU with dedicated embedded hardware crypto FPGA acceleration
• Default DRAM: 512MB DDR2 ECC SDRAM; maximum expandable DRAM: 2048MB (2GB) via dual DIMM slots
• Default Flash memory: 256MB CompactFlash; maximum supported Flash: 8GB CF card
• Multi-service mixed voice/data/security throughput: Up to 130 Mbps aggregate wire-speed performance
• Hardware crypto acceleration: Native AES-256, 3DES, DES IPsec, SSL/TLS, GRE VPN offloading; no mandatory external acceleration modules required
• Maximum concurrent site-to-site IPsec tunnels: Up to 300+, scalable with full 2GB DRAM and ISM security modules
• Supported IOS releases: Cisco IOS 15.0(1)M through 15.7(3)M universal multi-service maintenance images; feature functions unlocked via permanent chassis-bound software licenses (SL-29-DATA-K9, SL-29-SEC-K9, SL-29-UC-K9)
• Voice capacity: Triple PVDM3 DSP modules support up to 144 concurrent VoIP calls; Cisco CME embedded call processing for up to 200 IP phones, SRST survivable remote branch telephony, Unity Express voice mail hosted via ISM-CUE storage modules

Physical & Power Parameters

• Form factor: 2U standard 19-inch rack-mount metal chassis with integrated rack ears
• Standard AC power supply: 100–240V 50/60Hz universal autoranging internal power supply (hot-swappable with external RPS support)
• DC variant (C2921-DC): 24–60V autoranging negative DC telecom input for central office cabinet deployments
• PoE variant (C2921-AC-IP): Integrated inline power distribution delivering up to 200W PoE budget, expandable to 750W with PoE boost accessoryCisco
• Typical chassis power consumption: ~240W under fully loaded EHWIC/PVDM/ISM module configuration
• Front panel status LEDs: System power, fault alarm, CompactFlash activity, dual USB port status, PVDM/ISM health indicators, four EHWIC slot link/activity, three Gigabit Ethernet + SFP link/activity
• Operating environment
  • Operating temperature: 0°C to +40°C below 1800m altitude; 0°C to +25°C above 1800m up to 3000m
  • Relative humidity: 5–85% RH non-condensing
• Dimensions (H × W × D): 8.9 × 44.5 × 30.5 cm (3.5 × 17.25 × 12 inches)
• Fully loaded weight: ~10.5 kg (23.1 lbs) with complete expansion modules
• No native chassis PoE output except for dedicated -AC-IP power supply variant.

3. Cisco IOS Universal Image Multiservice Feature Suite

Core Routing & Multi-WAN Connectivity

• Full dual-stack IPv4 / IPv6 routing suite: Static routes, RIP v1/v2, OSPF, EIGRP, BGP, IS-IS, PIM multicast suite, BFD bidirectional forwarding detection
• WAN encapsulation support: PPP, HDLC, Frame Relay, ATM, ISDN, PPPoE/PPPoA for DSL, Dial-on-Demand Routing (DDR) for automatic backup failover, MPLS L2/L3 VPN, GETVPN
• HSRP/VRRP for router high availability redundancy; NHRP DMVPN hub-spoke multi-site overlay VPN architecture
• NAT services: Static NAT, dynamic NAT, PAT overloading, multi-address NAT pools, NAT64 IPv4-IPv6 transition support
• Dual VLAN trunking standards support: IEEE 802.1Q for inter-VLAN routing across three onboard Gigabit Ethernet ports and SFP fiber uplinks.

Unified Communications Voice & Fax Integration (Key High-Density Voice Differentiator)

1. VoIP signaling protocols: H.323, SIP, MGCP, SCCP native support for large-scale Cisco Unified IP Phone deployments
2. Analog/digital telephony via VIC/VWIC + triple PVDM3 DSPs: FXS station ports, FXO PSTN trunk lines, E&M PBX tie connections, fractional T1/E1 multi-flex voice trunks
3. T.38 real-time fax relay over IP, fax passthrough, store-and-forward fax routing
4. DSP-accelerated voice codecs: G.711, G.729a, G.726, wideband G.722 high-fidelity audio, video conferencing codec support
5. Enterprise telephony tools: Scalable multi-site dial plans, voice hunt groups, toll bypass to eliminate expensive long-distance PSTN charges
6. CME embedded call manager, SRST survivable remote telephony, Unity Express voice mail/auto-attendant hosted via ISM-CUE storage modules.

Enterprise QoS & WAN Optimization

• Base QoS tools: Weighted Fair Queuing (WFQ), CBWFQ, per-interface traffic shaping
• Advanced QoS (Data/UC license): Low Latency Queuing (LLQ), Frame Relay Traffic Shaping (FRTS), WRED congestion avoidance, DSCP/802.1p traffic marking
• Link Fragmentation and Interleaving (LFI), cRTP VoIP header compression to eliminate voice jitter over low-speed DSL/ISDN backup links
• NBAR2 next-generation deep packet inspection for application-aware traffic prioritization of business-critical software; ISM WAAS module for end-to-end WAN bandwidth optimization.

Integrated Self-Defending Network Security Suite

1. Zone-Based Stateful Firewall (ZBFW): Deep application-layer inspection for HTTP, FTP, SIP, H.323 and all mainstream enterprise business protocols
2. IOS IPS inline signature-based intrusion prevention with real-time threat detection and automated connection blocking
3. Embedded hardware-accelerated VPN stack:
   • AES-256/3DES/DES IPsec site-to-site branch tunnels
   • Cisco Easy VPN Remote centralized security policy provisioning for remote branch locations
   • DMVPN scalable hub-spoke multi-site overlay networks
   • SSL VPN for browser-only remote worker access without client software
4. AAA security framework: PAP/CHAP authentication, RADIUS/TACACS+ centralized access control and complete audit logging
5. Standard/extended ACLs, dynamic ACLs, anti-DDoS traffic policing, security zone segmentation to isolate sensitive POS payment and finance subnets.

Management, Automation & Operations

• Triple out-of-band management interfaces: RJ45 Serial Console, Mini-USB Console, and AUX modem port for emergency offline IT maintenance
• Secure remote management: SSHv2, HTTPS, SNMP v1/v2c/v3, TR-069 automated remote provisioning
• Graphical configuration utility: Cisco Configuration Professional (CCP) for simplified zero-touch mass branch deployment
• AutoInstall automated remote IOS image and configuration download over WAN links for nationwide branch rollouts
• Removable CompactFlash storage for easy IOS upgrades, configuration backup, and centralized log archiving
• Persistent syslog event logging, NTP time synchronization for consistent audit log timestamps
• Dual USB 2.0 ports for offline config storage and two-factor authentication security tokens
• Cisco EnergyWise power management for intelligent energy consumption control of attached network devices.

4. Typical Deployment Scenarios

1. Large regional enterprise headquarters multi-service edge gateway: Multiple aggregated T1/E1 PRI trunks via high-density VWIC EHWIC, dual fiber Metro Ethernet primary/secondary WAN uplinks via SFP slot, VDSL2 EHWIC copper backup link, triple PVDM3 DSP modules supporting over 120 concurrent VoIP calls, three Gigabit Ethernet ports to segregate finance, engineering, staff, and guest VLANs, ISM SRE virtualization module for local application hosting, high-volume DMVPN IPsec tunnels to corporate headquarters, integrated ZBFW/IPS security stack for enterprise compliance.
2. National multi-chain retail flagship voice gateway: ADSL2+ EHWIC primary broadband WAN, ISDN BRI WIC dial backup, CME embedded call processing for 150–200 on-site IP phones, ISM-CUE voice mail storage module, PCI DSS compliant zone firewall for payment network isolation, embedded hardware encryption for hundreds of store site-to-site VPN connectivity.
3. Global mixed POTS/ISDN DSL carrier managed high-capacity business CPE: Universal dual-standard DSL EHWIC copper broadband access, DC power variant for central office rack deployment, ISM WAAS optimization module for tenant bandwidth control, DMVPN overlay to carrier central service hub, integrated firewall/IPS for tenant threat isolation and network segmentation.
4. Advanced enterprise networking training lab core router: Universal EHWIC/WIC/VIC modularity to teach fiber SFP uplinks, high-density T1/E1 PRI voice trunking, triple Gigabit multi-VLAN inter-routing, hardware-accelerated high-volume IPsec VPN, and full unified communications gateway labs; expanded 2GB DRAM and large CF capacity fully support feature-rich IOS 15.x M images unavailable on entry-level 2901/2911 routers.

5. Standard Package Contents of CISCO2921 / 2921-DC / 2921-AC-IP

Separately Sold Optional Accessories

• EHWIC/WIC/VIC/VWIC WAN and analog/digital voice interface cards
• PVDM3 DSP voice compression modules for VoIP, wideband audio and T.38 fax relay
• ISM Internal Service Modules: SRE virtualization, WAAS wide-area optimization, CUE voice mail storage
• DRAM memory expansion DIMMs (512MB / 1GB / 2GB)
• CompactFlash memory upgrades (256MB / 1GB / 4GB / 8GB)
• CAT5e/CAT6 Gigabit Ethernet patch cords, RJ11 DSL/ISDN telephone line cables
• External PoE injectors for non-PoE IP cameras and wireless access points
• External redundant power supply units (RPS) for high-availability branch deployments

Software Licensing Information

1. SL-29-DATA-K9: Base routing, IPv6, MPLS, advanced QoS, NBAR2 application classification
2. SL-29-SEC-K9: Zone-based firewall, IOS IPS, full IPsec/SSL/DMVPN encryption, advanced threat mitigation
3. SL-29-UC-K9: CME/SRST embedded voice call processing, Unity Express voice mail, full VoIP codec support
   Embedded K9 crypto hardware complies with US ITAR export regulations for global shipments. All licenses are permanent with no recurring subscription fees.

Short Commercial Catalog Summary