Cisco 1721 Full Product Description

1. Short Overview

Naming & Suffix Context

• 1721: Upgraded dual-WIC slot base router in the 1700 lineup; its direct predecessor is the Cisco 1720, with key hardware and feature upgrades.

Core Differentiators vs Cisco 1720

1. Native IEEE 802.1Q VLAN trunking and inter-VLAN routing (absent on the 1720)Cisco
2. Larger memory ceiling: Max 96MB DRAM / 16MB Flash vs 48MB DRAM / 16MB Flash on the 1720Cisco
3. Higher packet forwarding throughput: 12,000 pps vs 8,400 pps on the 1720Cisco
4. Built-in internal slot for optional VPN acceleration module (MOD1700-VPN) to offload IPsec crypto processingCisco
5. Higher base default memory: 32MB DRAM / 16MB Flash (1720 ships with 32MB DRAM / 8MB Flash)Cisco
6. Improved Motorola MPC860P 50MHz RISC processor for faster encryption and routing workloadsCisco

2. Hardware Interface & Performance Specifications

Modular WAN Expansion

• 2 × WIC (WAN Interface Card) slots: Interchangeable WICs support diverse global WAN media, fully cross-compatible with older Cisco router families to reduce spare inventory:
  • ISDN BRI (WIC-1B-S/T) for dial backup
  • T1/FT1, 56k serial integrated DSU/CSU
  • Synchronous/asynchronous serial leased lines
  • ADSL / G.SHDSL / G.FAST DSL WICs for copper broadband
  • Dual-port serial WICs for multi-line deployments
• 1 internal hardware acceleration slot: Accepts MOD1700-VPN VPN accelerator module for hardware-offloaded IPsec DES/3DES encryption up to T1 line speedsCisco

Fixed Built-in Ports

1. 1 × 10/100BASE-TX autosensing Fast Ethernet LAN port (RJ45): Auto-negotiates 10/100 Mbps full/half duplex, supports IEEE 802.1Q VLAN tagging for multi-VLAN internal segmentation
2. 1 × RJ45 Console port (blue): Local out-of-band CLI management, up to 115.2 kbps baud rate
3. 1 × RJ45 AUX port (black): Remote out-of-band management via external analog modem, up to 115.2 kbps asynchronous speed
4. Kensington security lock slot for physical desktop anti-theft protectionCisco

Memory & Performance Benchmarks

• Default DRAM: 32MB; maximum expandable DRAM: 96MB
• Default Flash memory: 16MB; maximum supported Flash: 16MB (dual-bank Flash for primary/backup IOS image redundancy)Cisco
• Packet forwarding throughput: Up to 12,000 pps
• Maximum concurrent IPsec site-to-site VPN tunnels: Up to 100 (varies by IOS feature set and memory configuration)
• Supported IOS releases: Primarily IOS 12.0, 12.1, 12.2 XM maintenance trains (last official supported firmware versions)Cisco

Physical & Power Parameters

• Form factor: Fanless compact metal desktop chassis; optional third-party 19-inch rack-mount brackets available
• Power input: External 12V DC wall-mount AC-DC power adapter (not included base unit)
• Front panel LEDs: System power, WIC slot status, Fast Ethernet link/activity, crypto module status
• Operating environment: Dry indoor office use only; operating temperature 0°C to +40°C, non-condensing relative humidity 10–85% RH
• No native PoE power output; all PoE endpoints require external PoE injectors

3. Cisco IOS Software Feature Set

Routing & WAN Connectivity

• IPv4 routing protocols: Static routes, RIP v1/v2, OSPF, EIGRP, BGP (IP Plus feature set)
• WAN encapsulations: PPP, HDLC, Frame Relay, ISDN, PPPoE for DSL, Dial-on-Demand Routing (DDR) for redundant backup links
• HSRP for router redundancy; NHRP for DMVPN hub-spoke multi-site VPN architectures
• Network Address Translation (NAT): Static NAT, dynamic NAT, PAT overloading for multi-user Internet access
• IEEE 802.1Q VLAN trunking and inter-VLAN routing for segmented internal office LANsCisco

QoS & Unified Communications

• Base QoS: Weighted Fair Queuing (WFQ), traffic shaping
• Advanced QoS (IP Plus): Low Latency Queuing (LLQ), Frame Relay Traffic Shaping (FRTS), WRED, DiffServ DSCP marking, Link Fragmentation and Interleaving (LFI) for VoIP over low-speed WANs
• VoIP support: H.323, SIP, RSVP bandwidth reservation for branch voice telephony

Integrated Enterprise Security Suite

1. IOS Context-Based Access Control (CBAC) stateful firewall: Dynamic deep packet inspection, application-layer filtering
2. Optional IOS signature-based IDS for intrusion threat detection and mitigation
3. Full VPN stack:
   • Hardware-accelerated IPsec (DES / 3DES) site-to-site branch tunnels (with MOD1700-VPN module)
   • L2TP, L2F remote user VPN
   • Cisco Easy VPN Remote: Centralized policy pull from headquarters VPN headends to simplify remote branch provisioning
4. AAA authentication: PAP/CHAP, RADIUS, TACACS+ for user access audit and control
5. Standard/extended ACLs for traffic filtering and access restriction

Management & Operations

• CLI command-line management via Console/AUX ports
• SNMP v1/v2c for network monitoring, RMON traffic statistics
• Cisco ConfigMaker graphical tool for simplified zero-touch deployment
• AutoInstall: Automated remote configuration download over WAN links
• Dual Flash bank storage for primary and backup IOS image disaster recovery
• Syslog event logging, NTP time synchronization for audit log consistency

4. Typical Deployment Scenarios

1. Small retail branch office: Combo Ethernet primary fiber WAN, ISDN BRI WIC dial backup, 802.1Q VLAN segmentation to isolate POS payment terminals from employee LAN, IPsec site-to-site VPN to corporate HQ, integrated firewall for PCI compliance security
2. Remote rural SME office: ADSL WIC broadband primary access, analog modem AUX port out-of-band management, LLQ QoS prioritization for office VoIP phones, Easy VPN for remote employee L2TP access
3. Small regional enterprise edge router: Dual serial T1 WIC redundant leased-line WANs, hardware VPN accelerator for multiple concurrent site-to-site tunnels, multi-VLAN routing for separate finance, HR, and engineering office subnets
4. Legacy DSL carrier customer premise equipment: G.SHDSL WIC copper access, NAT for multi-user Internet sharing, CBAC firewall protection against external Internet threats

5. Standard Package Contents of C1721

Separately Sold Optional Accessories

• 12V DC external universal AC power adapter
• WAN Interface Cards (WIC-1B-S/T, WIC-T1-DSU, WIC-ADSL, WIC-2SERIAL, etc.)
• MOD1700-VPN hardware IPsec encryption accelerator module
• CAT5e RJ45 Ethernet patch cords
• RJ11 DSL/ISDN telephone line cables
• CAT4/CAT6 USB LTE dongles for secondary wireless backup
• USB flash drives for offline config storage
• Third-party 19-inch rack-mount bracket kit
• External PoE injectors for IP cameras and wireless access points

Software Licensing Information

Short Commercial Catalog Summary