Cisco 1720 Full Product Description
1. Short Overview
Released in October 1998, theCisco 1720is a modular fixed-access VPN router belonging to the Cisco 1700 Series modular access router family, designed exclusively for small-to-medium businesses (SMBs) and small remote branch offices of large enterprisesCisco News.... It delivers integrated routing, multi-WAN modular connectivity, embedded Cisco IOS security (stateful firewall, IDS, and IPsec VPN), and basic QoS capabilities in a compact, fanless desktop chassis. Built on shared WIC hardware compatibility with Cisco 1600, 2600, and 3600 series routers, it provides flexible legacy and broadband WAN access without costly hardware overhauls, consolidating router, firewall, and VPN gateway functions into a single unit to cut deployment and management overhead. This platform reached end-of-sale (EoS) and end-of-life (EoL) long ago and is considered legacy hardware, superseded by later ISR generations including the 1800, 1900, and modern 1000 Series ISRs.
Key Suffix & Naming Context
-
1720: Base two-WIC slot modular router in the 1700 line; the upgraded sibling model is the Cisco 1721, which offers higher DRAM/Flash, faster forwarding performance, and native 802.1Q inter-VLAN routing (a feature the 1720 lacks).
Core Differentiators vs Cisco 1721
-
No IEEE 802.1Q VLAN routing support on the 1720 (only available on the 1721)
-
Lower maximum memory: 48MB DRAM / 16MB Flash max vs 96MB DRAM / 16MB Flash on the 1721Cisco
-
Lower IP packet forwarding throughput (8,400 pps vs 12,000 pps for the 1721)Cisco
-
Identical physical port layout and WIC slot count (2 WIC slots)
-
Same shared WIC card compatibility across both models
2. Hardware Interfaces & Physical Specifications
WAN Modular Expansion
-
2 × WIC (WAN Interface Card) slots: Accept interchangeable WICs for flexible WAN media, including:
-
ISDN BRI (WIC-1B-S/T) for dial backup
-
T1/FT1 DSU/CSU, 56k serial DSU/CSU
-
High-speed synchronous/asynchronous serial
-
ADSL/G.SHDSL DSL WICs for broadband access
-
Dual-serial WICs for multi-line leased-line deployments
-
WICs are cross-compatible with Cisco 1600, 2600, and 3600 series routers to reduce spare inventory costs
Fixed Built-in Ports
-
1 × 10/100BASE-TX autosensing Fast Ethernet LAN port (RJ45): Auto-negotiates 10/100 Mbps, full/half duplex for local office LAN connection; no integrated on-board switch (unlike higher-end 1700 variants)Cisco
-
1 × Console port (RJ45, blue): Local CLI management via terminal emulator, up to 115.2 kbps baud rate
-
1 × AUX port (RJ45, black): Remote out-of-band management via external analog modem, up to 115.2 kbps
-
Kensington lock slot: Physical security anchor for desktop deployments
Memory & Performance Benchmarks
-
Default DRAM: 32MB; maximum supported DRAM: 48MB
-
Default Flash memory: 8MB; maximum supported Flash: 16MB (dual-bank Flash for IOS backup redundancy)Cisco
-
IP forwarding throughput: Up to 8,400 packets per second (pps)
-
Maximum concurrent IPsec VPN tunnels: Up to 100 (varies by IOS feature set and memory configuration)
-
Supported Cisco IOS versions: Primarily IOS 12.0, 12.1, 12.2 XM train (last official maintenance releases)Cisco
Physical & Power Characteristics
-
Form factor: Compact fanless desktop metal chassis (no rackmount kit factory standard; optional third-party rack brackets available)
-
Power supply: External DC wall adapter (12V DC input)
-
LED indicators: System power, WIC slot status, Fast Ethernet link/activity, VPN crypto status
-
Operating environment: Dry indoor office use only; operating temperature range 0°C to +40°C, non-condensing humidity 10–85% RH
-
No internal PoE power support; all PoE devices require external injectors
3. Supported Cisco IOS Software Feature Capabilities
Routing & WAN Connectivity
-
IPv4 core routing protocols: Static routes, RIP v1/v2, OSPF, EIGRP, BGP (IP Plus feature set)
-
WAN encapsulations: PPP, HDLC, Frame Relay, ISDN, PPPoE (DSL deployments), Dial-on-Demand Routing (DDR) for backup links
-
HSRP for redundant router failover; NHRP for DMVPN hub-spoke architectures
-
Network Address Translation (NAT): Static, dynamic, PAT overloading for multi-user Internet access
QoS & Bandwidth Management
-
Base QoS: Weighted Fair Queuing (WFQ), traffic shaping
-
Advanced QoS (IP Plus): Low Latency Queuing (LLQ), Frame Relay Traffic Shaping (FRTS), WRED, DiffServ marking, LFI for VoIP over slow WAN links
-
VoIP support: H.323, SIP, RSVP for voice over IP branch telephony
Integrated Security Suite
-
Stateful IOS Firewall (Context-Based Access Control, CBAC): Deep packet inspection, dynamic ACLs, application filtering
-
Optional IOS IDS: Signature-based intrusion detection for threat mitigation
-
VPN technologies:
-
IPsec (56-bit DES / 168-bit 3DES encryption) for site-to-site branch tunnels
-
L2TP, L2F remote user VPN
-
Cisco Easy VPN Remote: Pull centralized security policies from headquarters VPN headends to simplify remote office deployments
-
Access control: Standard/extended ACLs, PAP/CHAP authentication, TACACS+, RADIUS AAA for user login audit
-
Encrypted IOS images subject to US export regulations for global deploymentsCisco
Management & Operations
-
CLI command-line management via console/AUX
-
SNMP v1/v2c for network monitoring, RMON traffic statistics
-
Cisco ConfigMaker graphical configuration tool for simplified zero-touch deployment
-
AutoInstall: Remote automated config download over WAN links
-
Dual Flash bank: Store primary and backup IOS images for disaster recovery
-
Syslog logging, NTP time synchronization
4. Typical Deployment Scenarios
-
Small retail branch office: Single Fast Ethernet LAN, DSL WIC primary Internet link, ISDN BRI WIC for dial backup, IPsec site-to-site VPN to corporate headquarters, integrated firewall for POS terminal security
-
Remote field M2M site: Serial WIC for leased-line industrial SCADA connectivity, AUX-port modem remote management, NAT for multiple IoT sensors
-
SMB headquarters edge router: Dual serial WICs for redundant T1 leased lines, remote worker L2TP IPsec VPN termination, QoS prioritization for VoIP office phones
-
Legacy ISDN DSL carrier customer premise equipment: Annex B/J ISDN WIC primary access, Ethernet for small office PC LAN, firewall protection against Internet threats
5. Standard Package Contents
1 × Cisco 1720 base router chassis (no WIC cards, no power supply included)
Console RJ45-to-RS232 rollover cable
Hardware installation guide
Regulatory safety & RoHS compliance documentation
Separately Sold Optional Accessories
-
External 12V DC power adapter
-
WAN Interface Cards (WICs: ISDN, serial, T1, DSL variants)
-
CAT5e RJ45 Ethernet patch cords
-
RJ11 ISDN/DSL telephone cables
-
USB flash storage for offline config backups
-
Third-party 19-inch rackmount brackets
-
External PoE injectors for IP cameras/Wi-Fi APs
Short Commercial Catalog Summary
The Cisco 1720 is a legacy fanless modular VPN access router from the Cisco 1700 Series, purpose-built for small SMBs and tiny enterprise branch offices. Equipped with two universal WIC expansion slots for flexible DSL, ISDN, serial, or T1 WAN connectivity, one fixed 10/100 Fast Ethernet LAN port, console and AUX management ports, it runs feature-rich Cisco IOS software delivering integrated stateful firewall, IPsec VPN, AAA security, and basic QoS bandwidth management. Supporting a broad ecosystem of shared WIC cards compatible with older Cisco router families, it consolidates routing, remote access, and security functions into a single compact desktop unit to reduce multi-device deployment costs. Key limitations include a maximum of 48MB DRAM / 16MB Flash, lack of native 802.1Q inter-VLAN routing, and outdated hardware performance compared to modern ISR platforms. The Cisco 1720 reached end-of-life and is no longer supported by Cisco, recommended only for legacy lab or non-production environments, with the Cisco 1000 Series ISR as its modern replacement.
|
