Cisco 2651 Multiservice Modular Access Router Full Product Description

1. Short Overview

Naming & Variant Breakdown

• C2651/K9: Base crypto-enabled multiservice router
• C2651XM/K9: Extended Memory upgraded model with expanded memory and higher multi-service throughput
• C2651-DC/K9: 48V DC-powered variant for telecom central office rack deployments
• -V: Voice pre-licensed bundle for Cisco CME IP call processing

Core Differentiators vs Cisco 2621

1. Faster 80 MHz MPC860P CPU (50 MHz on 2621) for heavy mixed voice, security, and VPN multi-service loads
2. Higher voice capacity: Supports up to 192 concurrent VoIP calls vs ~30 on the 2621 via high-density NM-HDV2 DSP modulesCisco
3. Native support for high-density T1/E1 PRI voice trunk NM modules for PBX interworking
4. Identical slot layout: 1 NM slot + 2 WIC slots + 1 internal AIM daughtercard slot
5. Dual 10/100 Fast Ethernet onboard ports for multi-VLAN internal segmentation
6. Uses 3.3V SDRAM (XM models) vs older EDO DRAM on base 2621 hardwareCisco

2. Hardware Interface & Physical Specifications

Modular Expansion Architecture (3 Total Modular Slots + Internal AIM Slot)

1. 1 × NM (Network Module) slot: Large high-density slot cross-compatible with Cisco 1600, 1700, 2600, 3600 Series modules for voice, WAN, and terminal server deployments:
   • Dual-T1/E1 PRI channelized trunk NM modules for PBX voice interconnection
   • NM-HDV / NM-HDV2 high-density DSP voice modules for VoIP, T.38 fax relay, and multi-party conferencing
   • ATM, Frame Relay, and 16-port analog modem terminal server modules
2. 2 × WIC (WAN Interface Card) slots: Interchangeable low-density WICs for backup and broadband access:
   • ISDN BRI, synchronous/asynchronous serial leased lines
   • ADSL, G.SHDSL copper broadband WICs (Annex A/M POTS and Annex B/J ISDN)
   • Dual-port serial and analog modem WICs for dial-on-demand backup links
3. Internal AIM (Advanced Integration Module) daughtercard slot: Accepts AIM-VPN, AIM-VOICE, AIM-ATM, or AIM-COMPRESS modules to offload CPU-intensive IPsec encryption, voice processing, ATM SAR, or data compression without consuming external WAN/NM slotsCisco.

Fixed Built-in Rear Panel Ports

1. 2 × 10/100BASE-TX autosensing Fast Ethernet LAN ports (RJ45)
   Auto-negotiates 10/100 Mbps full/half duplex; each port supports both Cisco ISL and IEEE 802.1Q VLAN trunking and inter-VLAN routing to separate distinct internal subnets (e.g., corporate staff LAN, guest Wi-Fi, POS payment networks).
2. RJ45 Console port (blue)– Local out-of-band CLI management, maximum baud rate 115.2 kbps
3. RJ45 AUX port (black)– Remote out-of-band management via external PSTN analog modem, asynchronous speed up to 115.2 kbps
4. Power inlet: Standard IEC AC socket (DC variant uses terminal block 48V DC telecom input)
5. Kensington anti-theft lock slot for physical rack chassis security

Memory & Performance Benchmarks

• Processor: Motorola MPC860P PowerQUICC 80 MHz RISC core
• Base C2651 default DRAM: 64MB; maximum expandable DRAM: 128MB 3.3V SDRAM
• C2651XM default DRAM: 128MB; maximum expandable DRAM: 256MB SDRAM
• Default Flash memory: 32MB (base) / 32MB (XM); maximum supported Flash: 32MB (base) / 48MB SIMM Flash (XM)Cisco
• Mixed voice/data packet forwarding throughput: Up to 20,000 pps (base) / 24,000 pps (XM)
• Onboard hardware crypto engine + AIM-VPN offload support: Native AES-256, 3DES, DES IPsec and SSL VPN acceleration
• Maximum concurrent site-to-site IPsec tunnels: Up to 100 (scales with DRAM and AIM-VPN crypto module)
• Supported IOS releases: Cisco IOS 12.2T, 12.3 mainline / 12.3T multiservice maintenance trains (XM models unlock extended voice, security, and QoS features unavailable on non-XM 2651)
• Voice capacity: NM-HDV2 DSP modules support up to 192 concurrent VoIP calls, multi-party conferencing, and T.38 fax relay; compatible with Cisco CME for up to 72 IP phonesCisco

Physical & Power Parameters

• Form factor: 1U standard 19-inch rack-mount metal chassis with integrated rack ears
• Standard power supply: Internal universal AC power supply (100–240V 50/60Hz input; no external DC wall adapter required)
• DC variant (C2651-DC): 48V DC terminal block input for telecom central office racks
• Typical chassis power draw: ~60W under fully loaded module configuration
• Front panel status LEDs: System power, fault alarm, NM slot activity, two WIC slot link/activity, dual Fast Ethernet link/activity, AIM module health
• Operating environment: Dry indoor wiring closet / office deployments only
  • Operating temperature: 0°C to +40°C below 1800m altitude; 0°C to +25°C above 1800m up to 3000m
  • Relative humidity: 10–85% RH non-condensing
• Dimensions (H × W × D): 4.3 × 44.5 × 30 cm (1.69 × 17.5 × 11.8 inches)
• Weight: ~4.8 kg (10.6 lbs) fully loaded with NM/WIC/AIM modules
• No native chassis PoE output; IP cameras and wireless APs require external PoE injectors.

3. Cisco IOS Multiservice Feature Suite

Core Routing & Multi-WAN Connectivity

• Full IPv4 routing stack: Static routes, RIP v1/v2, OSPF, EIGRP, BGP (IP Plus feature set)
• WAN encapsulations: PPP, HDLC, Frame Relay, ATM, ISDN, PPPoE for DSL, Dial-on-Demand Routing (DDR) for redundant backup links
• HSRP/VRRP for router failover redundancy; NHRP for DMVPN hub-spoke multi-site overlay VPN architectures
• NAT services: Static NAT, dynamic NAT, PAT overloading for multi-user Internet access
• Dual VLAN trunking standards support: ISL and IEEE 802.1Q for inter-VLAN routing across the two onboard Fast Ethernet ports and downstream switches.

Multiservice Voice & Fax Integration (Key High-Density Voice Differentiator)

1. VoIP call control protocols: H.323, SIP, MGCP, SCCP for Cisco Unified IP Phone integration
2. Analog/digital telephony via NM-HDV2 DSP + VIC voice cards: FXS station ports, FXO PSTN trunk ports, E&M PBX tie-line support, E1/T1 PRI trunk interworking with third-party PBXs (Nortel, Siemens, Avaya)Cisco
3. T.38 real-time fax relay over IP, fax passthrough, store-and-forward fax
4. Voice compression codecs: G.711, G.729a, G.726 with hardware DSP acceleration to reduce WAN bandwidth consumption
5. Multi-site dial plans, voice hunt groups, toll bypass to eliminate costly long-distance PSTN telephony charges
6. Cisco CME embedded call processing for up to 72 IP phones, Unity Express voice messaging support via AIM storage modules

Enterprise QoS & Bandwidth Management

• Base QoS tools: Weighted Fair Queuing (WFQ), traffic shaping
• Advanced QoS (IP Plus image): Low Latency Queuing (LLQ), Frame Relay Traffic Shaping (FRTS), WRED, DSCP/802.1p marking, Link Fragmentation and Interleaving (LFI) to eliminate voice jitter over low-speed WAN links
• cRTP VoIP header compression to cut packet overhead on DSL and ISDN backup circuits.

Integrated Self-Defending Network Security

1. IOS Context-Based Access Control (CBAC) stateful firewall: Dynamic deep packet inspection for HTTP, FTP, SIP, H.323, and other business applications
2. Optional IOS signature-based IDS for inline intrusion detection and real-time threat mitigation
3. Hardware-accelerated VPN suite (with AIM-VPN module):
   • AES-256/3DES/DES IPsec site-to-site branch tunnels
   • Cisco Easy VPN Remote for centralized security policy deployment to remote branch locations
   • L2TP/L2F remote worker user VPNs
4. AAA security framework: PAP/CHAP authentication, RADIUS/TACACS+ centralized access control and audit logging
5. Standard/extended ACLs, dynamic ACLs, anti-DDoS policing, and traffic segmentation to isolate sensitive subnets (e.g., POS payment VLANs).

Management & Operations

• Dual out-of-band management: RJ45 serial Console and AUX modem port
• Secure remote access: SSHv2, HTTPS, SNMP v1/v2c network monitoring with RMON traffic statistics
• Graphical configuration tool: Cisco Configuration Professional (CCP) for simplified zero-touch deployment
• AutoInstall automated remote configuration download over WAN links
• Single Flash bank storage for IOS image hosting (XM models support larger Flash upgrades)
• Syslog event logging, NTP time synchronization for consistent audit log timestamps.

4. Typical Deployment Scenarios

1. Medium multi-line retail flagship voice gateway: VDSL2 WIC primary broadband WAN, ISDN BRI WIC dial backup, NM-HDV2 high-density DSP module for dozens of store analog phones and fax machines, dual Fast Ethernet ports to isolate POS payment terminals from employee PC and guest Wi-Fi subnets, IPsec site-to-site DMVPN tunnel to corporate headquarters, integrated CBAC firewall for PCI DSS compliance.
2. Regional medium enterprise PBX interconnection router: Dual T1 PRI NM leased-line primary/secondary voice trunks to on-site PBX, analog modem AUX-port remote out-of-band management, multi-VLAN segmentation for finance, HR, engineering, and visitor subnets, LLQ QoS prioritization for business VoIP and video conferencing.
3. Global mixed POTS/ISDN DSL carrier managed voice-capable business CPE: Universal dual-standard DSL WIC copper broadband access, dual Fast Ethernet ports for multi-segment enterprise LAN, integrated security suite for customer threat protection, DMVPN overlay to carrier central service hub, CME embedded IP phone call processing for on-site staff.
4. Networking training lab high-density voice core router: Flexible NM/WIC modularity to teach serial, T1/E1 PRI, DSL, ISDN WAN connectivity, dual-standard ISL/802.1Q VLAN trunking, IPsec VPN, and enterprise voice gateway labs; XM variant expanded memory supports full-featured IOS 12.3T images unavailable on the base 2651.

5. Standard Package Contents of C2651 / C2651XM / C2651-DC

Separately Sold Optional Accessories

• WAN Interface Cards (WIC-1B-S/T, WIC-T1-DSU, WIC-VDSL2, WIC-2SERIAL, etc.)
• Network Modules (NM-2T1, NM-HDV, NM-HDV2, NM-16AM analog modem terminal server, etc.)
• VIC voice interface cards for analog/digital telephony trunking
• AIM daughtercards: AIM-VPN encryption, AIM-VOICE DSP offload, AIM-ATM, AIM-COMPRESS data compression modules
• DRAM memory expansion SIMMs (64MB / 128MB / 256MB for XM variants)
• 3.3V SIMM Flash memory upgrades (32MB / 48MB XM)
• CAT5e/CAT6 Gigabit Ethernet patch cords, RJ11 DSL/ISDN telephone line cables
• External PoE injectors for IP cameras and wireless access points
• External redundant power supply units (RPS-compatible variants)

Software Licensing Information

Short Commercial Catalog Summary