Empower Your Network with Cisco C921-4P: A High-Performance Connectivity Solution

Model: C921-4P – Cisco 921 Gigabit Ethernet security router with internal power supply
Detail: Cisco 921 Gigabit Ethernet security router with internal power supply

Description of Cisco C921-4P

C921-4P is the Cisco 921 Gigabit Ethernet security router with internal power supply. Cisco 900 Series ISRs deliver integrated security and threat defense, protecting networks from both known and new Internet vulnerabilities and attacks. These powerful, fixed-configuration routers provide secure broadband and Metro Ethernet connectivity. Service providers offering managed Ethernet WAN services can deploy them in customer locations as CPE.

                                   Centralized and remote management capabilities are available through web-based tools and Cisco IOS® Software for full visibility and control of network configurations at the remote site. The 900 Series ISRs simplify the deployment of Ethernet WAN services, with end-to-end Operations, Administration, and Maintenance (OA&M), Service-Level Agreement (SLA) monitoring and verification, and configuration management. This series ISRs come with a 4-port managed switch, providing LAN ports to connect multiple devices.

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Quick Spec of Cisco C921-4P

Table 1 shows the quick spec.

SKU C921-4P
WAN interfaces 2 ports Gigabit Ethernet (GE)
LAN interfaces 4-port GE managed switch
Integrated USB 2.0 Yes
Default and maximum DRAM Default 1 GB
Default and maximum flash memory 2 GB; not upgradable
Dimensions (H x W x D) 1.70 x 9.0 x 9.5 in. (4.32 x 22.86 x 24.13 cm) (includes rubber feet)

Product Details of Cisco C921-4P

Figure 1 shows the front panel of Cisco C921-4P.


#6-32 Ground screw GE LAN port
Power button GE LAN port
Reset button GE LAN port
Console Port GE WAN port
USB2.0 port GE WAN port

Figure 2 shows the back panel of C921-4P.

Note: ① Power Connector

C921-4P Specification

WAN interfaces 2 ports Gigabit Ethernet (GE)
LAN interfaces 4-port GE managed switch
Integrated USB 2.0 Yes
Maximum crypto throughput (bit-rate policed) 150 Mbps
Cisco IOS Software
IP and IP services ●  Routing Information Protocol Versions 1 and 2 (RIPv1 and RIPv2)

●  Generic Routing Encapsulation (GRE) and Multipoint GRE (MGRE)

●  Cisco Express Forwarding

●  Standard 802.1d Spanning Tree Protocol

●  Layer 2 Tunneling Protocol (L2TP)

●  L2TP Version 3 (L2TPv3)

●  Network Address Translation (NAT)

●  Dynamic Host Configuration Protocol (DHCP) server, relay, and client

●  Dynamic DNS

●  DNS Proxy

●  DNS Spoofing

●  Access Control Lists (ACLs)

●  IPv4 and IPv6 multicast

●  Open Shortest Path First (OSPF)

●  Border Gateway Protocol (BGP)

●  Performance Routing (PfR)

●  Enhanced Interior Gateway Routing Protocol (EIGRP)

●  Virtual Route Forwarding (VRF) Lite

●  Next Hop Resolution Protocol (NHRP)

●  Bidirectional Forwarding Detection (BFD)

●  Web Cache Communication Protocol (WCCP)

xDSL ●  True Multimode VDSL2 and ADSL2+ over Annex A, B, J, and M, including traditional G.DMT and T1.413

●  World-class interoperability with industry-standard DSL Access Multiplexer (DSLAM) chipsets

●  Highest field reliability with Impulse Noise Protection (INP) over Repetitive Electrical Impulse Noise (REIN) and single isolated impulse noise (SHINE), extended INP delay, G.INP, physical layer retransmission, Seamless Rate Adaptation (SRA), and Bitswap

●  VDSL2 Persistent Storage Device (PSD) profiles up to 17a/b with support for spectral shaping

●  VDSL2 vectoring to offer blazing fiber speeds over copper

●  Remote management with TR069 and CWMP

●  Investment protection with Gigabit Ethernet

Switch features ●  Auto Media Device In/Media Device Cross Over (MDI-MDX)

●  25 802.1Q VLANs

●  MAC filtering

●  Switched Port Analyzer (SPAN)

●  Storm control

●  Smart ports

●  Secure MAC address

●  Internet Group Management Protocol Version 3 (IGMPv3) snooping

●  802.1X

Security features Secure connectivity:

●  Secure Sockets Layer (SSL) VPN for secure remote access

●  Hardware-accelerated DES, 3DES, AES 128, AES 192, and AES 256

●  Public-Key-Infrastructure (PKI) support

●  50 IPsec tunnels

●  Cisco Easy VPN client and server

●  NAT transparency

●  Dynamic Multipoint VPN (DMVPN)

●  Tunnel-less Group Encrypted Transport VPN (GET VPN)

●  VRF-aware IPsec

●  IPsec over IPv6

●  Adaptive control technology

●  Session Initiation Protocol (SIP) application-layer gateway

●  Cisco IOS Firewall:

◦   Zone-based policy firewall

◦   VRF-aware stateful inspection routing firewall

◦   Stateful inspection transparent firewall

●  Advanced application inspection and control

●  HTTPS, FTP, and Telnet Authentication Proxy

●  Dynamic and static port security

●  Firewall stateful failover

●  VRF-aware firewall

●  Cisco IOS Software black and white lists

●  Integrated threat control:

◦   Intrusion Prevention System (IPS)

●  Control plane policing

●  Flexible packet matching

●  Network foundation protection

Quality of Service (QoS) ●  Low-Latency Queuing (LLQ)

●  Weighted Fair Queuing (WFQ)

●  Class-Based WFQ (CBWFQ)

●  Class-Based Traffic Shaping (CBTS)

●  Class-Based Traffic Policing (CBTP)

●  Policy-Based Routing (PBR)

●  Class-Based QoS MIB

●  Class of Service (CoS)-to-Differentiated Services Code Point (DSCP) mapping

●  Class-Based Weighted Random Early Detection (CBWRED)

●  Network-Based Application Recognition (NBAR)

●  Link Fragmentation and Interleaving (LFI)

●  Resource Reservation Protocol (RSVP)

●  Real-Time Transport Protocol (RTP) header compression (cRTP)

●  Differentiated Services (DiffServ)

●  QoS preclassify and prefragmentation

●  Hierarchical QoS (HQoS)

Management ●  Cisco Configuration Professional

●  Cisco Configuration Express

●  Cisco Configuration Engine support

●  Cisco AutoInstall

●  Cisco IP Service-Level Agreement (IP SLA)

●  Cisco IOS Embedded Event Manager (EEM)

●  CiscoWorks

●  Cisco Security Manager

●  Telnet, Simple Network Management Protocol Version 3 (SNMPv3), Secure Shell (SSH) Protocol, Command-Line Interface (CLI), and HTTP management


●  Cisco Next Generation Plug-and-Play (NG PnP) Protocol

High availability ●  Virtual Router Redundancy Protocol (VRRP) (RFC 2338)



Metro Ethernet ●  Ethernet OA&M

●  Ethernet Local Management Interface (E-LMI)

●  IP SLA for Ethernet

IPv6 ●  IPv6 addressing architecture

●  IPv6 name resolution

●  IPv6 statistics

●  IPv6 translation: Transport packets between IPv6-only and IPv4-only endpoints (NAT-Protocol Translation)

●  Internet Control Message Protocol Version 6 (ICMPv6)

●  IPv6 DHCP

●  OSPFv3

●  BGP4+

●  IPv6 Path Maximum Transmission Unit (PMTU)

●  IPv6 neighbor discovery

●  IPv6 stateless address autoconfiguration (SLAAC)

●  IPv6 multicast routing

Application visibility and control ●  NBAR2

●  Flexible NetFlow (FNF)

●  Performance Agent

Number of recommended users ●  50
Default and maximum DRAM ●  Default 1 GB
Default and maximum flash memory ●  2 GB on all Cisco 900 Series ISR models; not upgradable
WAN ●  Refer to Table 2 for details
LAN switch ●  Refer to Table 2 for details
Separate console ports ●  RJ-45
USB 2.0 ●  One USB 2.0 Type A port
Physical dimensions  H x W x D = 1.70 x 9.0 x 9.5 in. (4.32 x 22.86 x 24.13 cm) (includes rubber feet)
Power supply Power specifications:

●  AC input voltage: Universal 100 to 240 VAC

●  Frequency: 50 to 60 Hz

●  Internal power supply (C921-4P and C931-4P only)

Approvals and compliance Safety:

●  IEC 60950-1

●  UL 60950-1

●  CAN/CSA C22.2 No. 60950-1

●  EN 60950-1

●  AS/NZS 60950.1

●  Class I Equipment (C921-4P and C931-4P only)

●  Class III Equipment (C927-4P, C927-4PM, and C926-4P only)


●  47 CFR Part 15: 2006

◦   CISPR22: Edition 6.0: 2008

◦   CNS13438: 2006

◦   EN 300 386 V1.6.1

◦   EN 55032

◦   EN61000-3-2: 2006 [+ amd 1 & 2]

◦   EN61000-3-3: 2008

◦   ICES-003 Issue 5: 2012

◦   KN 22: 2009

●  TCVN 7189: 2009

●  VCCI: V-3/2012.04


●  CISPR24: 2010 [+ amd 1 & 2]

◦   EN300386: V1.6.1

◦   EN55024: 2010

◦   EN61000-6-1: 2007

◦   KN24: 2011

◦   TCVN 7317:2003

Environmental operating range ●  Nonoperating temperature: -40° to 158°F (-40° to 70°C)

●  Nonoperating humidity: 5% to 95% relative humidity (noncondensing)

●  Nonoperating altitude: 0 to 15,000 ft (0 to 4570 m)

●  Operating temperature: 0° to 50°C (de-rate 1°C per 1000-ft increase in altitude)

●  Operating humidity: 5% to 95% relative humidity (noncondensing)

●  Operating altitude: 0 to 10,000 ft (0 to 3000 m)