The New Cisco ISR 4461-FAQ

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Cisco ISR 4461 is the newest number of Cisco 4000 Family Integrated Services Router.

Now the Cisco 4000 Family contains the following platforms: the 4461 ISR4451 ISR4431 ISR4351 ISR4331 ISR4321 ISR and 4221 ISR.
Explore the 4000 Series ISR models

The 4000 Series offers solutions for highly secure SD-WAN connectivity, application experience, unified communications, network automation, virtualization, and branch and direct Internet access security–all in one platform.

ISR 4221 ISR 4321 ISR 4331
  • GE/SFP integrated WAN ports
  • 1.2-Gbps performance
  • 75-Mbps encrypted throughput
  • Full IOS XE SD-WAN support
  • Cyberthreat protection through Trustworthy Systems framework
  • GE/SFP integrated WAN ports
  • 2-Gbps+ performance
  • 100-Mbps encrypted throughput
  • Full IOS XE SD-WAN support
  • Cyberthreat protection through Trustworthy Systems framework
  • GE/SFP integrated WAN ports
  • 2-Gbps+ performance
  • 500-Mbps encrypted throughput
  • Full IOS XE SD-WAN support
  • Cyberthreat protection through Trustworthy Systems framework
ISR 4351 ISR 4431 ISR 4451 ISR 4461 (new)
  • PoE GE/SFP, GE/SFP integrated WAN ports
  • 2-Gbps+ performance
  • 500-Mbps encrypted throughput
  • Full IOS XE SD-WAN support
  • Cyberthreat protection through Trustworthy Systems framework
  • PoE GE/SFP, GE/SFP integrated WAN ports
  • 4-Gbps + performance
  • 900-Mbps encrypted throughput
  • Cyberthreat protection through Trustworthy Systems framework
  • PoE GE/SFP, GE/SFP integrated WAN ports
  • 4-Gbps+ performance
  • 1.6-Gbps encrypted throughput
  • Cyberthreat protection through Trustworthy Systems framework
  • 10 GE SFP+, PoE GE/SFP, GE/SFP integrated WAN ports
  • 10-Gbps+ performance
  • 7-Gbps encrypted throughput
  • Cyberthreat protection through Trustworthy Systems framework
Read the general questions and answers to help you know the new ISR 4461 features.

Q. Where do I position the Cisco 4461 and the 4451-X in comparison to the Cisco 3900 Series ISRs and the ASR 1000 Series Aggregation Services Routers?

A. The Cisco 4451-X is positioned for high-end enterprise branch offices or enterprise headend where there is a performance requirement of 1 to 2 Gbps with services (4Gbps without services). Performance-wise the Cisco 4451-X is positioned between the 3945E ISR and the ASR 1001. Similarly, the 4461 is proposed for branch locations where the router performance requirement varies between 1.5Gbps and 3Gbps with services (nearly 10Gbps without services)

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Q. What software are the Cisco 4461 Series ISRs capable of running?

A. The ISR4461 was released with the 16.9.1 IOS XE software release. The 4000 Series ISRs run Cisco IOS ® XE Software. The initial version will be Cisco IOS XE Software Release 3.9.1. The 4300 and 4431 ISRs were released with Cisco IOS XE Software Release 3.13, and the 4200 Series ISRs were released with Cisco IOS XE Software Release 16.4.1.

Q. Do Cisco 4461 routers support 10Gbps natively?

A. Yes, the Cisco 4461 supports two 10Gbps on the front panel interfaces using either of Ethernet or Fiber Optics.

Q. Can I support more than one double-wide Service Module on the Cisco ISR 4461?

A. Yes, the Cisco 4461 supports upto two double-wide Service Modules (SM). However the same router can support only three single wide SM modules. Only one of the lower slots supports a single-wide SM module.

Q. What memory upgrade options are available on the Cisco 4461?

A. The 4461 comes with 8GB of memory as the default and is upgradeable to 32GB. The 4000 Series has separate data and control-plane memory. The control-plane memory comes with 4 GB as the default, and is upgradable up to 16 GB based on various platforms. The data-plane memory comes with 2 GB as the default and is not currently upgradable.

Q. How many Dual Inline Memory Modules (DIMMs) does the 4461 have?

A. The 4461 has one DIMM slot for memory and maybe upgraded to 16GB or 32GB of memory on that single slot using the appropriately sized DRAM memory. The 4451-X and 4431 have three DIMM slots. Two slots are used for control-plane and one slot for data-plane memory. The 4331 and the 4351 have two DIMMs, and the 4321 has one DIMM slot. The 4221 has no DIMM slot for memory expansion.

Q. In the case of control-plane memory, can I put, say, a 4-GB DIMM in one slot and a 2-GB DIMM in the other slot?

A. No. Like the Cisco 3900 Series, the 4000 Series expects both DIMM slots to have the same size of memory; as an example, it must have either 4-GB memory in both slots for a total of 8 GB of control-plane memory, or 2-GB memory in both slots, for a total of 4 GB of control-plane memory. This setup is necessary because these platforms interleave memory devices for faster access.

On the 4461, as there is a single DIMM slot, it can be populated by a single 16GB or 32GB of memory card.

Q. Do all four ports with both RJ-45 and Small Form-Factor Pluggable (SFP) front panel Gigabit Ethernet (FPGE) connections support failover?

A. Yes. You can configure auto-failover on any of the front-panel ports with both RJ-45 and SFP connections. When auto-failover is configured, if the primary interface type fails, either RJ-45 or SFP, the other media type becomes active and allows traffic to continue over the backup physical connection. In this scenario, the backup connection needs to be connected with the same speed and duplex as the primary connection.

Note that the auto-failover feature as described does support one Gigabit Ethernet interface acting as a backup to another. The two physical connections available on a single Gigabit Ethernet interface simply provide failover if a link fails.

Q. What type of backplane is used between components in the Cisco 4000 Series?

A. The 4000 Series uses multigigabit fabric (MGF) for Layer 2 connectivity between the modules. On the 4451-X, the MGF can provide either 2 Gbps to all NIM slots or up to 10 Gbps to all SM-X slots. The MGF is completely nonblocking and can forward in excess of 50 Gbps.

Q. What power cables work with the Cisco 4000 Series?

A. All power-supply options for the 4000 Series use a standard IEC C13 connector. No special IEC C15 cord is necessary for the Power over Ethernet (PoE) power supply because higher-efficiency power supplies (85 percent) are used in the 4000 Series. This cord thus helps lower the maximum current the power supplies can draw.

Q. Are the Cisco 4461, 4451-X and 4431 power supplies Field-Replaceable Units (FRUs)?

A. Yes. The power supplies can be replaced in the field.

Q. Are the Cisco 4461, 4451-X and 4431 power supplies hot-swappable?

A. Yes. You do not need to power down the chassis to insert or remove a power supply. Also, unlike the 3900 Series ISRs, the bezel and fan tray can remain in place while a power supply is replaced.

Q. Does the Cisco 4000 Series have a DC power-supply option?

A. Yes, the Cisco 4400 Series and the two models of 4331 ISR and 4351 ISR provide support for DC power supplies. PoE modules may not be used when DC power supplies are used.

Q. What are the power options for PoE on the Cisco 4000 Series?

A. The Cisco 4461, 4451-X and 4431 have two PoE options. Two of the FPGE interfaces can be powered with the addition of a dedicated power-conversion module installed into the system (PWR-GE-POE-4400). This module does not require a higher-capacity system power supply and will work with the default power supply. The PoE power for the FPGE ports is completely independent from PoE power to the rest of the system.

The Cisco 4000 Series also has the option of a PoE power supply to provide PoE power to modules in the system such as an Ethernet switch module. The Cisco 4400 series can accept up to two PoE power supplies and power-conversion modules for redundant operation or PoE Boost mode. The PoE power supply in the 4400 series actually includes two components as a single part: a higher-capacity system power supply and a PoE conversion module that converts system power into PoE for modules within the system.

Q. What is the difference between PoE Redundancy mode and PoE Boost mode?

A. Both modes require that two power supplies be installed in the Cisco 4400 series. Redundancy mode provides backup PoE power to the chassis; full PoE power will be available in the event of a single power supply failure. PoE Boost mode provides double available PoE power—the maximum amount of power from both power supplies combined—meaning that if a single power supply fails the second redundant power supply will be cut in half.

Q. With redundant power supplies, can we switch the power to primary when it fails and the router is running on the secondary power supply?

A. There is no concept of primary or secondary power supply for the Cisco 4400 series. The power supplies are simply redundant, so that when one fails the other Power-Supply Unit (PSU) takes over by transparently providing power to the entire system. No switching or intervention is required. Both share the load when running in the system; however, when one fails the other provides power to the complete unit. When the failed PSU is replaced with a new PSU in the system, the two power supplies are redundant.

Q. Are the PoE interfaces PoE+?

A. PoE+ is available on the new SM-X Ethernet switch modules as well as on the FPGE ports.

Q. How does the system fan speed vary?

A. The Cisco 4000 Series ISRs use both an inlet temperature and an altitude sensor to determine the best fan-speed setting. There are four different inlet temperature ranges and five different altitude ranges for a total of 20 possible different fan-speed settings. The addition of an altitude sensor is an industry first for a branch-office platform. With altitude data incorporated into the fan speed, the system can account for the density of air cooling in order to select the most efficient and quietest fan-speed setting. All system fans run at the same speed.

Q. Can the Cisco 4000 Series ISRs handle the failure of a fan?

A. Yes, for systems with multiple fans (4331 and above). A fully loaded system will function normally below 6000 feet (1.82 km) with a single fan failure. If the ISR is above 6000 feet and in 32ºF (or 0ºC) temperatures it may shut down because of overheating. The system is rated to operate in 32ºF temperatures at up to 10,000 feet (3.05 km).

Failure of a power-supply fan will likely result in overheating and shutdown of the power supply. If power redundancy is required, you should install two power supplies in an ISR4400 series router.

Q. Is a rack-mount kit available for the Cisco 4000 Series? How do I order it?

A. Yes. A rack-mount kit is part of the default accessory kit and is shipped with the Cisco 4000 Series. Order part number ACS-4450-RM-19= for the spare 19-inch rack-mount kit for the 4451-X. Similarly, for the 4321, 4331, 4351, and 4431, you may use ACS-4320-RM-19=, ACS-4330-RM-19=, ACS-4430-RM-19=, and ACS-4450-RM-19=, respectively. For the new 4461 you may use ACS-4460-RM-19= for the 19-inch rack kit

Q. Is a 23-inch telco rack-mount kit available for the Cisco 4000 Series?

A. Order part number ACS-4450-RM-23= for the spare 23-inch rack-mount kit for the Cisco 4451-X. For the 4461 the spare part code ACS-4460-RM-23= maybe ordered. Similarly, order the ACS-4430-RM-23= for the Cisco 4431 and the ACS-4330-RM-23= for the Cisco 4351 or 4331.

Q. How can I calculate the Mean Time between Failures (MTBF) information for the Cisco 4451-X with the plugged-in modules? Is a MTBF calculator available, such as for the ISR G2 routers?

A. The MTBF for all the routers is listed on the data sheet at

Q. What else is part of the default accessory kit?

A. The default accessory kit includes:

  • Mechanical ground lug 90 feet per screw kit
  • 19-inch rack-mount kit
  • Regulatory Compliance and Safety Information (RCSI) roadmap document
  • Plastic bag
  • Shipping label
  • Document pointer card for Cisco router

Q. What is the purpose of the GigabitEthernet0 on the Cisco 4000 Series?

A. The GigabitEthernet0 is the dedicated management port on the Cisco 4000 Series. This interface connects directly to the control-plane CPU and is ideal for managing the router through Telnet, Secure Shell (SSH) Protocol, Simple Network Management Protocol (SNMP), and other management protocols. It is also ideal for downloading software images, uploading logs, and connecting to other management devices such as RADIUS, Network Time Protocol (NTP), Domain Name System (DNS), Dynamic Host Configuration Protocol (DHCP), and TACACS servers. This interface should never be used for forwarding normal data traffic through the system because every packet goes directly to the control-plane CPU, bypassing the platform data plane. Because of this sensitivity, G0 is in a dedicated Mgmt-Intf Virtual Route Forwarding (VRF) port by default. This setup prevents accidental routing mistakes that could cause data traffic to be routed to the management network.

Q. Is MDI-X supported on the management RJ-45 Ethernet interface? Yes.

Q. Is a console port available on the Cisco 4000 Series?

A. The Cisco 4000 Series has the option of the regular RJ-45 console port as well as the USB console port. As with the ISR G2 routers, only one console port can be used at a time, with preference given to the USB console port. The Cisco 4221 router has a combo RJ-45 port for AUX and Console.

Q. Is Online Insertion and Removal (OIR) supported on the Cisco 4000 Series?

A. Yes, OIR is supported on the Cisco 4000 [1]Series for the following scenarios:

  1. Surprise insertion or removal of any NIM in any of the NIM slots
  2. Surprise insertion or removal of any SM-X in the SM-X slots
  3. Surprise insertion or removal of any power supply or system PoE conversion module
  4. Surprise replacement of the system fan tray; note, however, that this replacement must take place quickly enough that the system does not overheat, and depending on altitude and ambient temperature, the amount of time can vary greatly

Note that SM-X and NIM modules allow replacement only for like-to-like modules. A faulty module can be replaced with a good module of the same type but cannot be replaced with a completely different module of a different type.

Q. Will the NIMs and service modules continue to function as they normally do after OIR on a Cisco 4000 Series ISR?

A. Yes, provided the OIR was carried out using a like-for-like module.

The Newest Updated: Cisco 4000 Series Integrated Services Routers FAQ

More Data Sheets:

Cisco Integrated Services Routers 4000 Series Data Sheet

Comparison of Cisco ISR 4000 Models

Guide to Select New Cisco Routers

Guide to Upgrade Your ISR G1 and ISR G2 Routers to ISR 4000

More Related:

The “Always On” Cisco ISR 4000 Will Replace the Popular Cisco 1900, 2900, and 3900 Series

Migrate to ISR 4000 Series Now

Performance Comparison of Cisco 4000 with Cisco ISR G2 Routers

New: About Cisco 4000 Series ISR Gigabit Ethernet WAN Modules

New Cisco NIM cards for Cisco ISR 4000 Family


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