Cisco ISR4331/K9

ISR4331/K9 router with Lifetime Warranty. 3 Gigabit Ethernet ports, 4 GB flash, 4 GB DRAM


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Cisco ISR4331/K9

Cisco ISR4331/K9 router with 3 Gigabit Ethernet ports, 2 Network Interface Module slots, 1 Service Module slot, 4 GB flash memory, 4 GB DRAM (default RAM)

Note: The ISR4331 has 4 physical 1G ports, but two of these ports are combined into a single logical interface. Because of this, a maximum of 3 1G ports can be used at any given time. This router can be configured to use 2x RJ45 and 1x SFP port, or 2x SFP and 1x RJ45 ports

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ISR 4331 Platform Overview

ISR 4331 Management Port Diagram


The Cisco 4000 series ISRs (Integrated Service Routers) are designed to greatly improve enterprise branch networks routing and network services. Because of their application-aware networking features and a wide array of voice, security and application expansion licenses, the ISR4000 series can be custom fitted to meet the needs of a wide variety of enterprise networks.



ISR 4331 Port Diagram

The Cisco ISR4331/K9 has 3 gigabit Ethernet ports, 2 network interface module slots and 1 service module slot. These 3 ports include one dedicated RJ-45 port, one dedicated SFP port, and one dual mode RJ-45/SFP port. This dual mode port can only be used as either copper of SFP at any given time, not both. Because of this, the ISR 4331 has a maximum of 3 usable 1G interfaces, even though 4 are physically present on the unit.

The software on the ISR4331/k9 follows a universal image scheme, providing all possible feature packs in a single image. This allows for future upgrades through security, voice, or application licensing without modification to the routers software version. Additional functionality can also be added to this router through the addition of service modules and interface cards. Addon cards are available for FXO/FXS, Ethernet port adapters, etc.


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Cisco ISR 4331 Router

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ISR4431/K9 Specs
10/100/1000 ports 3
RJ-45 based ports 2
SFP-based ports 2
Enhanced service-module slots 1
NIM slots 2
Default DDR3 DRAM 4 GB
Max memory DDR3 ECC DRAM (combined control/service/data planes) 16 GB
Default flash memory 4 GB
Maximum flash memory 16 GB
External USB 2.0 Slots 1
USB console port type B mini 1
Serial console port – RJ45 1
Serial auxiliary port RJ45 1
Dimensions H x W x D 1.75 x 17.25 x 17.25 in
Form Factor 1 rack unit (1RU)
Weight 13.5 lb (6.2 KG)


 Cisco ISR 4331 FAQs

How many ports does the ISR4331 Have?

The 4331 can be configured to use up to 3 1G ports by default. There are 4 physical ports on the device, 2 copper and 2 SFP, however 2 of those physical interfaces are combined into a single logical “dual-mode” port. This means that you can only use either the SFP or RJ45 port for that interface at any given time. This is indicated by the yellow port-number bar spanning both ports on the unit. This allows you to configure your router with either 2 SFP ports and 1 RJ45 port, OR 2 RJ45 ports and 1 SFP port.

Does this ISR4331/K9 come with a power supply?

Yes, the ISR 4331 has a build-in AC power supply, and ships with a power cable, console cable and Ethernet cable. This ensures you have everything you need to get started with this router included in the box.

Does this ISR4331/K9 come with rack mounts?

Yes it does! Although if you have a requirement for  mounting hardware please email or give us a call for details.

I need a router that will be able to handle full BGP tables. Will the ISR 4331 have enough memory?

That depends – on the current size of the table, and what other tasks you are using your router for. Specifically, if you intend to keep a full routing table, we recommend upgrading the memory on your ISR4331/K9 just to be safe. Because Cisco recommends using matching DIMMs on ISR 4K routers, we encourage you to install two new DIMMs at once. We recommend two MEM-4300-4G DIMMs (8G total) or two MEM-4300-8G DIMMs (16G total), depending on your requirements.

Can I Smart Net this router?

Yes – all of our ISR4331/K9 are ‘clean’, genuine and smartnet eligible. Check out our Cisco Excess page for more details. If you have concerns about the exact unit you will be receiving, such as country of origin, smart net status, hardware revision, or other specifics please contact us. We’d be happy to provide any information we can to put your mind at ease!


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