Home | Articles | About | Contact | Forum |
Wednesday, September 28, 2016



Lunarpages.com Web Hosting

Mailing List

E-mail:
By Joining the mailing list you will be notified of site updates.


Show Your Support For
This Site By Donating:











Audience: Newbies - System Admins
Last Updated: 3/21/2011 8:55 PM
Original Creation Date: 2/14/04 1:55 PM
**All times are EST**





Cisco Router Hardware

By Erik Rodriguez

This article describes the internal components of a cisco router. It would benefit anyone who wants to learn more about routing networks and how routers work.


Routers are nothing more than a special type of PC. Routers and PCs both have some of the same components such as a motherboard, RAM, and an operating system. The main difference is between a router and standard PC, is that a router performs special tasks to control or "route" traffic between two or more networks. Remember that routers are the "smartest" networking devices. They operate at layer 3 of the OSI model. If you are unsure of the difference between a router, switch, or hub click here.

Hardware Components


There are 7 major internal components of a router:
  • CPU
  • RAM
  • NVRAM
  • Flash
  • ROM
  • Console
  • Interfaces

CPU
The CPU performs functions just as it does in a normal PC. It executes commands given by the IOS using other hardware components. High-end routers may contain multiple processors or extra slots to add more CPUs later.

RAM
Random Access Memory; this component is dynamic. Meaning, its content changes constantly. The main role of the RAM is to: hold the ARP cache, Store routing tables, hold fast-switching cache, performs packet buffering, and hold queues. It also provides temporary memory for the configuration file of the router while the router is powered on. However, the RAM loses content when router is restarted or powered off. This component is upgradeable!

NVRAM
Nonvolatile RAM is used to store the startup configuration files. This type of RAM does not lose its content when the router is restarted or powered off.

Flash
Flash memory is very important because it saves your ass if you screw up the operating system configuration. It holds the Cisco IOS image file, as well as backups. This flash memory is classified as an EEPROM (Electronically Erasable Programmable Read Only Memory). The flash ROM is upgradeable in most Cisco routers.

ROM
The ROM performs the same operations as a BIOS. It holds information about the systems hardware components and runs POST when the router first starts up. This component can be upgraded by "unplugging" the chip and installing a new one. A ROM upgrade ensures newer versions of the IOS.

Console
The console consists of the physical plugs and jacks on the router. The purpose of the console is to provide access for configurations.

Interfaces
The interfaces provide connectivity to LAN, WAN, and Console/Aux. They can be RJ-45 jacks soldered onto the motherboard, transceiver modules, or card modules. Cisco routers, especially the higher-end models, can be configured in many different ways. They can use a combination of transceivers, card modules and onboard interfaces.

The picture below shows the components of a Cisco 804 ISDN router. Click to enlarge:





Contact Us

If you found this information useful, click the +1 button



Your E-mail:


Subject:


Type verification image:
verification image, type it in the box

Message:


NOTE: this form DOES NOT e-mail this article, it sends feedback to the author.

TCP vs. UDP
Juniper SRX anti-spam filtering config
Windows Server 2008 Clustering Configuration
Windows 2008 R2 Network Load Balancing (NLB)
Extreme Networks: Downloading new software image
Juniper SRX save config to USB drive
Juniper SRX logout sessions
Extreme Networks Syslog Configuration
Command line drive mapping
Neoscale vs. Decru
Data Security vs. Data Protection
Juniper SRX Cluster Configuration
HOWTO - Create VLAN on Extreme Switch
Using a Non-local Colocation Facility
Linux Server Administration
IT Chop Shops
Flow Viewers: SFLOW, NetFLOW, and JFLOW
Exchange 2007 Back Pressure
IPtables open port for specific IP
Politics in IT Departments
HOWTO - Block Dropbox
Cisco IOS Cheat Sheet
Subnet Cheat Sheet
Design a DMZ Network
How DNS works
Firewall Configuration
Juniper SSG Firewalls
Server Management
Configuring VLANs
Runlevels in Linux
Server Clustering
SONET Networks
The Red Hat Network
Server Colocation
Complicated Linux Servers
Dark Fiber
Data Center Network Design
Firewall Types
Colocation Bandwidth








Copyright © 2002-2016 Skullbox.Net All Rights Reserved.
A division of Orlando Tech Works, LLC
By using this site you agree to its Terms and Conditions.
Contact Erik Rodriguez