User:CBaker007/Cisco Modular Access Routers

Cisco Modular Access Routers
Cisco Systems was founded on the sucessful commercial production of a multiprotocol router running their Cisco IOS. While Cisco has diversified their product portfolio over the years reducing the dominance router sales has played in their annual sales revenue, their modular access router is still a core component of the Cisco portfolio.

Despite the diversification in Cisco's portfolio, they continue to dominate the router market with 60% of all sales. Their modular access routers are a major component of their router portfolio.

While early versions of their commerical multiprotocol routers based on the Cisco IOS were, for the most part, fixed port configurations as seen in the Cisco 2500 series routers, future versions moved to a more modular design.

While all their routers run the core Cisco IOS software, various "series" of routers are typically offered at any one time (ie - 800 series, 1800 series, 2800 series). These series typically offer an increasingly faster CPU/core system that has a higher "throughput" and/or processing power to allow more complex versions of the Cisco IOS as well as higher port densities. Within each series the biggest difference between models is typically the number of fixed ports and the number and type of expansion slots.

Operating System
Cisco modular access routers and most of their high end routers (7000 series and above) run Cisco's proprietary operating system called the Cisco Internetwork Operating System (aka - Cisco IOS).

The Cisco IOS is sold in various versions called "Feature Sets". The base version is typically the "IP Base" version which supports basic IP routing features. Other versions include support for advanced IP routing, routing other protocols, voice functions, security functions, etc. The exact Feature Set needed can be determined using Cisco's Feature Navigator.

The IOS is typically a single file installed on the router's flash memory that is dynamically expanded on bootup. The IOS file is hardware specific. In other words an "IP Base" IOS image for a 2800 series router will not run on a 1600 series router.

Management
Typical management of Cisco routers is via Cisco's well established command line interface (CLI) for which the core features of the interface has been used on every modular access router. The CLI has added commands and features as the IOS has grown, but the common interface has greatly added to its popularity.

Initial router programming is typically done via a directly connected console (serial) port. After a network connection has been established, management can be done via telnet, SSH telnet, SNMP, HTTP, and HTTPS.

After a base configuration is placed on the router, it is possible to enable other management options including web based management built into the IOS as well as external management programs including:
 * Cisco Security Device Manager (SDM)
 * Cisco Network Assistant
 * CiscoWorks
 * Various 3rd Party Management Tools

Memory (Flash & DRAM)
Cisco routers typically have two types of memory, flash and DRAM. Flash is a non-volatile memory (information not lost when powered off) where the operating system (IOS), configuration files, and licensing files are stored. DRAM is the volatile memory used by the system after bootup.

While some models are fixed configuration and upgrading flash and/or DRAM is not supported, most models allow upgrades to flash and DRAM within certain limitations. Typically the base flash and DRAM will adequately support the base IOS called IP Base. Upgrades to DRAM and flash are typically required in order to support upgrades to the IOS to more advanced feature sets.

Cisco offers memory upgrades for routers that can be upgraded and strongly recommends that customers use memory purchased from Cisco. Cisco's official policy allows for thrid party upgrades but Cisco may at its discretion "withhold support under warranty or a Cisco support program such as SMARTnet™ service" if the problem "can be traced to the use of [a] third-party" product.

Module Types
WIC Form Factor Cards


 * WAN Interface Card (WIC) - Wide Area Network (WAN) type ports including serial, Data ISDN (BRI), T1, and other WAN data interfaces.


 * High-Speed WIC (HWIC) - Updated versions of select WIC modules with higher densities.


 * Voice Interface Card (VIC) - Modules for voice interfaces including Plain Old Telephone Service (POTS), Foreign Exchange Office(FXO), Voice ISDN (PRI), Foreign Exchange Station (FXS), etc.


 * WAN/Voice Interface Card (WVIC) - Cards that support both Voice and Data (WAN) like ISDN cards that can be configured for both voice and/or data services.

Network Module Form Factor Cards


 * Network Module (NM)


 * Network Module Enhanced (NME)


 * NME-X

Internal Upgrade Cards


 * Advanced Integration Module (AIM)
 * Digital Signal Processing Module (DSP)