Cisco Cisco IOS Software Release 12.4(23)

This section provides context for the TOE evaluation by identifying the product type and describing the 
evaluated configuration.

The TOE operates within routers (which are internetworking devices) running the Cisco Internetwork 
Operating System (IOS). 

Routers that support the TOE have a number of common hardware characteristics.

Central processor that supports all system operations, such as an Intel Pentium, PowerPC, MIPS

Dynamic memory, used by the central processor for all system operations

Flash memory, used to store the operating system image

Non-volatile memory, which stores configuration parameters used to initialize the system at system 
startup

Multiple physical network interfaces (minimally two). Some models will have a fixed number and 
type of interfaces; some models will have slots that accept additional network interfaces.

The basic operation of a router is as follows: 

At system startup, the operating system is transferred from Flash memory to dynamic memory using 
a built-in hardware bootstrap. (Some models execute the operating systems directly from Flash 
memory.)

The operating system reads the configuration parameters from non-volatile memory, builds the 
necessary data structures in dynamic memory, and commences operation.

IP packets are forwarded to the router over one or more of it’s physical network interfaces, which 
processes them according to the system’s configuration and state information dynamically 
maintained by the router. This processing typically results in the IP packets being forwarded out of 
the router over another interface, or dropped in accordance with a configured policy.

DRAM

230591

NVRAM

CPU

Flash

Fixed

Network interfaces

Modular