DRAM memory expandability Minimum DRAM required by the Cisco IOS release that shipped with the system. If your system requires more than 8 MB of Flash memory, the additional memory must be ordered separately. This feature set is available with Cisco IOS Release 11.0 and later releases. Memory All Cisco 2500 models include a minimum of 8 MB of Flash memory, except for the mission-specific routers which include 4 MB or 8 MB of Flash memory, depending upon the Cisco IOS software release you order. Additional Flash memory can be purchased to allow for dual banking or potential future code growth.
Primary memory is used to store the operating configuration, routing tables, caches, and queues.
Shared memory is used to store incoming and outgoing packets. In the table below, the physical configuration column lists the amount of DRAM SIMM memory supported. The system usage column lists how the system allocates the total DRAM memory installed.