Memory Systems - Cisco 4000 Manual

Table 1-3
Description
Processor
Main memory
(DRAM)
Secondary cache
memory
Shared memory
(DRAM)
Flash memory
NVRAM
Boot ROM
Boot Flash
1. The Orion microprocessor is based on the MIPS R4400 and is pin-compatible.
2. DRAM = dynamic random-access memory.
3. NVRAM = nonvolatile random-access memory.

Memory Systems

The Cisco 4000 series memory systems (see Figure 1-2) have the following functions:
•
Main memory—Stores the running configuration and routing tables. The Cisco IOS
software executes from main memory.
•
Shared memory—Used for packet buffering by the router's network interfaces.
•
Flash memory—Stores the operating system software image. In the Cisco 4500-M and
4700-M, the Flash memory also stores the boot helper software.
•
NVRAM—Stores the system configuration file and the virtual configuration register.
•
Boot EPROM—In the Cisco 4000-M, erasable programmable read-only memory
(EPROM)-based memory stores the boot helper—a subset of the Cisco IOS
software—and the ROM monitor. In the Cisco 4500-M and Cisco 4700-M, only the
ROM monitor is EPROM based. The boot helper image allows you to boot the router
Cisco 4000 Series Processor and Memory Specifications
Cisco 4000-M
40-MHz Motorola
68EC030
4, 8, 16, or 32 MB
2
None
4 or 16 MB
4 or 8 MB
3
128 KB
128 KB–8 MB
Not available
Cisco 4500-M
100-MHz IDT Orion
1
RISC
8, 16, or 32 MB
None
4, 8, or 16 MB
4, 8, 16, 32, or 64 MB
128 KB
128–512 KB
4–16 MB
Overview of the Cisco 4000 Series Routers 1-9
Memory Systems
Cisco 4700-M
133-MHz IDT Orion
RISC
16, 32, or 64 MB
512 KB
4, 8, or 16 MB
4, 8, 16, 32, or 64 MB
128 KB
128–512 KB
4–16 MB