Non−Volatile RAM (NVRAM), PCMCIA Flash, and WIC.
Input/Output (I/O) Buses allow the M68360 to individually control other devices through the
SCCs. These include Universal Asynchronous Receiver/Transmitter (UART), the Ethernet
controller, and the WAN port interface.
♦
UART is an SCC integrated on the M68360. It provides the necessary user interface. It has one
RS232 port, and a data communications equipment (DCE) (console) RJ45. Note: UART has no
Auxiliary (data terminal equipment − DTE) port. Higher console speeds (upto 115.2 Kbps) are
supported. The downloading of Cisco IOS software images over the console port is supported using
xmodem or ymodem.
•
WAN interface cards (WICs) are media−specific network interfaces responsible for data transfer in
and out of the 160x series router. WICs communicate with the CPU through the CPU Bus for packet
transfer. Specialized Controllers (or application−specific integrated circuits − ASICs) used for media
support perform the above−mentioned functionality. WICs do not support Online Insertion and
Removal (OIR).
•
Power supply provides power to various components of the router.•
Memory Details
Different kinds of memory reside in the Cisco 1600 Series router, and each of them is handled in a different
way and for different purposes.
DRAM is logically divided in Main Processor memory and Shared Input/Output (I/O) memory.
Main Processor memory is used to store routing tables, fast switching cache, running configuration,
and so on. It can take unused shared I/O memory, if needed.
•
Shared I/O memory is used for temporary storage of packets in system buffers during process
switching, and interface buffers during fast switching. Cisco 1600 series routers running Cisco IOS
software versions prior to the integration of CSCdk40685 have a fixed I/O memory of 512 KB. (To
see details about this bug, go to the Bug Toolkit and type in CSCdk40685). After CSCdk40685, if the
router has enough memory, it allocates 25% to I/O memory. If not, I/O memory remains at 512 KB.
•
The way DRAM memory is distributed can be seen using the show memory summary command:
Router−1600#show memory summary
Head Total(b) Used(b) Free(b) Lowest(b) Largest(b)
Processor 20B3A7C 13419908 2334632 11085276 10907924 10907920
I/O 2D80000 4718592 247324 4471268 4466128 4464852
Physically, DRAM is a combination of 2 MB on−board non−parity chips, and one Single In−line Memory
Cisco 1600 Series Router Architecture