If the Cisco 1700 series router has only the minimum memory requirements installed, it cannot enable the VPN module.
To resolve this issue, boot the router.
Perform these steps:
Verify that the router has enough RAM to support the installed Cisco IOS Software image. To obtain this information, issue the dir flash: and meminfo commands at the ROM Monitor (ROMmon) prompt, as shown in this example:
ROMmon 1 > dir flash:
program load complete, entry point: 0x80008000, size: 0xb2a0
Directory of flash:
2 6474952 -rw- c1710-k9o3sy-mz.122-4.XM4.bin
ROMmon 2 > meminfo
Main memory size: 32 MB.
Available main memory starts at 0x10000, size 32768KB
IO (packet) memory size: 25 percent of main memory.
NVRAM size: 32KB
Total is the total memory allocated to the processor or I/O memory. This does not include the amount of memory taken up by the Cisco IOS Software.
Used is the amount of memory being used at the time the show memory summary command is issued.
Free is the amount of free memory available at the time the show memory summary command is issued.
Lowest is the lowest amount of memory available since the last reload.
Largest is the largest amount of free contiguous memory at the time the show memory summary command is issued.
i. In this sample output, the free I/O memory is very low (8756 bytes) and the free processor memory is large (12270168 bytes or about 12MB).
To have sufficient I/O memory, you can borrow memory from the processor pool by issuing the memory-size iomemi/o-memory-percentage global configuration command.
If the router has 32MB of RAM, the memory-size iomem 10 command allocates 10 percent of 32MB (3.2MB) to the I/O pool. In this example, the memory for the I/O pool is 2097152 bytes (about 2MB). This memory adds 1.2MB to the I/O pool and takes the same amount from the processor pool.
j. After issuing the memory-size iomem command, the configuration must be saved for the changes to take effect at the next reload.
6. If the router has been previously configured, perform these steps:
c. Issue the config-reg 0x2102 global configuration command so the router will not ignore the startup configuration, as shown in this example:
d. Power the router off.
e. Reinstall the VPN module and any WICs or VICs.
f. Power the router on.
g. If the router boots properly, check the backup configuration for the memory-size iomem command line. If this line is found, delete it and then go into global configuration mode and paste the backup configuration into the router.
h. Save the configuration by issuing the write memory or copy running-config startup-config command.