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Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers Generation 2 Software Configuration Guide
Chapter       Basic Router Configuration
Configuring I/O Memory Allocation
For complete information on global parameter commands, see the Cisco IOS Release configuration 
guide documentation set. 
Configuring I/O Memory Allocation
To reallocate the percentage of DRAM in use for I/O memory and processor memory on Cisco 3925E 
and Cisco 3945E routers, use the memory-size iomem i/o-memory-percentage command in global 
configuration mode. To revert to the default memory allocation, use the no form of this command. This 
procedure enables smartinit.
Tip We recommend that you configure the memory-size iomem below 25%. Any value above 25% should be 
used only for enhancing IPSec performance.
When you specify the percentage of I/O memory in the command line, the processor memory 
automatically acquires the remaining percentage of DRAM memory. 
Example
The following example allocates 25% of the DRAM memory to I/O memory and the remaining 75% to 
processor memory: 
Router#config t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# memory-size iomem 5
IO memory size too small:  minimum IO memory size is 201M 
Router(config)# 
Router(config)# memory-size iomem ?
<5-50>  percentage of DRAM to use for I/O memory: 5, 10, 15, 20, 25, 30, 40, 50
Router(config)# memory-size iomem 25
Smart-init will be disabled and new I/O memory size will take effect upon reload.
Router(config)# end
Step 3
enable secret password
Example:
Router(config)# enable secret cr1ny5ho
Router(config)# 
Specifies an encrypted password to prevent 
unauthorized access to the router.
Step 4
no ip domain-lookup
Example:
Router(config)# no ip domain-lookup 
Router(config)# 
Disables the router from translating unfamiliar 
words (typos) into IP addresses.
Command Purpose
Syntax Description
i/o-memory-percentage The percentage of DRAM allocated to I/O memory. The values permitted 
are 5, 10, 15, 20, 25, 30, 40, and 50. A minimum of 201 MB of memory is 
required for I/O memory.