To upgrade Cisco IOS Software or enable new features, memory requirements must be met.
To determine the amount of Flash and DRAM, issue the show version command. Refer to the bold text in the output below. DRAM is divided logically, combining the two numbers to determine total DRAM. In this case, it is 45056K/4096K bytes (45056kB + 4096kB = 49152kB), which is equal to 48MB.
Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-JS56I-M), Version 12.1(5)T9, RELEASE SOFTWARE (fc1)
TAC Support: http://www.cisco.com/tac
Copyright (c) 1986-2001 by cisco Systems, Inc.
Compiled Sun 24-Jun-01 15:29 by cmong
Image text-base: 0x80008088, data-base: 0x8149F218
ROM: System Bootstrap, Version 12.1(3r)T2, RELEASE SOFTWARE (fc1)
R1 uptime is 9 weeks, 3 days, 2 hours, 32 minutes
System returned to ROM by power-on
System image file is "flash:c2600-js56i-mz.121-5.T9.bin"
cisco 2651 (MPC860P) processor (revision 0x200) with 45056K/4096K bytes of memory.
Processor board ID JAB04390J7N (1507969529)
M860P processor: part number 5, mask 1
X.25 software, Version 3.0.0.
SuperLAT software (copyright 1990 by Meridian Technology Corp).
TN3270 Emulation software.
2 FastEthernet/IEEE 802.3 interface(s)
1 Serial network interface(s)
32K bytes of non-volatile configuration memory.
32768K bytes of processor board System flash (Read/Write)
Configuration register is 0x2102
You can also see memory information using following commands: