Core Issue
The network modules for the 2600, 3600, and 3700 series routers sometimes require a certain Cisco IOS Software feature set in order to be recognized. ATM, voice, and switch modules require a Plus feature set, and Virtual Private Network (VPN) modules require an IP Security (IPSec) feature set in order to be recognized.
Resolution
To determine the software requirements and to upgrade to a compatible Cisco IOS train, refer to the Software Support for Hardware section of the Software Advisor. If the network module is still not recognized, verify that the installed Cisco IOS Software has the required feature set to support the module. Issue the show version command to determine the feature set. This is a sample command output:
3725ESW>enable
3725ESW#show version
Cisco Internetwork Operating System Software
IOS (tm) 3700 Software (C3725-IS-M), Version 12.2(11)T6, RELEASE
SOFTWARE (fc1)
TAC Support: http://www.cisco.com/tac
Copyright (c) 1986-2003 by cisco Systems, Inc.
Compiled Fri 14-Feb-03 18:50 by ccai
Image text-base: 0x60008940, data-base: 0x617C4000
ROM: System Bootstrap, Version 12.2(8r)T2, RELEASE SOFTWARE (fc1)
3725ESW uptime is 1 day, 17 hours, 49 minutes
System returned to ROM by reload
System image file is "flash:c3725-is-mz.122-11.T6.bin"
cisco 3725 (R7000) processor (revision 0.1) with 196608K/65536K bytes of
memory.
Processor board ID JMX0715L02P
R7000 CPU at 240Mhz, Implementation 39, Rev 3.3, 256KB L2 Cache
Bridging software.
X.25 software, Version 3.0.0.
SuperLAT software (copyright 1990 by Meridian Technology Corp).
38 FastEthernet/IEEE 802.3 interface(s)
DRAM configuration is 64 bits wide with parity disabled.
55K bytes of non-volatile configuration memory.
31744K bytes of ATA System CompactFlash (Read/Write)
Configuration register is 0x2102
Look at the second line of the show version command output. The feature set is designated by the characters between the dashes in the (C3725-IS-M) part of that line. In this case, IS represents the feature set, which stands for IP Plus.
If there is an S present, it indicates a Plus feature set. If the display shows (C3725-I-M), it indicates the Cisco IOS Software was a non-Plus version, and ATM, voice, and switch modules would not be recognized.
Always use this part of the show version command output to determine the feature set rather than the filename from the System image file is "flash:c3725-is-mz.122-11.T6.bin" line because it is possible that the file may have been renamed.
If a VPN module is not recognized, verify that the feature set is an IPSec version. The characters which indicate this are 56 or K. For example, (C3725-IK9S-M) or (C3640-IS56I-M) are IPSec versions.
If the feature set does not support the network module, upgrade the Cisco IOS Software to one with a compatible feature set.
For Cisco IOS Software upgrade instructions, refer to the Software Upgrade Procedure.
