I have a Cisco 1841 that has 8 VPN's running through it (it is not the tunnel endpoints though), it also provides internet access for the main office through a 10 Mb leased line.
It keeps crashing every few days with this appearing in the Syslog :
2008-10-06 09:00:14 Local7.Critical 212.240.x.x 50: Pool: Processor Free: 206548 Cause: Memory fragmentation
2008-10-06 09:00:14 Local7.Critical 212.240.x.x 51: Alternate Pool: None Free: 0 Cause: No Alternate pool
2008-10-06 09:00:14 Local7.Critical 212.240.x.x 52:
2008-10-06 09:00:14 Local7.Critical 212.240.x.x 53: -Process= "ARP Input", ipl= 3, pid= 10
2008-10-06 09:00:14 Local7.Critical 212.240.x.x 54: -Traceback= 0x608DD040 0x601FBB28 0x60200C38 0x6021A5CC 0x60245E38 0x602466D8 0x60246960 0x60A63A3C 0x60A69720 0x60A6D4A4 0x60A6DB3C 0x60696374 0x60A9529C 0x60C0F518 0x60C0FB24 0x60C10614
2008-10-06 09:00:14 Local7.Critical 212.240.x.x 49: 000046: *Oct 6 08:03:50: %SYS-2-MALLOCFAIL: Memory allocation of 65536 bytes failed from 0x6021A5C4, alignment 16
2008-10-06 09:00:15 Local7.Error 212.240.x.x 55: 000047: *Oct 6 08:03:50: %FIB-3-NOMEM: Malloc Failure, disabling CEF
2008-10-06 09:00:15 Local7.Error 212.240.x.x 56: -Traceback= 0x608DD040 0x60A63AA4 0x60A69720 0x60A6D4A4 0x60A6DB3C 0x60696374 0x60A9529C 0x60C0F518 0x60C0FB24 0x60C10614 0x606A3AF0
2008-10-06 09:05:29 Local7.Error 212.240.x.x 61: 000052: *Oct 6 08:09:02: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
From what I have read, this error normally indicates that the Processor pool is running out of memory - I have tried 'memory-size iomem 5' but it still keeps crashing.
I have also swapped the router with a different one (1812) and upgraded the firmware - still the same result. If i disable CEF it lasts a week before it crashes, this time with nothing in the syslog.
I am now looking to upgrade the internal memory - will this fix the problem ?