Alignment Error 
Definition
In Cisco IOS, alignment errors occur when the software accesses valid memory locations at invalid address boundaries. This is always a software defect. These errors will be displayed on the console, in the logs and also viewable through the hidden Cisco IOS Router#show alignment EXEC command.
Alignment corrections are very CPU-intensive as such, the CPU cycles of a device experiencing alignment errors will be higher than normal - depending on the frequency of the errors and corrections.
Below is an example of the error and command output:
%ALIGN-3-CORRECT: Alignment correction made at 60EF3763 reading/writing 0x60262474
Router#show alignment
Alignment data for:
RSP Software (RSP-ISV-M), Version 12.1(7), RELEASE SOFTWARE (fc1)
Compiled Fri 18-May-01 11:34 by phanguye
Total Corrections 9, Recorded 3, Reads 9, Writes 0
Initial Initial
Address Count Access Type Traceback
60EF3765 3 32bit read 0x60262474 0x601AC594 0x601AC580
60EF3761 3 32bit read 0x60262478 0x601AC594 0x601AC580
60EF3763 3 32bit read 0x60262478 0x601AC594 0x601AC580
No spurious memory references have been recorded.
In IEEE 802.3 networks, an error that occurs when the total number of bits of a received frame is not divisible by eight. Alignment errors usually are caused by frame damage due to collisions.
Type: Networkpedia - Archive ID: 3.152 - 250 Views - Last Updated: February 18, 2009 03:49:45
Tags: alignment error bug cisco ios software