Here are few syslog messages in a cisco switch.Each syslog message has common parameters like Facility, Severity & Mnemomics.

%SYS-5-CONFIG_I: Configured from console by consol
%STACKMGR-4-SWITCH_ADDED: Switch 1 has been ADDED to the stack
%LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
%SPANTREE-5-EXTENDED_SYSID: Extended SysId enabled for type vlan

You can send these syslog messages to a Console, buffer, monitor, host depend on your requirement. Most common is sending to a remote host (or syslog server). For troubleshooting you can configure a device to send it to console or monitor (if you remotely log in) or buffer.  Following example shows syslog configuration done on a cisco IOS device.

logging facility local5
logging buffered 100000 notification
logging trap notifications
logging source-interface Loopback0

There are 8 severity levels in Syslog messages. Once you configured a severity level all syslog messages from that level & below (numerical value) messages are sent to syslog server.

0- Emergency
1 – Alert
2 – Critical
3 – Error
4 – Warning
5 – Notification
6 – Informational
7 – Debugging
I remember this using “Every Airplane comes with Critical Errors & Warning Notification Information Display”.

To configure syslog in cisco WLC you have to go “Management > Logs > Config” section. Syslog level show in the drop-down box is not in to severity order you have to know severity number against each classification. e.g if they ask to configure severity level 3 & above, you have to select ” Error” here. Syslog facility level can be used to differentiate syslog messages coming from a certain devices. e.g. you can configure all routers syslog to certain facility level & all switches syslog in another facility level.


Also you can configure message logs to store local to the controller in the same section. You can configure buffer & console log levels. By using CLI as well you can configure those. Following shows the available options for configuration.

(WLC1) >config logging ?        

buffered       Set buffered logging parameters.
console        Set console logging parameters.
debug          Set debug message logging parameters.
exception      Limit size of exception flush output.
fileinfo       Set source file information logging parameters.
syslog         Configure parameters for outgoing syslog mesages.
traceinfo      Set traceback information logging parameters.

By using the WLC CLI you can configure advanced options for Syslog. Below shows advanced config options available for a particular frequency band (in this case 802.11a or  5GHz)

(WLC1) >show advanced 802.11a logging 
RF Event and Performance Logging
  Channel Update Logging......................... Off
  Coverage Profile Logging....................... Off
  Foreign Profile Logging........................ Off
  Load Profile Logging........................... Off
  Noise Profile Logging.......................... Off
  Performance Profile Logging.................... Off
  TxPower Update Logging......................... Off

You can configure any of these by “config advanced <802.11a|802.11b> logging < > <on|off> “command. As you can see above all are off by default.

(WLC1) >config advanced 802.11a logging ?        
channel        802.11a channel change logging mode.
coverage       802.11a coverage profile logging mode.
foreign        802.11a foreign interference profile logging mode.
load           802.11a load profile logging mode.
noise          802.11a noise profile logging mode.
performance    802.11a performance profile logging mode.
txpower        802.11a transmit power change logging mode.

(WLC1) >config advanced 802.11a logging channel ?              
on             Turns on 802.11a channel logging
off            Turns off 802.11a channel logging

Access Points related syslog messages can be configured only using CLI mode. You can configure getting syslog from all ap (global) or from specific ap (specific) by using “config ap syslog host ” command.

(WLC1) >config ap syslog host ?
global         Configures the global system logging host for all Cisco AP
specific       Configures the system logging host for a specific Cisco AP.
(WLC1) >config ap syslog host specific HQ-AP1

You can go through “Cisco Wireless LAN Controller Command Reference, Release 7.0” for all commands available in 7.0 release which is tested at CCIEW 2.0 lab exam.