Cisco Application Control Engine (ACE) Troubleshooting Guide -- Troubleshooting Compression
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This article describes the process and CLI commands for troubleshooting compression in the ACE.
Contents |
Overview of Compression
Compression is supported on the ACE30 module running software version A4(1.x) and later and on the ACE 4700 series appliance (all software releases). You can configure compression by entering the compress command under a Layer 7 load-balancing policy. For example:
class-map type http loadbalance match-any L7default-compression- exclusion-mime-type_CLASS
description Classmap for default SLB compression exclusion mime-types.
2 match http url .*gif
3 match http url .*css
4 match http url .*js
policy-map type loadbalance first-match L7_COMP_SLB_POLICY
class L7default-compression-exclusion-mime-type_CLASS
serverfarm SFARM1
class class-default
serverfarm SFARM1
compress default-method deflate <--------------------------- Configured compression method
interface vlan 200
service-policy L7_COMP_SLB_POLICY
no shutdown
For compression to work, a client must send a request with an ACCEPT-ENCODING method of gzip or deflate. If a client sends both methods, then the ACE uses the configured method. The ACE rewrites the ACCEPT-ENCODING header to IDENTITY to indicate to the server that it should not compress the return data. By default, the ACE does not compress responses that are less than 512 bytes. You can change this minimum size threshold by using an HTTP parameter-map as follows:
parameter-map type http HTTP_PARAMMAP compress minimum-size 100
The ACE does not compress the server response if the response contains HTTP/1.0, HTTP responses other than 200 OK and 100 Continue, and the following:
- cache-control: not transform
- content-MD5
You can configure various others parameters using an HTTP parameter map (for example, mimetype and user-Agent).
Troubleshooting Compression
To display compression statistics, enter the following command:
switch/Admin# show service-policy L7_COMP_SLB_POLICY detail
Status : ACTIVE
Description: -----------------------------------------
Interface: vlan 1 108
service-policy: L7_COMP_SLB_POLICY
class: vip
VIP Address: Protocol: Port:
2.0.5.1 tcp eq 80
loadbalance:
L7 loadbalance policy: pm
VIP ICMP Reply : ENABLED
VIP state: OUTOFSERVICE
Persistence Rebalance: ENABLED
curr conns : 0 , hit count : 0
dropped conns : 0
client pkt count : 0 , client byte count: 0
server pkt count : 0 , server byte count: 0
conn-rate-limit : 0 , drop-count : 0
bandwidth-rate-limit : 0 , drop-count : 0
L7 Loadbalance policy : pm
class/match : h
ssl-proxy client : c
LB action :
primary serverfarm: sf1
state: DOWN
backup serverfarm : -
hit count : 0
dropped conns : 0
compression : on <------------------------------ Compression is enabled if the value is "on"
compression:
bytes_in : 0 bytes_out : 0 <--- Number of bytes transmitted after compressing the server response
Compression ratio : 0.00% <------------------------------ Percentage of data compressed
Gzip: 0 Deflate: 0 <--------------- Number of times the method is used
compression errors: _
User-Agent : 0 Accept-Encoding : 0 |
Content size: 0 Content type : 0 |
Not HTTP 1.1: 0 HTTP response error: 0 |-- Check these error counters to see if they are increasing
Others : 0 |
Parameter-map(s): _|
