ACE4710 and compression - deflate or gzip

hugues.brunel · ‎10-15-2008

Hello,

I configure compression on a new loadbalance policy from the GUI.

GUI generate this config:

class-map type http loadbalance match-any default-compression-exclusion-mime-type

description DM generated classmap for default LB compression exclusion mime types.

2 match http url .*gif

3 match http url .*css

4 match http url .*js

5 match http url .*class

6 match http url .*jar

7 match http url .*cab

8 match http url .*txt

9 match http url .*ps

10 match http url .*vbs

11 match http url .*xsl

12 match http url .*xml

13 match http url .*pdf

14 match http url .*swf

15 match http url .*jpg

16 match http url .*jpeg

17 match http url .*jpe

18 match http url .*png

Is there a good reason to NOT compress .txt, .css, .js files?? (which are standard ASCII files)

Hugues.

sachinga.hcl · ‎10-17-2008

HI Huges,

Uncacheable data have dominated today's http traffic and multimedia type content transsferred by P2P applications and graphic types(jpg and gif) are top two in the uncacheable HTTP objects.

Compared with cacheable content, uncacheable content consumes more server processing time, but due to network latency, the client-percieved response time tends to be close to that of cacheable content.

On average uncacheable content has an larger object size than that of cacheable object.

A considerable amount of uncacheable HTTP content is cachebale.

FlashForward technology eliminates the network delays associated with embedded cacheable web objects such as images, style sheets, and JavaScript files.

So it would be of significant consideration to compress the above mentioned embedded cacheable web objects .

Text-based file sizes can also be reduced up to 80 percent if you use compression for these types also.

The Cisco ACE 4710 appliance achieves speeds up to 1 Gbps for compression. The Cisco delta encoding technology enables the Cisco ACE 4710 appliance to send only the difference (or deltas) between a previous and new instance of a webpage.

Without this technology, subsequent visits to a webpage require the client to download the entire HTML page, even though typically only a small percentage of the content has changed.

So using compression for these objects can be good upto some extent.

Regards .

Sachin Garg

Senior Specialist Security

HCL Comnet Ltd.

http://www.hclcomnet.co.in

A-10, Sector 3, Noida- 201301

INDIA

hugues.brunel · ‎10-18-2008

Thank you for your clear explanation.

Here is my new class-map:

class-map type http loadbalance match-any light-compression-exclusion-mime-type