Cisco ACE Compression problem

[kashman37]

hello guys,

I have an issue with compression on Cisco ACE. Basically i turn on compression for a certain site and i browse the site to get statistics i am using httpwatch program  to get my statistics. after that i disable compression on Cisco ACE and i turn on compression on IIS7 and i take a measurement again. I compare the two measurements and i find that IIS7 compression is a lot more than Cisco ACE. The Compression used on ACE is gzip and i am using a basic configuration. does anyone know if i am doing something wrong or if i have to enable something else in order for ACE to compress more.

Thank you.

Note. On ACE i can see the compression and its high around 70% but on httpwatch the http compression that i see is a lot less.

policy-map type loadbalance first-match xxxxxxxx

  class class-default
    compress default-method gzip
    sticky-serverfarm sourcestickyxxxxx

    ssl-proxy client MOSS-SSL-CLIENT 

    class: Moss-VIP-443
      ssl-proxy server: MOSS-CISCO-SSL-PROXY
      loadbalance:
        L7 loadbalance policy: L7_SLB_Moss_443
        VIP ICMP Reply       : ENABLED
        VIP State: INSERVICE
        Persistence Rebalance: ENABLED
        curr conns       : 4         , hit count        : 365      
        dropped conns    : 1        
        client pkt count : 15947     , client byte count: 2840791            
        server pkt count : 23589     , server byte count: 28353999           
        conn-rate-limit      : 0         , drop-count : 0        
        bandwidth-rate-limit : 0         , drop-count : 0        
      compression:
        bytes_in  : 13887551           
        bytes_out : 3980315            
        Compression ratio : 71.33%
        Parameter-map(s):
          REBALANCE-MOSS

[Francesco Casotto]

Hello,

just some thoughts on the subject:

-  how is httpwatch measuring the compression? Is is per request or is it  an average calculated over multiple http requests (maybe all the ones  used to get one webpage completely)?

I ask because ACE is not  applying the compression to all the responses by default, it uses some  configurable criterias to select the ones to compress:

http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/ace_appliances/vA3_2_7/configuration/slb/guide/classlb.html#wp1581123

and these could bring the compression rate down if it's calculated averaging multiple requests, some potentially uncompressed.

- which compression algorithm is IIS 7 using?

On a general note I think that a webserver when it comes to compression may afford to push a bit more on the compression level (gzip compression rate is controlled by a parameter attempting to trade computation speed for compression) as it could then cache the compressed content (IIS 7 does it) so that not every response would have to get independently compressed on the fly as the ACE has to do.

Hope it helps,

Francesco