Cisco CSS 11000 Series Content Services Switches

Configuring Demand Based Replication on the CSS 11000

Document ID: 12600

Updated: Dec 27, 2007



The Content Services Switch (CSS) can track content requests, identify, and replicate hot content to overflow Web servers or caches dynamically.

When you configure demand-based replication, the CSS automatically does the following:

  • Detects hot content when the URL hits or bandwidth exceeds the configured hotlist threshold.

  • Modifies the content rules dynamically to provide additional services from where the hot content may be served.

Since the CSS is a web switch, it grabs the web page dynamically and uses FTP to copy the file to the overflow server. It then dynamically creates a rule for the content and brings the server into the load balancing pool. The CSS operates at Layer 5 (L5), and therefore, it knows which specific files are associated with a web page. The CSS does not need to replicate the entire site or branch of the web site structure.

The overflow server could be local or a redirect service elsewhere.

Before You Begin


For more information on document conventions, see the Cisco Technical Tips Conventions.


There are no specific prerequisites for this document.

Components Used

This document is not restricted to specific software and hardware versions.

The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If you are working in a live network, ensure that you understand the potential impact of any command before using it.


In this section, you are presented with the information to configure the features described in this document.

Network Diagram

This document uses the network setup shown in the diagram below.



The main, overflow, and remote overflow are HTTP servers. You need to define some content on the main server. The replication on the overflow servers is done when the threshold limit is reached.

Note: The remote overflow server does not have to be connected to the switch.

When the overflow service kicks in, note that the dynamic AUTO_Main service is dynamically created and added to the server load balancing pool for the rule. The hotlist function tracks the top ten items that are hot and creates the demand for the overflow.

CSS 11000
!Generated MAY  1 16:18:38

!Active version: ap0310029s


!*************************** GLOBAL ***************************

! The ftp-records define the userid/encrypted password to put the overflow

! data on the server's web root directory

  ftp-record PutHotData lab des-password giaxcwbsflhrh6blgnd1fyfjglfyfvf /home/httpd/html

  ftp-record PutHotData2Fast lab Des-password giaxcwbsflhrh6blgnd1fyfjglfyfvf /home/httpd/html2

!************************* INTERFACE *************************

interface ethernet-12           

!--- Create a VLAN for the remote server on Port 12.

  bridge vlan 2                 

!--- Normally the server would be at another site.

!************************** CIRCUIT **************************

circuit VLAN1

  ip address

circuit VLAN2

  ip address

!************************** SERVICE **************************

service Origin

  ip address


service Overflow

  ip address

  access ftp PutHotData 

!--- Use this record to put data on the server.

  type rep-store                

!--- Defines this service as an replica store (for example, overflow server).


service FastOverflow

  ip address

  access ftp PutHotData2Fast

  type rep-store


!*************************** OWNER ***************************


  content L5_DynaRepl

    vip address

    protocol tcp

    port 80

    add service Origin          

!--- Use this server for all URLs. If something is hot
!--- for two minutes, replicate the data and add it to the rotation.

    url "/*"                    


    hotlist threshold 2  

    add service Overflow        

  content L5_HotGraphics

    vip address

    port 80

    protocol tcp

    url "/*.gif"                

!--- Same as before, but for specific content.

    add service Origin

    add service FastOverflow


    hotlist threshold 5



Start the clients requesting 1.html. The show rule-summary command shows the dynamic content rule being added to the list of rules.

Note:  The automatic rule has "AUTO_" attached to the name of the rule that created it.

VIP Address     Port  Prot Url                CntRuleName    OwnerName  State

--------------- ----- ---- ------------------ -------------- ---------- ------      80    TCP  /*                 L5_DynaRepl    Active      80    TCP  /1.html            AUTO_L5_DynaRe    Active

Issuing the show summary command reveals that the origin server and overflow servers are both being used to serve the data. Similar to the rule, the service has "AUTO_" on the front of it to show that it was dynamically created. The show service AUTO_Overflow command shows how long the content has been replicated.

Global Bypass Counters:

   No Rule Bypass Count:     3

   Acl Bypass Count:         0

Owner            Content Rules    State     Services         Service Hits          L5_DynaRepl      Active    Origin           28401

                                            Overflow         (DBR)

                 AUTO_L5_DynaRepl Active    Origin           9073

                                            AUTO_Overflow    9074

Add the 1.gif. It will replicate to the remote server.

Note: The originating rule shows the service as having "Demand Based Replication (DBR)" hits.

Global Bypass Counters:

   No Rule Bypass Count:     5

   Acl Bypass Count:         0

Owner            Content Rules    State     Services         Service Hits          L5_DynaRepl      Active    Origin           28403

                                            Overflow         (DBR)

                 L5_HotGraphics   Active    Origin           2599

                                            FastOverflow     (DBR)

                 AUTO_L5_DynaRepl Active    Origin           10388

                                            AUTO_Overflow    10389

                 AUTO_L5_HotGraph Active    Origin           15

                                            AUTO_FastOverflo 16


There is currently no specific troubleshooting information available for this configuration.

Related Information

Updated: Dec 27, 2007
Document ID: 12600