Cisco CSS 11000 Series Content Services Switches

Virtual Web Hosting Application Guide

Document ID: 3835

Updated: Jan 31, 2006



Due to the number of ISPs that provide web hosting services to their customers, there is a need to support hundreds to thousands of virtual web sites on relatively few web servers. Virtual Web Hosting Applications extend past the ISP and into the market place. Some Web Vendors use Domain Names as search engines or to categorize the streaming media.

The basic concept is that the web-hoster has a few machines, typically from two to ten, that mirror the content. Each machine has hundreds to thousands of sites on it. The servers determine which site is requested based on the IP address, port, or Domain Name. When you try to load balance such a site, the load balancer must be able to configure with many services and virtual IP addresses or Domain Names.

Cisco has developed a solution for the need to provide this type of service. The Virtual Web Hosting Software allows the web hoster to configure a service with either a range of IP addresses or a range of ports. A content rule with either a range of VIPs or a list of Domain Names is configured to map to the servers. A content rule with a range or a list can map to a server without a range. This allows a many-to-one mapping.



There are no specific requirements for this document.

Components Used

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


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


When you configure the VIP and service ranges, Cisco recommends that you stay within the subnet that you use. The CSS does not arp for IP addresses that are not on the subnet of the circuit.

For example, if you configure the circuit for and configure the VIP range as range 400, the CSS does not arp for any of the addresses beyond

However, if you configure the circuit for and configure the VIP range as range 200, the CSS does arp for all addresses in the range.

For large VIP ranges, Cisco recommends that you have the upstream router advertise a route through the CSS to the VIP subnets in order to prevent arp storms and excessive failover times with redundancy.

This diagram provides an example:


Configure the CSS with four content rules, one for each VIP range, and four services for each server in order to prevent issues with network numbers and subnet broadcast numbers (0 and 255).

In order to prevent issues with arp storms, it is best to configure the upstream router to route all of the VIP addresses to the CSS. If you configure the VIP ranges on the same subnet as the circuit, the CSS does arp for them. Also, when you have a large number of VIPs, it takes a long period of time for redundancy to take effect.

The CSS can be configured to advertise the routes to the VIPs.

Note: You can only configure local services with ranges and add to content rules with ranges.

  1. Configure the service.

    service web1
    ip address range 50
    port 40000 range 50
    (the range can be from 2 to 65535)
    protocol tcp
    keepalive type http
    keepalive method get
    keepalive uri "/index.html"
    (the keepalive will be sent to the first IP or port in the range)
  2. Configure the rule with the use of a VIP range.

    owner virtual_sites
    content virtual_rule
    vip address range 50
    port 80
    protocol tcp
    add service web1
    add service web2
  3. Configure DQLs.

    Note:  Cisco does not recommend the configuration of more than 1,000 domain names.

    dql my_domains
    domain index 1 description "aaa company"
    domain index 2
    domain index 3
    domain index 4
    domain index 5
    domain index 6
    domain index 7
    domain index 8
    domain index 9
    domain index 10
    domain index 11
    domain index 12
    domain index 13
    domain index 14
    domain index 15
    domain index 16
    domain index 17
    domain index 18
    domain index 19
    domain index 20
    domain index 21
    domain index 22
    domain index 23
    domain index 24
    domain index 25
    domain index 26
    domain index 27
    domain index 28
    domain index 29
    domain index 30
    domain index 31
    domain index 32
    domain index 33
    domain index 34
    domain index 35
    domain index 36
    domain index 37
    domain index 38
    domain index 39
    domain index 40
    domain index 41
    domain index 42
    domain index 43
    domain index 44
    domain index 45
    domain index 46
    domain index 47
    domain index 48
    domain index 49
    domain index 50
  4. Configure a rule with the use of the DQL.

    owner virtual_sites
    content virtual_rule
    dql my_domains
    vip address
    port 80
    protocol tcp
    add service web1
    add service web2

Related Information

Updated: Jan 31, 2006
Document ID: 3835