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.
This document is not restricted to specific software and hardware
For more information on document conventions, refer to the
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 10.10.10.1/24 and
configure the VIP range as 10.10.10.2 range 400, the CSS does not arp for any
of the addresses beyond 10.10.10.254.
However, if you configure the circuit for 10.10.10.1/24 and configure
the VIP range as 10.10.10.2 range 200, the CSS does arp for all addresses in
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.
Configure the service.
ip address 10.0.0.1 range 50
port 40000 range 50
(the range can be from 2 to 65535)
keepalive type http
keepalive method get
keepalive uri "/index.html"
(the keepalive will be sent to the first IP or port in the range)
Configure the rule with the use of a VIP range.
vip address 126.96.36.199 range 50
add service web1
add service web2
Note: Cisco does not recommend the configuration of more than 1,000
domain www.customer1.com index 1 description "aaa company"
domain www.customer2.com index 2
domain www.customer3.com index 3
domain www.customer4.com index 4
domain www.customer5.com index 5
domain www.customer6.com index 6
domain www.customer7.com index 7
domain www.customer8.com index 8
domain www.customer9.com index 9
domain www.customer10.com index 10
domain www.customer11.com index 11
domain www.customer12.com index 12
domain www.customer13.com index 13
domain www.customer14.com index 14
domain www.customer15.com index 15
domain www.customer16.com index 16
domain www.customer17.com index 17
domain www.customer18.com index 18
domain www.customer19.com index 19
domain www.customer20.com index 20
domain www.customer21.com index 21
domain www.customer22.com index 22
domain www.customer23.com index 23
domain www.customer24.com index 24
domain www.customer25.com index 25
domain www.customer26.com index 26
domain www.customer27.com index 27
domain www.customer28.com index 28
domain www.customer29.com index 29
domain www.customer30.com index 30
domain www.customer31.com index 31
domain www.customer32.com index 32
domain www.customer33.com index 33
domain www.customer34.com index 34
domain www.customer35.com index 35
domain www.customer36.com index 36
domain www.customer37.com index 37
domain www.customer38.com index 38
domain www.customer39.com index 39
domain www.customer40.com index 40
domain www.customer41.com index 41
domain www.customer42.com index 42
domain www.customer43.com index 43
domain www.customer44.com index 44
domain www.customer45.com index 45
domain www.customer46.com index 46
domain www.customer47.com index 47
domain www.customer48.com index 48
domain www.customer49.com index 49
domain www.customer50.com index 50
Configure a rule with the use of the DQL.
vip address 188.8.131.52
add service web1
add service web2