Hierarchy configuration example

About the hierarchy

In this example, the ABC Corporation hierarchy is set up to direct requests of a specific type to a specific hierarchy member. ABC has three NetCache appliances, NetCache A, NetCache B, and MP3 Cache. All caches are inside a corporate firewall.

ABC hierarchy members are identified as follows:

In the hierarchy configuration of NetCache A, MP3 Cache and NetCache B are identified as parents.
In the hierarchy configuration of NetCache B and MP3 Cache, Firewall 1 is identified as a hierarchy member (firewall).

Using a hierarchy to direct requests

ABC Corporation wants to achieve the following goals:

NetCache A sends all its unresolved requests to NetCache B, which would then pass requests it could not resolve to the firewall.
All MP3 traffic is directed to one NetCache appliance, and other types of traffic are directed to a different NetCache appliance.

Configuration settings for NetCache A

This section describes how options are configured on the hierarchy configuration pages of NetCache A.

Hierarchies > General page

The following table shows the configuration on the General page.

Options on the General page	Configuration settings on NetCache A
Hierarchy Enable	Check box is selected.
Bypass Hierarchy for Noncacheable Objects	Check box is not selected.
This Domain Is Local to This NetCache Appliance	Check box is selected and the local domain is identified as abc.com.

Because "Bypass Hierarchy for Noncacheable Objects" is not selected, the NetCache predefined rule for sending requests for noncacheable objects directly to the origin server is disabled.

Hierarchies > Parents page

The following table shows how each parent is identified in the hierarchy configuration on NetCache A.

Options on the Parents page	Configuration settings for identifying MP3 Cache	Configuration settings for identifying NetCache B
Host Name	MP3 Cache	NetCache B
Ports Used by This Host	HTTP (Port 80), MMS (Port 1755), RTSP (port 554), ICP (Port 7)	HTTP (Port 80), MMS (Port 1755), RTSP (554), ICP (Port 7)
Host Supports	HTTP	HTTP
Cache Objects from This Host	Check box is selected.	Check box is selected.
Monitor Status through	HTTP	HTTP
Hierarchy Authentication	None	None

Hierarchies > Forwarding Rules page

The following tables show the hierarchy rules configured on NetCache A for forwarding MP3 requests to one NetCache appliance and forwarding all other types of requests to a different NetCache appliance.

Rule Number	Rule description
1	Send all requests for domain abc.com directly to local servers.
2	Send MP3 requests to MP3 Cache.
3	Send all other types of requests to NetCache B.

Rule 1

NetCache creates this local domain rule automatically when you select the Local Domain Enable check box on the Hierarchies - General page.

Rule 2

Rule 2 was created on the Forwarding Rules page, as shown in the following table.

Rule element	Setting on NetCache A
Rule Name (user-defined)	MP3
Rule Enable	Enabled
Protocols	None selected (rule applies to all protocols)
Conditions	Phrase: URL equals `.mp3' Note* It is not necessary to enter the beginning and ending single quotation marks when creating the rule in the Appliance Manager. You must enter beginning and ending quotation marks when you configure conditions from the CLI, however.
Distribution Method	Single Host: MP3 Cache

Rule 3

Rule 3 was created on the Forwarding Rules page, as shown in the following table.

Rule element	Setting on NetCache A
Rule name (user-defined)	Non-MP3
Rule Enable	Enabled
Protocols	None selected (This rule applies to all protocols.)
Conditions	None
Distribution Method	Single Host: NetCache B

Rule 3 is placed after the MP3 rule in the rule list so that the MP3 traffic is sent to MP3 Cache before NetCache executes the more general rule.

Configuration settings on MP3 Cache and NetCache B

The hierarchy configuration settings on both MP3 Cache and NetCache B are the same, as shown in the following tables.

Hierarchies > General page

The following table shows the configuration on the General page.

Options on the General page	Configuration settings on MP3 Cache and NetCache B
Hierarchy Enable	Check box is selected.
Bypass Hierarchy for Noncacheable Objects	Check box is not selected.
This Domain Is Local to This NetCache Appliance	Check box is selected and the local domain is identified as abc.com.

Hierarchies > Firewalls page

The following table shows the hierarchy configuration for NetCache appliances MP3 Cache and NetCache B. Neither NetCache appliance is configured to be aware of the other. The reason is that it is more efficient for MP3 Cache and NetCache B to fetch objects they do not have cached from the Internet, by way of the firewall, rather than querying the other appliance for the object.

Options on the Firewalls page	Configuration settings on MP3 Cache and NetCache B
Host Name	Firewall 1
Ports Used When Contacting This Host	HTTP (Port 80), MMS (Port 1755), RTSP (port 554), ICP (Port 7)
Host Supports	HTTP, MMS, RTSP
Cache Objects from This Host	Check box is selected.
Monitor Status through	HTTP
Hierarchy Authentication	None

Hierarchies > Forwarding Rules page

The following table describes hierarchy rules for forwarding MP3 requests to one NetCache appliance and forwarding all other types of requests to a different NetCache appliance.

Rule Number	Rule description
1	Send all requests for domain abc.com directly to the local servers.
2	Send all requests for noncacheable objects directly to the Internet.
3	Send all unresolved requests to Firewall 1.

You do not need to create custom rules on MP3 and NetCache B because NetCache enables and orders the rules in this example for you.

Rule 1:

NetCache enables its local domain rule automatically because you have enabled the Local Domain Enable option on the Hierarchies - General page.

Rule 2:

NetCache enables its noncacheable rule automatically because you have selected the "Bypass Hierarchy for Noncacheable Objects" option on the Hierarchies - General page.

Rule 3:

NetCache automatically creates protocol-specific rules to handle requests for origin servers on the Internet.