3.1 Configuring Caching Hierarchies

If several proxy servers are serving the network, you can set up a hierarchy of proxy caches. If a proxy server does not find the requested page in its cache, it queries its peers and parents for the information. The queried peers and parents can then, in turn, query additional peers and parents for the requested information. The origin server is queried as the last resort.

The Novell BorderManager proxy server is compatible with other proxy servers on the Internet that are based on the Internet Cache Protocol (ICP). You can set up these proxy servers as peers (neighbors), parents, or both.

You can configure a CERN hierarchy, a cache hierarchy (ICP), or both. If both are configured, the cache hierarchy takes precedence and the CERN hierarchy is used as a backup. CERN hierarchies have only parents, whereas cache hierarchies have both parents and peers.

This section contains the following information on caching hierarchies:

3.1.1 Configuring Cache Hierarchy Server

To configure a cache hierarchy server:

  1. Log in to iManager.

  2. Select Novell BorderManager > Proxy Services.

  3. Browse to and select the BorderManager server or container that you want to configure, then click OK.

  4. Click HTTP in the Forward Proxy section.

  5. Select the Cache Hierarchy Server tab.

  6. Select Enable Cache Hierarchy Server to enable the cache hierarchy server.

    Cache hierarchy server configuration

  7. Select Enable Source Round-Trip Time to enable proxy to use the route that returns the shortest round-trip time. This parameter is used by the proxy to determine whether to send a request to the parent or to the origin server.

  8. Select Enable ICP ACL to enable the cache hierarchy or ICP access control on the server.

  9. In the ACL Listening Port field, specify the UDP port on which the cache listens for queries from other caches.

  10. Access Control List consists of a list of hostnames or IP addresses that are used to verify whether proxies can send a request. The clients on this list are allowed to send a cache hierarchy request. You can perform one of the following actions in this section:

    New: To add a new IP address, click New, specify the hostname or IP address, then click OK.

    Delete: To delete an IP address, select the check box next to the IP address, then click Delete

  11. Multicast Group List consists of a list of multicast addresses on which the cache hierarchy server receives multicast cache hierarchy queries. You can perform one of the following actions in this section:

    New: To configure a new multicast address, click New, specify the Multicast IP address, then click OK.

    Delete: To delete a multicast IP address, select the check box next the IP address, then click Delete.

  12. Click OK.

  13. Click Apply Changes to save changes.

3.1.2 Configuring Cache Hierarchy Client

To configure a cache hierarchy client:

  1. Log in to iManager.

  2. Select Novell BorderManager > Proxy Services.

  3. Browse to and select the BorderManager server or container that you want to configure, then click OK.

  4. Click HTTP in the Forward Proxy section.

  5. Select the Cache Hierarchy client tab.

  6. Select Enable Cache Hierarchy Server to enable the cache hierarchy server.

    Cache hierarchy client configuration

  7. Select Enable Cache Hierarchy Client.

  8. Select Must Only Forward Through Hierarchy if you do not want the proxy server to retrieve the requested objects directly from the origin server.

  9. In the Cache Neighbor Timeout value field, specify the number of seconds or minutes the proxy server waits for a response to a cache hierarchy request from another proxy server.

    NOTE:Do not specify a value if you are configuring a CERN client.

  10. The Neighbor List consists of one or more neighbors for the Neighbors List, with the following information specified:

    Neighbor Hostname: Specifies the name of the nearest host server neighbor.

    Proxy Port: Port number of the neighbor HTTP proxy.

    ICP Port: Port number of the neighbor cache hierarchy client.

    NOTE:Do not specify a value if you are configuring a CERN client.

    Type: Specify the type of neighbor as peer, parent, or CERN. Select peer or parent if you are configuring a cache hierarchy client, or select CERN if you are configuring a CERN client.

    ICP Routing Priority: You can prioritize a set of parents or neighbors in a scale of 1 to 10. A cache hierarchy client chooses the fastest responding hierarchy cache with the highest priority to service a request. CERN uses pure priority routing without querying.

    Domain Restriction: Specify domains that the cache hierarchy client will serve. Click Add to add new domains or click Delete to delete existing domains.

    To add a new neighbor, click New and specify details in all the fields, then click OK.

    To delete an existing neighbor, select the check box next to the neighbor that you want to delete, then click Delete.

  11. The Multicast Responder List is a list of all acceptable neighbors (unicast) that can respond to a multicast query. This list lets the cache hierarchy client verify that the responses are from a valid neighbor. You can perform one of the following actions in this section:

    New: To add a new unicast, click New, specify the unicast name or IP address, specify a proxy port, then click OK.

    NOTE:Do not specify a value if you are configuring a CERN client.

    Delete: To delete a unicast, select the check box next to Unicast Name/Address, then click Delete.

  12. Click OK.

  13. Click Apply Changes to save changes.

3.1.3 Configuring Cache Hierarchy Routing

Use cache hierarchy routing when the parent cannot contact the origin server.

  1. Log in to iManager.

  2. Select Novell BorderManager > Proxy Services.

  3. Browse to and select the BorderManager server or container that you want to configure, then click OK.

  4. Click HTTP in the Forward Proxy section.

  5. Select the Cache Hierarchy Routing tab.

    Cache hierarchy routing configuration

  6. The Local Domain List consists of a list of local domain names for origin Web servers that are in close proximity. The proxy server prefers to query for a URL that it cannot resolve from these servers instead of from the cache hierarchy. You can perform one of the following actions in this section:

    New: To add a new domain name to the Local Domain list, click New, specify a domain name, then click OK.

    Delete: To delete a domain, select the check box next to the domain name, then click Delete.

  7. The Pattern Stop List consists of a list of one or more stop patterns for which the cache must query the origin Web server directly. Specify patterns for which the delays caused by hierarchical caching are unacceptable, for example, static pages that change frequently. You can perform one of the following actions in this section:

    New: To add a new pattern to the list, click New, specify a pattern name, then click OK.

    Delete: To delete a pattern, select the check box next to the pattern, then click Delete.

  8. Click OK.

  9. Click Apply Changes to save changes.