Applies To:

Show Versions Show Versions

Manual Chapter: Configuring Connections Rules
Manual Chapter
Table of Contents   |   << Previous Chapter   |   Next Chapter >>

12 
The WebAccelerator system uses these connections to process requests for content. By default, the WebAccelerator system creates or reuses connections to the origin web servers as needed to service client requests as efficiently as possible. However, because sites often use a pool of web or application servers, this default behavior may not be appropriate. For example, if for your site, the same physical origin or application server must handle all of the requests received for a given session, then you must specify appropriate connections rules and associated connection mapping for the WebAccelerator system to manage these connections.
The connection settings that you specify for connections rules only apply to connections that the WebAccelerator system uses for requests. When you configure connections rules for a node, the WebAccelerator systems uses those settings only when handling requests that match the node. Connections rules are not relevant to responses that match a node.
You organize connection rules in the Policy Tree, with any associated connections rules assigned to the leaf node. The WebAccelerator system applies connections rules only against leaf nodes in the Policy Tree. The Policy Tree is described in Chapter 4, Introducing the Policy Tree.
Each leaf node in the Policy Tree has one connections rule defined for it. This rule identifies the connection type that the WebAccelerator system uses for requests that map to a specified node in the hierarchy. The connections rules connection type only applies when the WebAccelerator system sends a request to the origin web server for fresh content.
Connections rules are inherited from a parent node in their entirety. Unlike other acceleration rules, where you can add or remove parameters to existing rules, you cannot edit existing connections rules, you can only override them.
Regardless of the type of connection you choose, the WebAccelerator system creates new connections to the origin web servers only when it needs them, and the WebAccelerator system needs connections to the origin web servers only when it sends a request to the origin web servers for content.
The default connection type option provides no mapping between the client connections and the WebAccelerator systems origin web server connections.
When you select this option, the WebAccelerator system creates a single pool of connections to communicate with the origin web servers. The WebAccelerator system reuses connections from this pool to service new client connections for which it must request new content from the origin web server.
The one-to-one connection mapping option provides a unique connection to the origin web server for each unique client connection.
When you select one-to-one connection mapping, the WebAccelerator system sends a request to the origin web server for fresh content for a request, and creates a unique connection for the purpose of servicing the requests coming from that client connection. Because most browsers create two connections when browsing a site, it is likely that the WebAccelerator system will create two or more unique connections to the origin web server for each client.
When the client receives the response and drops the connection to the WebAccelerator system, the WebAccelerator system drops the corresponding connection to the origin web servers. If the client subsequently reconnects to the WebAccelerator system, the WebAccelerator system creates, as needed, a new connection to the origin web server.
Authenticated (NTLM) connections require one-to-one connection mapping and all NTLM-authenticated connections use one-to-one connections by default. One-to-one connection mapping is the most secure connection type, but it is also the slowest mapping option.
The request-based connection pool mapping option allows you to pool and reuse origin web server connections to service multiple client connections.
When you select request-based connection pool mapping, the WebAccelerator system maps connections in a pool to a request, based on the elements it finds in the request. By specifying the elements in a request that the WebAccelerator system should use to map to a connection, you ensure that all requests with certain parameters are always mapped to a particular origin web server.
Request-based connection pool mapping is most useful if you want the WebAccelerator system to send all session traffic to the same origin web server in a pool of servers, for your site. For example, if your application server sets a cookie that carries information about the origin web server, such as server ID, and you want all future requests with that same cookie value sent to the same application server, you can create a connections rule with the request-based connection pool mapping option and base its parameters on that particular cookie. This connections rule prompts the WebAccelerator system to send requests to the specified application server.
Note: Request-based connections are optimized for situations where the WebAccelerator system uses relatively few distinct request values to determine which connection to use, such as connections based on server IDs. For other types of requests, such as those based on session IDs, you get better performance using one-to-one connection mapping instead of request-based connection pool mapping.
To create a request-based connection pool mapping rule, you specify the parameter that the WebAccelerator system should look for in a request, and the value it must have for it to match to the rule. You also specify the WebAccelerator system connection behavior if the request matches the rule.
If a request element matches parameters in two or more connections rules, the WebAccelerator system takes the union of the matching parameter values to determine which connection pool to use. If the rules that match specify different pool behavior (one indicates using the same pool and the other indicates using a unique pool), the WebAccelerator system uses a unique connection pool.
A value group is a collection of rule parameter values. The purpose of a value group is to enable you to specify several different parameter values for the same rule. Each parameter value can prompt a different behavior by the WebAccelerator system. When configuring a connections rule with request-based connection pool mapping, you can specify a value group, rather than a single value for each connections rule parameter.
For example, when you configure a connections rule based on a cookie, you can only specify a single set of values for the cookie, and whether there is a match or not a match. On the other hand, if you use a request-based connection pool mapping rule, you can specify a value group for a cookie, such as sessionID.
You can use the flexibility of the value group to easily specify different behaviors for different values. In this example, there is a site that has three application servers with session IDs, where each session ID begins with a specific application server numerical ID, followed by a period and a session number, as shown in the following example:
1.AA0B3Ef72l
2.H86jT2i284K
3.b31u40FNLsms
When the cookie sessionID begins with 1., use a unique connection pool.
When the cookie sessionID begins with 2., use a unique connection pool.
When the cookie sessionID begins with 3., use a unique connection pool.
When the cookie sessionID contains any other value, use the same connection pool.
With this connections rule and associated value groups, the WebAccelerator system uses a specific connection pool to send requests that contain a sessionID cookie that begins with 1. to application server 1. The WebAccelerator system also uses unique connection pools for requests where the sessionID cookie begins with 2., and 3. to send those requests to application server 2 and 3, respectively. For all other requests, where the sessionID cookie value does not represent a valid application server, the WebAccelerator system uses a single connection pool.
1.
On the Main tab of the navigation pane, expand WebAccelerator and click Applications.
The Applications screen opens in a new window.
2.
On the Main tab of the navigation pane in the new window, click Policies.
The Policies screen opens, displaying a table of user-defined and pre-defined acceleration policies.
3.
On the User-defined Acceleration Policies table, click the name of the acceleration policy that you want to edit.
The Policy Editor screen opens.
5.
From the Matching Rules list on the Policy Editor menu bar, select Acceleration Rules.
The acceleration rules display on the Policy Editor menu bar.
6.
On the Policy Editor menu bar, click Connections.
The Connections Rules screen opens.
7.
Click the button next to Request-based connection pool mapping.
The screen refreshes, displaying the Connection Mapping Criteria area.
8.
From the Add Parameter list, select an HTTP request data type parameter, and click the Add button.
The Parameter Identity screen opens.
10.
Click the Save button.
This section of the chapter provides information about how to configure an example connections rule. For this example site, you have three top-level nodes in the Policy Tree as follows:
Home
This branch node specifies the rules related to the home page.
Applications
This branch node specifies the rules related to the applications for the site, with the following leaf nodes:
Default
This leaf node specifies the rules related to non-search related applications.
Search
This leaf node specifies the rules related to your sites search application.
Images
This branch node specifies the rules related to graphics images.
Note: See To create the Home, Application, and Images nodes for the example Policy Tree, for specific instructions about how to create the Policy Tree.
For this example, your site uses session IDs (in the form of a cookie called sessionID) to ensure that all requests in a given session are sent to the same origin web server. All requests for images from your site are sent to a specific origin web server identified by a unique subdomain, regardless of the session ID information.
For this site, you want to add identical connections rules to your Applications node and another to your Home node that specify a one-to-one connection mapping. The WebAccelerator system sends all requests for image data to the image server because of the domain information that appears on those requests, therefore, you do not have to configure a connections rule for the Images node because the default connection type is appropriate.
1.
On the Main tab of the navigation pane, expand WebAccelerator and click Applications.
The Applications screen opens in a new window.
2.
On the Main tab of the navigation pane in the new window, click Policies.
The Policies screen opens, displaying a table of user-defined and pre-defined acceleration policies.
3.
On the User-defined Acceleration Policies table, click the name of the acceleration policy that you want to edit.
The Policy Editor screen opens.
4.
5.
From the Matching Rules list on the Policy Editor menu bar, select Acceleration Rules.
The acceleration rules display on the Policy Editor menu bar.
6.
On the Policy Editor menu bar, click Connections.
The Connections Rules screen opens.
7.
Click the button next to One-to-one connection mapping.
8.
Click the Save button.
A confirmation page displays the new setting configuration.

Was this resource helpful in solving your issue?




NOTE: Please do not provide personal information.



Incorrect answer. Please try again: Please enter the words to the right: Please enter the numbers you hear:

Additional Comments (optional)