DistributedDirector Enhancements for Cisco IOS Release 12.2(4)T3

Note Effective with Cisco IOS Release 12.4(24)T, this feature is not available in Cisco IOS software.

Feature History

Release
Modification

11.1(1)IA

Cisco DistributedDirector System Software was introduced.

11.1(25)IA

Support for DNS Mail Exchanged Records was introduced.
Policy Redirection was introduced.
Unlimited Number of IP Addresses Per Virtual Hostname was introduced.
Per-Hostname Time-to-Live was introduced.

11.1(28)IA

Enhanced Fault Tolerance with Multiple Resource Records was introduced.
Event Recording with Syslog was introduced.
Enhanced Server Verification with Multiple Port Connect Tests was introduced.

12.1(5)T

Dynamic Feedback Protocol (DFP) was introduced.
Enhanced Fault Tolerance with Multiple Resource Records was modified.
Event Recording with Syslog was modified.
Enhanced Server Verification with Multiple Port Connect Tests was modified.

12.2(4)T3

Several new commands were added.

12.4(24)T

This feature was removed.


This feature module describes four new commands and one modified command for DistributedDirector in Cisco IOS Release 12.2(4)T3. This document includes the following sections:

•Feature Overview

•Finding Feature Information

•Supported Standards, MIBs, and RFCs

•Configuration Tasks

•Configuration Examples

•Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental. © 2007 Cisco Systems, Inc. All rights reserved.

Feature Overview

Cisco DistributedDirector can use all of its decision-making metrics to determine the best server for a client request. From the configured metrics, DistributedDirector chooses the best distributed server and returns its IP address to the local Domain Name System (DNS) server for the client.

The new ip director default priorities command specifies the default priorities for each type of metric. The default priorities will take effect if no host-specific priorities are specified in the ip director host priority command or in the corresponding DNS text record. If a metric does not have a priority or a weight specified, the metric is ignored.

The new ip director drp rttprobe command sets the protocol used by Director Response Protocol (DRP) agents for round trip time (RTT) probing. The protocols to be set are the Transmission Control Protocol (TCP) and the Internet Control Message Protocol (ICMP). Both protocols can be activated, in which case DistributedDirector will instruct DRP agents to return the RTT collected from either the TCP or the ICMP, whichever becomes available first. Using the no form of the command causes DistributedDirector to stop using a specified protocol for RTT probing. At any time, one of the protocols must be activated, and both protocols can be activated if desired. The default protocol is TCP.

The new ip dns server command enables the DNS server on the router.

The new show ip director default priority command is used to verify the default priority for any metric.

The ip director default-weights command name has been modified slightly in this release. The command name is now ip director default weights.

Benefits

The ip director default priorities command sets defaults for DistributedDirector metrics.

The ip director drp rttprobe command allows users to select the protocol for RTT probing that works best for your system.

The ip dns server command allows users to activate and use the DNS server on the router.

The show ip director default priority command allows user to verify the default priority for any metric.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Supported Standards, MIBs, and RFCs

Standards

No new standards are supported by these commands.

MIBs

No new MIBs are supported by these commands.

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

No new RFCs are supported by these commands.

Configuration Tasks

See the following sections for configuration tasks for this feature.

•Configuring Default Priorities for Metrics (optional)

•Setting the Protocol Used for RTT Probing (optional)

•Enabling the DNS Server (optional)

Configuring Default Priorities for Metrics

To set a default priority for a metric, use the ip director default priorities command.

 
Command
Purpose

Step 1 

Router(config)# ip director default priorities
drp-ext 1

Sets default priorities for a specified metric. In this example, a default configuration of 1 is set for the drp-ext metric.

Step 2 

Router# copy running-config startup-config

Copies the running configuration to the startup configuration.

To remove a default priority for a metric, use the no ip director default priorities command.

 
Command
Purpose

Step 1 

Router(config)# no ip director default priorities

Removes default priorities for a specified metric.

Step 2 

Router# copy running-config startup-config

Copies the running configuration to the startup configuration.

Setting the Protocol Used for RTT Probing

To set the protocol used by DRP agents for RTT probing, use the ip director drp rttprobe command.

 
Command
Purpose

Step 1 

Router(config)# ip director drp rttprobe ICMP

Sets the protocol to be used by DRP agents for RTT probing. In this example, the protocol is ICMP.

Step 2 

Router# copy running-config startup-config

Copies the running configuration to the startup configuration.

To return to the default protocol, use the no ip director drp rttprobe command.

 
Command
Purpose

Step 1 

Router(config)# no ip director drp rttprobe ICMP

Returns the user to the default protocol for this command. The default protocol is TCP.

Step 2 

Router# copy running-config startup-config

Copies the running configuration to the startup configuration.

Enabling the DNS Server

To enable the DNS server on a router, use the ip dns server command.

 
Command
Purpose

Step 1 

Router(config)# ip dns server

Enables the DNS server on a router.

Step 2 

Router# copy running-config startup-config

Copies the running configuration to the startup configuration.

To disable the DNS server on a router and return to the default configuration, use the no ip dns server command.

 
Command
Purpose

Step 1 

Router(config)# no ip dns server

Disables the DNS server on a router.

Step 2 

Router# copy running-config startup-config

Copies the running configuration to the startup configuration.

Verifying Default Priorities for Metrics

To verify a default priority for a metric, enter the show ip director default priority command. The following example shows output from this command. 

Router# show ip director default priority


Director default metric priorities:

random priority = 2

DRP route lookup external to AS priority = 1

administrative preference priority = 0

DRP route lookup internal to AS priority = 0

DRP distance to associated server priority = 0

portion priority = 0

Round-trip time from DRP to client priority = 0

DFP originated weight priority = 0

Route-map evaluation priority = 0

Configuration Examples

This section provides the following configuration examples:

•Specifying Default Priorities for Metrics Example

•Setting the Protocol for RTT Probing Example

•Enabling the DNS Server Example

Specifying Default Priorities for Metrics Example

In the following example, a default priority of 1 is configured for the drp-ext metric, and a default priority of 2 is configured for the random metric: 

ip director default priorities drp-ext 1 random 2

Setting the Protocol for RTT Probing Example

In the following example, the command configures ICMP (in addition to the default of TCP) to be used by DRP agents for RTT probing: 

ip director drp rttprobe icmp

Enabling the DNS Server Example

In the following example, the DNS server is enabled. 

ip dns server


Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

© 2007 Cisco Systems, Inc. All rights reserved.