openSolaris 2008 - Modifying DA Advertising and Discovery Frequency - System Administration Guide: Network Services

Modifying DA Advertising and Discovery Frequency

In situations such as the following, you can modify properties that control the timing of DA advertisements and discovery requests.

When you want the SA or UA to obtain DA configuration information statically from the net.slp.DAAddresses property in the slp.conf file, you can disable DA discovery.
When the network is subject to recurrent partitioning, you can change the frequency of passive advertisements and active discovery.
If UA and SA clients access DAs on the other side of a dial-up connection, you can decrease the DA heartbeat frequency and the active discovery interval to reduce the number of times a dial-up line is activated.
If network congestion is high, you can limit multicasting.

The procedures in this section explain how to modify the following properties.

Table 9-2 DA Advertisement Timing and Discovery Request Properties

Property	Description
`net.slp.passiveDADetection`	Boolean that specifies whether `slpd` listens for unsolicited DA advertisements
`net.slp.DAActiveDiscoveryInterval`	Value that specifies how often `slpd` performs active DA discovery for a new DA
`net.slp.DAHeartBeat`	Value that specifies how often a DA multicasts an unsolicited DA advertisement

Limiting UAs and SAs to Statically Configured DAs

Sometimes you might need to limit UAs and SAs to obtaining DA addresses from the static configuration information in the slp.conf file. In the next procedure, you can modify two properties that cause slpd to obtain DA information exclusively from the net.slp.DAAddresses property.

How to Limit UAs and SAs to Statically Configured DAs

Use the following procedure to change the net.slp.passiveDADetection and the net.slp.DAActiveDiscoveryInterval properties.

Note - Use this procedure only on hosts that execute UAs and SAs which are restricted to static configurations.

Become superuser or assume an equivalent role.
Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services. To configure a role with the Primary Administrator profile, see Chapter 2, Working With the Solaris Management Console (Tasks), in System Administration Guide: Basic Administration.
Stop slpd and all SLP activity on the host.
```
# svcadm disable network/slp
```
Back up the default /etc/inet/slp.conf file before you change the configuration settings.
Set the net.slp.passiveDADetection property to False in the slp.conf file to disable passive discovery. This setting causes slpd to ignore unsolicited DA advertisements.
```
net.slp.passiveDADetection=False
```
Set the net.slp.DAActiveDiscoveryInterval to -1 to disable initial and periodic active discovery.
```
net.slp.DAActiveDiscoveryInterval=-1
```
Save your changes and close the file.
Restart slpd to activate your changes.
```
# svcadm enable network/slp
```

Configuring DA Discovery for Dial-up Networks

If the UAs or SAs are separated from the DA by a dial-up network, you can configure DA discovery to reduce or eliminate the number of discovery requests and DA advertisements. Dial-up networks usually incur a charge when activated. Minimizing extraneous calls can reduce the cost of using the dial-up network.

Note - You can disable DA discovery completely with the method that is described in Limiting UAs and SAs to Statically Configured DAs.

How to Configure DA Discovery for Dial-up Networks

You can use the following procedure to reduce unsolicited DA advertisements and active discovery by increasing the DA heartbeat period and the active discovery interval.

Become superuser or assume an equivalent role.
Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services. To configure a role with the Primary Administrator profile, see Chapter 2, Working With the Solaris Management Console (Tasks), in System Administration Guide: Basic Administration.
Stop slpd and all SLP activity on the host.
```
# svcadm disable network/slp
```
Back up the default /etc/inet/slp.conf file before you change the configuration settings.
Increase the net.slp.DAHeartbeat property in the slpd.conf file.
```
net.slp.DAHeartbeat=value
```
value

A 32-bit integer that sets the number of seconds for the passive DA advertisement heartbeat
Default Value=10800 seconds (3 hours)
Range of Values=2000–259200000 seconds

For example, you can set the DA heartbeat to approximately 18 hours on a host that is executing a DA:
```
net.slp.DAHeartbeat=65535
```
Increase the net.slp.DAActiveDiscoveryInterval property in the slpd.conf file:
```
net.slp.DAActiveDiscoveryInterval value
```
value

A 32–bit integer that sets the number of seconds for DA active discovery queries
Default Value=900 seconds (15 minutes)
Range of Values=300–10800 seconds

For example, you can set the DA active discovery interval to 18 hours on a host that is executing a UA and an SA:
```
net.slp.DAActiveDiscoveryInterval=65535
```
Save your changes and close the file.
Restart slpd to activate your changes.
```
# svcadm enable network/slp
```

Configuring the DA Heartbeat for Frequent Partitions

SAs are required to register with all DAs that support their scopes. A DA can appear after slpd has performed active discovery. If the DA supports slpd scopes, the SLP daemon registers all advertisements on its host with the DA.

One way slpd discovers DAs is by the initial unsolicited advertisement a DA sends when it boots. The SLP daemon uses the periodic unsolicited advertisement (the heartbeat) to determine whether a DA is still active. If the heartbeat fails to appear, the daemon removes the DAs the daemon uses and those the daemon offers to UAs.

Finally, when a DA undergoes a controlled shutdown, it transmits a special DA advertisement that informs listening SA services that it will be out of service. The SLP daemon also uses this advertisement to remove inactive DAs from the cache.

If your network is subject to frequent partitions and SAs are long-lived, slpd can remove cached DAs during the partitioning if heartbeat advertisements are not received. By decreasing the heartbeat time, you can decrease the delay before a deactivated DA is restored to the cache after the partition is repaired.

How to Configure DA Heartbeat for Frequent Partitions

Use the following procedure to change the net.slp.DAHeartBeat property to decrease the DA heartbeat period.

Note - If DA discovery is completely disabled, the net.slp.DAAddresses property must be set in slp.conf on the hosts that are executing UAs and SAs so that they access the correct DA.

Become superuser or assume an equivalent role.
Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services. To configure a role with the Primary Administrator profile, see Chapter 2, Working With the Solaris Management Console (Tasks), in System Administration Guide: Basic Administration.
Stop slpd and all SLP activity on the host.
```
# svcadm disable network/slp
```
Back up the default /etc/inet/slp.conf file before you change the configuration settings.
Decrease the net.slp.DAHeartBeat value to 1 hour (3600 seconds). By default, the DA heartbeat period is set to 3 hours (10800 seconds).
```
net.slp.DAHeartBeat=3600
```
Save your changes and close the file.
Restart slpd to activate your changes.
```
# svcadm enable network/slp
```

Relieving Network Congestion

If network congestion is high, you can limit the amount of multicast activity. If DAs have not already been deployed in the network, deploying DAs can drastically reduce the amount of SLP-related multicast.

However, even after DAs are deployed, multicast is still necessary for DA discovery. You can reduce the amount of multicast necessary for DA discovery by using the method that is described in How to Configure DA Discovery for Dial-up Networks. You can completely eliminate multicast for DA discovery by using the method that is described in Limiting UAs and SAs to Statically Configured DAs.