Intel IXP400 manual Frame Size Filtering, Record Management, Database Maintenance

Intel® IXP400 Software

Access-Layer Components: Ethernet Database (IxEthDB) API

address entries and can expire older entries as appropriate. This is tied into the database maintenance functionality, further documented in “Database Maintenance” on page 160. When a record age exceeds the IX_ETH_DB_LEARNING_ENTRY_AGE_TIME definition, the record will be removed at the next maintenance interval.

IX_ETH_DB_LEARNING_ENTRY_AGE_TIME is 15 minutes by default, but may be changed as appropriate.

The aging of entries in handled first in the XScale Learning/Filtering Database and propagated to the NPE Learning/Filtering Trees.

Static entries provisioned using the IxEthDB API are not subject to aging. Provisioned entries that are defined as dynamic (ixEthDBFilteringDynamicEntryProvision ()) are subject to aging.

Note: Entries age only if their ingress port is explicitly configured to do so using the ixEthDBPortAgingEnable() function.

Record Management

The IxEthDB component contains functions for managing records in its various databases. Capabilities specific to the MAC Address Learning/Filtering facility include:

•Add static or dynamic records.

•Remove records.

•Search for a given MAC address, with the option to reset the aging value in the record.

•Displaying the database contents, grouped by port.

Database Maintenance

Maintenance is required to facilitate the aging of entries in the XScale Learning/Filtering Database and NPE Learning/Filtering Trees.

The IxEthDB component performs all database maintenance functions. To facilitate this, the ixEthDBDatabaseMaintenance() function must be called with a frequency of IX_ETH_DB_MAINTENANCE_TIME. It is the client’s responsibility to ensure the ixEthDBDatabaseMaintenance() function is executed with the required frequency. The default value of IX_ETH_DB_MAINTENANCE_TIME is one minute.

If the maintenance function is not called, then the aging function will not run. An entry will be aged at IX_ETH_DB_LEARNING_ENTRY_AGE_TIME +/- IX_ETH_DB_MAINTENANCE_TIME seconds.

10.3.2Frame Size Filtering

The API provides the ability to set the maximum size of Ethernet frames supported per port, using the ixEthDBFilteringPortMaximumFrameSizeSet() function. When a maximum frame size value is set for a port, there are multiple effects:

•Any incoming (Rx) frames on the specified port larger than the set value will be dropped. No learning will further processing will be done on this frame.

•In the Transmit data path, the NPE will check the size of an Ethernet frame during the final stage of processing the frame, just prior to transmission. If the NPE adds data (VLAN tag or

April 2005	IXP400 Software Version 2.0	Programmer’s Guide
160	Document Number: 252539, Revision: 007