Intel IXP400 10.3.6.3 802.3 / 802.11 API Details, 11 to 802.3 Header Conversion Rules, Frame Type

Intel® IXP400 Software

Access-Layer Components: Ethernet Database (IxEthDB) API

state so that the converted frame is treated as an untagged for the purpose of VLAN egress tagging. To simplify its processing, the NPE Ethernet firmware expects that any 802.11 frame submitted by the client will not have a VLAN tag.

Table 33. 802.11 to 802.3 Header Conversion Rules

	Input 802.11 Frame Values			Output 802.3 Frame Field Values
ixp_ne_flags	From DS(1)	Frame Type	Header Size	Destination Address	Source Address
.link_prot			(bytes)
10	0	From STA to AP	24	802.11 Address 3	802.11 Address 2
11	1	From AP to AP	39	802.11 Address 3	802.11 Address 4

(1) - The NPE does not actually inspect the From DS field to determine the 802.11 frame type. It relies exclusively on the value of the ixp_ne_flags.link_prot field.

10.3.6.3802.3 / 802.11 API Details

As mentioned previously, the IxEthDB component maintains a WiFi Header Conversion Database to store MAC address/port entries and their respective 802.3/802.11 transformation mode. There are two functions used to add these entries:

•ixEthDBWiFiStationEntryAdd() – this function takes as parameters a port ID and the MAC address of a wireless station. This function should be used for AP-STA scenarios. Up to 511 station entries are supported per port.

•ixEthDBWiFiAccessPointEntryAdd() – this functions takes port ID, MAC address of a wireless station and MAC address of the gateway Access Point as parameters. Up to 31 entries of this type may be defined per port.

Note: MAC addresses are unique database keys only within the configuration data of each port. Multiple ports can use the same MAC address entry if individually added to each port.

Additionally, three functions are provided that set the per port 802.11 Host Station Parameters, namely the BSSID (Basic Service Set ID), Frame Control and Duration/ID fields in the 802.11 frame format.

The NPE 802.3/802.11 Conversion Tables are derived from the WiFi Header Conversion Database and must be downloaded to each NPE separately, using the ixEthDBWiFiConversionTableDownload() function.

The 802.3/802.11 Frame Conversion feature introduces specific requirements on when FCS Frame Appending should be enabled. Refer to “FCS Appending” on page 179.

A typical usage scenario of this feature would consist in the following steps:

1.Enable the IX_ETH_DB_WIFI_HEADER_CONVERSION feature.

2.Add wireless station and access point/gateway addresses using ixEthDBWiFiAccessPointEntryAdd() or ixEthDBWiFiStationEntryAdd().

3.Set the 802.11 Host Station Parameters (BBSID, Frame Control, Duration/ID).

4.Download the WiFi conversion configuration data using ixEthDBWiFiConversionTableDownload(port).

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