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IXP400 Software
Access-Layer Components: Ethernet Database (IxEthDB) API
April 2005 IXP400 Software Version 2.0 Programmer’s Guide
176 Document Number: 252539, Revision: 007
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.
10.3.6.3 802.3 / 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).
Table 33. 802.11 to 802.3 Header Conversion Rules
Input 802.11 Frame Values Output 802.3 Frame Field Values
ixp_ne_flags
.link_prot
From DS
(1)
Frame Type
Header Size
(bytes)
Destination Address Source Address
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.