________________________________________________ DS33X162/X161/X82/X81/X42/X41/X11/W41/W11
Rev: 063008
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3. Select the appropriate FIFO for insertion via GL.MCR1.
4. Write the size of frame in bytes to GL.MCR3 for LAN insertion, GL.MCR2 for WAN insertion.
5. Write the frame to the GL.MFAWR.WPKT[0:7], one byte at a time.
7. Repeat Step 1.
Frames loaded into the WAN Insertion FIFO should not include the GFP Length and cHEC fields. Inserted frames
should include all other applicable GFP/HDLC header information and a valid HECs. The header information on
inserted frames may be different than the header of normal traffic to allow for a number of management protocols
to be present on the link. The only modifications made by the device to data placed in the WAN Insertion queue are
the addition of the GFP Length/cHEC, the line coding functions of bit/byte stuffing, and X
43+1 scrambling, if
enabled.
Frames loaded into the LAN Insertion FIFO should be complete and valid IEEE 802.3 or DIX Ethernet frames. If the
frame should not contain an Ethernet FCS. The frame loaded into the insertion FIFO should not contain a preamble
or start frame delimiter, as these will be automatically added by the MAC. Frames inserted to the LAN do not pass
through a Decapsulator.
8.17.2.1WAN Insert Forwarding
The WAN Insert Queue can be user assigned to be multiplexed with only one LAN Queue Group. The Group
Scheduler for the assigned LAN Queue Group multiplexes the WAN Insert data with the data from the LAN Queue
Group.
8.17.3 OAM by Ethernet Destination Address (DA)
The device can be configured to directly trap broadcast, management multicast (01:80:C2:xx:xx:xx), and unicast
frames by Ethernet Destination Addresses for extraction by a microprocessor. The host microprocessor can be
user-programmed for parsing, interpreting, and responding to OAM messages.
8.17.4 OAM by IP Address
When a node on the network first tries to send a management frame to the device, the transmitting node would
normally broadcast an ARP request for the unknown IP address, asking for the network to resolve the IP address
to a physical MAC address. The device is able to trap ARP request using the Broadcast address trap. The user
software should examine each ARP request, and when appropriate, insert a frame in response to the ARP request
that will associate the device's management MAC address with the desired IP address. The network then transmits
frames with the DA value of the physical MAC address in the ARP response. The device would then trap the follow-
on frames by MAC (DA) address.
8.17.5 OAM by VLAN Tag
The device can be configured to trap frames with any number of user-programmed VLAN IDs in the VLAN table.
The VLAN table is accessed indirectly through the SU.VTC, SU.VTAA, and SU.VTWD registers. The
SU.VTWD.LVDW bit is used to indicate a VLAN ID (VID) value is to be extracted if received on the LAN interface.
The SU.VTWD.WVQFW bit is used to indicate a VLAN ID (VID) value is to be extracted if received on the WAN
interface. Note that VLAN trapping must also be enabled with the SU.WEM or SU.LPM registers.
8.17.6 SNMP Support
The device can be configured to trap unicast frames for extraction by the microprocessor. The host microprocessor
can be user-programmed for parsing, interpreting, and responding to SNMP messages. Hardware counters are
provided for supporting portions of RFC2819 (RMON), and portions of RFC1213 (MIB-II). See Section
8.19.2 for
more information on the MAC Management counters used for this purpose.