Functional Description
Packet Address (UNICAST_ADDRESS)
This is the 48-bit packet MAC address. All 48-bits are used in the lookup.
14.3.2.7.1.7 VLAN Table Entry
Table 14-17. VLAN Table Entry
71:62
61:60
59:48
47:27
26:24
23:19
18:16
15:11
10:8
7:3
2:0
Reserved
Entry
vlan_id
Reserved
Force
Reserved
Reg
Reserved
Unreg
Reserved
Vlan
Type (10)
Untagged
Mcast
Mcast
Member
Egress
Flood
Flood
List
Mask
Mask
Table Entry Type (ENTRY_TYPE)
10: VLAN entry
VLAN ID (VLAN_ID)
The unique identifier for VLAN identification. This is the 12-bit VLAN ID.
Force Untagged Packet Egress (FORCE_UNTAGGED_EGRESS)
This field causes the packet VLAN tag to be removed on egress (except on port 0).
Registered Multicast Flood Mask (REG_MCAST_FLOOD_MASK)
Mask used for multicast when the multicast address is found
Unregistered Multicast Flood Mask (UNREG_MCAST_FLOOD_MASK)
Mask used for multicast when the multicast address is not found
VLAN Member List (VLAN_MEMBER_LIST)
This three bit field indicates which port(s) are members of the associated VLAN.
14.3.2.7.2 Packet Forwarding Processes
There are four processes that an incoming received packet may go through to determine packet
forwarding. The processes are Ingress Filtering, VLAN_Aware Lookup, VLAN_Unaware Lookup, and
Egress.
Packet processing begins in the Ingress Filtering process. Each port has an associated packet forwarding
state that can be one of four values (Disabled, Blocked, Learning, or Forwarding). The default state for all
ports is disabled. The host sets the packet forwarding state for each port. The receive packet processes
are described in the following sections.
In the packet ingress process (receive packet process), there is a forward state test for unicast destination
addresses and a forward state test for multicast addresses. The multicast forward state test indicates the
port states required for the receiving port in order for the multicast packet to be forwarded to the transmit
port(s). A transmit port must be in the Forwarding state for the packet to be forwarded for transmission.
The mcast_fwd_state indicates the required port state for the receiving port as indicated in
The unicast forward state test indicates the port state required for the receiving port in order to forward the
unicast packet. The transmit port must be in the Forwarding state in order to forward the packet. The block
and secure bits determine the unicast forward state test criteria. If both bits are set then the packet is
forwarded if the receive port is in the Forwarding/Blocking/Learning state. If both bits are not set then the
packet is forwarded if the receive port is in the Forwarding state. The transmit port must be in the
Forwarding state regardless. The forward state test used in the ingress process is determined by the
destination address packet type (multicast/unicast).
In general, packets received with errors are dropped by the address lookup engine without learning,
updating, or touching the address. The error condition and the abort are indicated by the CPGMAC_SL to
the ALE. Packets with errors may be passed to the host (not aborted) by a CPGMAC_SL port if the port
has a set rx_cmf_en, rx_cef_en, or rx_csf_en bit(s).
1200
Ethernet Subsystem
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated