UTStarcom iSpirit 3026 Manual page 53

If the received packet is tagged with a nonzero VID, the VLAN it belongs to is identified by the
VID; if the packet is non-tagged or with a VID of 0, if the input port is an untagged member port
of a VLAN, this VLAN is the one that the packet belongs to; otherwise, if the input port is not an
untagged member of any VLAN, the packet will be discarded.
(2) To check packet type:
If the received packet has a destination MAC address of FF:FF:FF:FF:FF:FF, it's a broadcast
th
packet; If not broadcast while have a destination MAC address with the 40 bit being 1, it's a
multicast packet; Otherwise, it's a unicast packet.
(3) To determine output ports:
For a broadcast packet, the output ports include all member ports of the VLAN that the packet
belongs to.
For a multicast packet, firstly search the hardware Layer 2 multicast transmission table based on
the multicast MAC address and the VLAN it belongs to. If matching multicast entries are found,
the intersection of output ports of the multicast entries and member ports of the VLAN are the
output ports for the packet; If no common port, the packet will be discarded; If no multicast entry
is found, the output ports will be determined based on the transmission mode of Layer2
hardware multicast transmission table: for unregistered multicast transmission mode, multicast
packets are handled the same as for broadcast packets, i.e., the output ports include all member
ports of the VLAN the packet belongs to; for registered mode, there will no output port, and the
packet will be discarded.
For a unicast packet, firstly search the hardware Layer 2 transmission table based on the
destination MAC address and the VLAN it belongs to. If matching entries are found, the
intersection of output ports of the entries and member ports of the VLAN are the output ports for
the packet; If no common port, the packet is discarded; If no entry is found, the packet will be
handled the same as for broadcast packets, i.e., the output ports include all member ports of the
VLAN the packet belongs to.
(4) To send a packet
The packet will be sent to all output ports determined in the previous step.
If a output port is an untagged member of the VLAN the packet belongs to, the packet will be
sent without a VID tag; Otherwise, if tagged member, the packet will be tagged with the VLAN
ID.