MDS212 Datasheet, PDF (55/111 Pages) Zarlink Semiconductor Inc – 12-Port 10/100Mbps Ethernet Switch

MDS212
Data Sheet
deletion and VLAN port membership modification. VMAP is used by Frame Engine to forward multicast or
destination unknown unicast frames to multiple ports simultaneously.
31 27 26 25 24
RE
13 12 11
VLAN Port Enable [11:0]
0
Tag Enable [11:0]
Bit [11:0]VLAN Tag Enable [11:0]One bit for each Ethernet MAC Port
0 = disable, 1 = enable
Bit [12]Reserve
Bit [24:13]VLAN Port Enable [11:0]One bit for each Ethernet MAC Port, identifying the ports
associated with each VLAN. 0 = disable, 1 = enable
Bit [25]Reserve
Bit [26]RERemote Ports Enable: Indicate some members in the
remote device. 0=disable, 1=enable
Bit [29:31]Reserve
14.2.5 Port VLAN ID (PVID) Register
This register defines the Port VLAN ID (PVID) and priority for each port. PVID needs to be set up by
CPU software, and is used by MDS212 to decide the port’s VLAN ID and priority if the incoming packet is
VLAN untagged.
31
24 23
16 15
13 12 11
87
0
Priority
Port VLAN ID
Bit [11:0]:Port VLAN ID (PVID),
Bit [12]:Reserved
Bit [15:13]:Priority
Bit [31:16]:Reserved
15.0 IP Multicast
15.1 Introduction
IP Multicast permits an IP host (source) to transmit a single IP packet to multiple IP hosts (receivers). IP
Multicasting allows a source to send only one copy and the network ensures delivery to each member of the
specified multicast group. Network bandwidth is allocated more efficiently, as multiple copies of the same frame are
not transmitted between common ports.
The packet destined to an IP multicast group address determines the set of recipients. Hosts may choose to be
members of a number of multicasts, and hence select the multicast packets they wish to receive. They may
subscribe or unsubscribe to these multicast groups dynamically, using the Internet Group Management Protocol
(IGMP) that support automatic multicast group membership. IGMP is configured to create, update, and/or remove
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