MDS213 Datasheet, PDF (57/120 Pages) Zarlink Semiconductor Inc – 12-Port 10/100Mbps + 1Gbps Ethernet Switch

MDS213
Data Sheet
14.2.4.3 VLAN Port Mapping Table (VMAP)
The VLAN Port Mapping Table (VMAP) is an internal table within the MDS213. It contains 256 entries, one for each
VLAN, identified by an internal VLAN Index. The contents of this table are set up and maintained by CPU software
during VLAN creation, 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
13 12
0
RE _{VLAN Port Enable [12:0]}
TAG Enable [12:0]
Bit [12:0]VLAN Tag Enable [12:0]One bit for each Ethernet MAC Port
0 = disable, 1 = enable
Bit [25:13]VLAN Port Enable [12:0]One bit for each Ethernet MAC Port, identifying the ports
associated with each VLAN. 0 = disable, 1 = enable
Bit [26]RE Remote Ports Enable: Indicate some members in the remote
device.0=disable, 1=enable
Bit [31:27]Reserve
14.2.4.4 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 MDS213 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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