zl50405 Zarlink Semiconductor, zl50405 Datasheet - Page 40

• Manufacturer Part Number: zl50405
• Description: Managed5-port 10/100 M Ethernet Switch
• Manufacturer: Zarlink Semiconductor

The value of the TPID of the Provider VLAN tag is not assigned in the IEEE 802.1ad standard. The ZL50405
provides a global configurable TPID but only supports the Extreme EtherType TPID (i.e. the stacked VLAN tag
cannot equal 0x81-00).
See Stacked VLAN application note, ZLAN-82, for more information.
5.10
The ZL50405 supports IP Multicast Filtering by:
•
•
The purpose of IP multicast filtering is to optimize a switched network performance, so multicast packets will only
be forwarded to those ports containing multicast group hosts members and routers instead of flooding to all ports in
the subnet (VLAN).
The ZL50405 with IP multicast filtering/switching capability not only passively monitor IGMP Query and Report
messages, DVMRP Probe messages, PIM, and MOSPF Hello messages; they also actively send IGMP Query
messages to learn locations of multicast routers and member hosts in multicast groups within each VLAN.
See IP Multicast Switching application note, ZLAN-52, for more information.
6.0
6.1
When a frame enters the device at the RxMAC, the RxDMA will move the data from the MAC RxFIFO to the FDB.
Data is moved in 8-byte granules in conjunction with the scheme for the SRAM interface.
A switch request is sent to the Search Engine. The Search Engine processes the switch request.
A switch response is sent back to the Frame Engine and indicates whether the frame is unicast or multicast, and its
destination port or ports. On receiving the response, the Frame Engine will check all the QoS related information
and decide if this frame can be forwarded.
Passively snooping on the IGMP Query and IGMP Report packets transferred between IP Multicast Routers
and IP Multicast host groups to learn IP Multicast group members, and
Actively sending IGMP Query messages to solicit IP Multicast group members.
Data Forwarding Summary
Frame Engine
IEEE 802.1Q Tagged
Ethernet Frame
IEEE 802.1Q-in-Q Tagged
Ethernet Frame
Dest MAC
(6 Bytes)
IP Multicast Switching
Dest MAC
(6 Bytes)
* Provider Tag TPID = Configurable on per device basis
Source MAC
(6 Bytes)
Source MAC
(6 Bytes)
IEEE 802.1Q Tag TPID = 0x8100
Tag Protocol ID
(0x88A8*)
Tag Protocol ID
VLAN
(0x8100)
VLAN
Figure 10 - Q-in-Q Tagged Ethernet Frame
Provider
(P-VLAN)
802.1Q Tag
Tag
IEEE
VLAN TCI
(2 Bytes)
VLAN TCI
Zarlink Semiconductor Inc.
(2 Bytes)
ZL50405
Tag Protocol ID
40
(0x8100)
Type/Length
VLAN
(2 Byte)
802.1Q Tag
IEEE
VLAN TCI
(2 Bytes)
Data
Type/Length
(2 Byte)
Data
Data Sheet