zl50411 Zarlink Semiconductor, zl50411 Datasheet - Page 51

• Manufacturer Part Number: zl50411
• Description: Managed 9-port Fast Ethernet Switch With Private Vlan
• Manufacturer: Zarlink Semiconductor

If a VLAN includes any of the ports in a trunk group, all the ports in that trunk group should be in the same VLAN
member map.
The ZL50411 also provides a safe fail-over mode for port trunking automatically. If one of the ports in the trunking
group goes down, the ZL50411 can redistribute the traffic over to the remaining ports in the trunk with software
assistance.
8.2
The search engine finds the destination MCT entry, and if the status field says that the destination port found
belongs to a trunk, then the trunk group number is retrieved.
The source port of the packet is checked against the destination trunk group. If the source port belongs to the
destination trunk group, the packet is discarded.
A hash key, based on some combination of the source and destination MAC addresses for the current packet,
selects the appropriate forwarding port, as specified in the Trunk_Hash registers. Each trunk has eight trunk_hash
registers which selects one of the potential eight outgoing ports. The hash key provides a pseudo flow identifier
which force the same flow to the same destination flow. As a result, the packet will always arrive in order.
8.3
Multicast frame forwarding is only slightly more complex than unicast frame forwarding in a port trunking
environment:
1. Determine the VLAN to which the multicast frame belongs.
2. Is the frame's source port a member of the VLAN? If so, exclude that port. Is the frame's source port a member
3. Finally, among the still-eligible members of the VLAN that belong to trunk groups, exclude all but one port from
Example: Ports 0, 1, and 2 belong to trunk group A. Ports 3 and 4 belong to trunk group B. A multicast frame is
received from source port 3. Suppose that the VLAN of the frame has member ports 0, 1, 2, 3, 4, 5, and 6.
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9.0
See Traffic Mirroring application note, ZLAN-50, for more information.
9.1
Packets can be mirrored (duplicated) for network monitor purpose and/or network debug purpose. Three types of
mirroring is available in ZL50411.
1. Source or Destination MAC address based
2. Flow based
3. Port based (RMII mode only)
In source or destination mac address based mirroring, the “M” bit of the mirroring MAC address in the MCT is set.
Also, the user need to specify the mirroring MAC address is source or destination of the packet. If source is
selected, any packet received with the mirroring MAC address as source MAC address will be copied to the
of a trunk group? If so, exclude all other ports in that group as well.
each trunk group. This selection is based on hashing or round robin, as in unicast frame forwarding.
Ports 0, 1, 2, 3, 4, 5, and 6 are potential destination ports for the frame.
Port 3 is excluded as a destination because it is the frame's source port.
Port 4 is excluded as a destination because it belongs to the same trunk group as port 3.
Two of the three ports in trunk group A must now be excluded. The ZL330ENG hashing algorithm is applied,
and in this example, assume that ports 0 and 1 are excluded.
Therefore, ports 2, 5 and 6 comprise the final set of destination ports for the multicast frame.
Unicast Packet Forwarding
Multicast Packet Forwarding
Mirroring Features
Traffic Mirroring
Zarlink Semiconductor Inc.
ZL50411
51
Data Sheet