ZL50405GDC ZARLINK [Zarlink Semiconductor Inc], ZL50405GDC Datasheet - Page 48

• Manufacturer Part Number: ZL50405GDC
• Description: Managed5-Port 10/100 M Ethernet Switch
• Manufacturer: ZARLINK [Zarlink Semiconductor Inc]

The ZL50405 also provides a safe fail-over mode for port trunking automatically. If one of the ports in the trunking
group goes down, the ZL50405 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
For multicast packet forwarding, the device must determine the proper set of ports from which to transmit the
packet based on the VLAN and hash key.
Three functions are required in order to distribute multicast packets to the appropriate destination ports in a port
trunking environment.
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For example, port 0,1 and 2 belong to trunk group 0 and port 3 and 4 belong to trunk group 1. A single VLAN is
established in this system with port 0,1,2,3,4,5 and 6 as the members in the VLAN. When a multicast packet is sent
in from port 3, the ZL50405 select port 0,1,2,3,4,5 and 6 as potential destination based on the VLAN. Then port 3
and 4 are removed because they belong to the source port group (trunk group 1). Two ports from trunk group 0 will
be removed based on the hash key. In this example, we assume port 0 and 1 are removed. As a result, port 2,5 and
6 are the only outgoing ports for this multicast packet.
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 ZL50405.
1. Source or Destination MAC address based
2. Flow based
3. Port based
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
mirrored port. In the same way, if destination is selected, any packet received with mirroring MAC address as
destination MAC address will be copied to the mirrored port.
In flow based mirroring, a flow is established based on the source and destination mac address pair. When
enabled, a packet with source and destination address match the pre-programmed source and destination mac
Determining the VLAN group it is forwarding port per group.
The source port/group must be excluded from the forwarding.
Select one port per trunk group to forward the packet to. This selection is based on hash key described in
previous section.
Unicast Packet Forwarding
Multicast Packet Forwarding
Mirroring Features
Traffic Mirroring
Zarlink Semiconductor Inc.
ZL50405
48
Data Sheet