Access RAD ASMi-54 Installation And Operation Manual page 25

Installation and Operation Manual
The frame format can be configured for each VLAN and port:
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VLAN-Unaware Mode
In this mode the bridge forwarding ignores the VLAN ID of VLAN-tagged frames.
Each Ethernet packet received from each bridge port is forwarded according to its
destination MAC address.
Bridge Features
Bridge features include:
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Ingress Process
All frames are accepted in this mode: untagged, priority-tagged, or VLAN tagged.
Learning and forwarding is based on the MAC addresses, with no regard to the
VLAN. This mode is also known as transparent mode.
Learning Process
The learning process observes the source MAC address (SA) of the received frame
and updates the forwarding database (FDB) with the MAC address and the bridge
port that the frame was received from. (FDB is also referred to as MAC table).
The learning process inserts a new entry into the MAC table. This entry consists
of the MAC and bridge port.
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Aging Process
The aging process checks the forwarding MAC table periodically. Each dynamic
entry aging time period that has exceeded the configured Aging Time Limit is
deleted. The aging time period is the period of time since the last frame for this
ASMi-54 Ver. 1.0
VLAN-tagged: In this mode:
VLAN-tagged frames are transmitted unchanged.
Untagged frames are transmitted tagged with priority according to the
default priority of the ingress bridge port, and VID=PVID of the port from
which they entered.
Priority-tagged frames are transmitted tagged with original priority and
VID = PVID.
Untagged: In this mode, all frames are transmitted as untagged.
Learning and forwarding according to MAC address only
Learning of up to 2048 MAC addresses
Configuration of the aging time
VLAN tagged frames transparency (forwarding according to MAC only)
MAC table viewing (learned MACs)
If the MAC already exists for the same bridge port, the aging time will be
updated.
If the MAC already exists, but for a different bridge port, (dynamic entry) the
new entry will override the existing one.
Chapter 1 Introduction
Functional Description 1-9