Access RAD ASMi-54 Installation And Operation Manual page 22

Chapter 1 Introduction
Ethernet Access (Bridge)
ASMi-54 has a multi-port bridging capability handling up to six bridge ports. The
Bridge supports two modes of operation:
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The mechanism of each mode can be described as five different processes:
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Bridge features and these five processes are described below for each mode.
VLAN-Aware Mode
This mode enables the creation of sub-groups of bridge ports within the bridge.
Each sub-group is defined per VLAN and is associated with a unique VLAN ID
(VID). Frames containing a VID can be forwarded only between bridge ports that
are members of this specific VLAN, enabling a total separation between different
VLAN users within the same bridge.
Bridge Features
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Ingress Process
The ingress process is composed of three steps:
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1-6 Functional Description
VLAN-Aware
VLAN-Unaware.
Ingress: Checks each frame entering the bridge to decide if and how this
frame should be passed on to the forwarding process
Learning: Learns new MAC table entries (MAC only or MAC VID pairs)
Aging: Checks the forwarding MAC table periodically
Forwarding: Decides to which bridge port/ports to forward the frame
Transmission (VLAN-Aware mode only): Selects the format of the transmitted
frame at the output port: with VLAN ID (tagged) or without VLAN ID
(untagged).
Full VLAN-Aware bridge in accordance with 802.1Q
Learning and forwarding according to MAC address and VID
Learning of up to 1,024 MAC table entries (MAC + VID pairs)
Configuration of the aging time
MAC table viewing (learned MACs).
Frame Admission: Two modes of operation (configured per bridge):
Admit All Frames: All frames arriving from the port are admitted and
proceed to the ingress filtering process. PVID is assigned to untagged or
priority only tagged frames.
Admit Only VLAN Tagged Frames: Only VLAN tagged frames are admitted
and allowed to proceed to the ingress filtering process. Untagged or
priority-only tagged frames are discarded.
Ingress Filtering: Works in one of the following modes (configured per bridge
port):
Installation and Operation Manual
ASMi-54 Ver. 1.0