Access RAD ASMi-54 Installation And Operation Manual page 23

Installation and Operation Manual
•
Frame Admission
Mode
Admit all frames
Admit VLAN tagged
frames
Frames that pass this stage are submitted to the forwarding and learning
processes.
Learning Process
The learning process observes the source MAC address (SA) and the VID of the
received frame, and updates the forwarding database with the MAC VID pair and
with the bridge port that the frame was received from. The Forwarding Data Base
(FDB) is also referred to as a MAC table.
Entries in the MAC table can be dynamic (inserted by the learning process) or
static (inserted by configuration). A dynamic entry has an aging time associated
with it.
ASMi-54 Ver. 1.0
Enable: Performs ingress filtering according to VIDs. Only frames that
share a VID assigned to this bridge port are admitted
Disable: All frames are forwarded.
Only admitted frames that pass filtering are submitted to learning and
forwarding processes.
PVID Assignment: Is per bridge port configuration:
In VLAN-Aware mode, each received frame entering the bridge is
associated with a single VID. In case the received frame does not contain
a VLAN ID (untagged or priority only tagged frames), a specific PVID is
assigned to these frames before they pass to the forwarding process.
Accordingly, the untagged/priority tagged frames that have passed the
admission/ingress filtering, are tagged with PVID and proceed to the
forwarding process. Tagged frames will be double tagged with the PVID
only if Tag Stacking is enabled.
For untagged frames that were tagged during this process to VID=PVID,
the priority tag is assigned at the VLAN priority field, according to the
default priority configuration.
Table 1-1
summarizes the behavior of the ingress process:
Ingress
Filtering Mode
Enable
Disable
Enable
Disable
Table 1-1. Ingress Process
Bridge Behavior
VLAN tagged frames with a VID (or PVID for
untagged/priority tagged frames) that do not
include the bridge port in their VLAN member
set, are dropped.
All frames pass.
VLAN tagged frames with a VID that do not
include the bridge port in their member set are
dropped. Untagged/priority-only tagged frames
are dropped.
All VLAN tagged frames pass.
Untagged/priority-only tagged frames are
dropped.
Chapter 1 Introduction
Functional Description 1-7