System information

1. System Concepts
1-4 July 2004 4821-A2-GB21-00
Priority Groups
When entering tagged or untagged members of a VLAN that are DSL ports,
specify a priority group on the DSL port using the port-id:pg form. (See DSL Port
ID on page 1-2.) If only the DSL port number is specified then the VLAN is
mapped to priority group 1 for that DSL port. A VLAN can at most have only one
priority group per DSL port as a member of the VLAN.
The following illustrations show how priority groups affect upstream and
downstream traffic.
1:1 (Lowest Priority Group)
Default Priority
Por VLAN ID (PVID)
d
spv
VLAN
Tagged?
2
Frames are
forwarded to the
bridging and
classification
processes.
1:2
1:3
1:4
1:5
1:6
1:7
1:8 (Highest Priority Group)
Ingress Filter
optionally checks
that ingress frames
are tagged with a
VLAN ID defined for
this PG.
2
3
Frames are received
from a subscriber
interface on a VC.
Frames are assigned
to a PG based on the
VC.
3
4
Frames (VLAN tagged
and untagged) are
checked against the
acceptable frame type
rule for the PG.
4
Voice
Video 1
Video 2
Video 3
Video 4
PPPoE
Bridged
VC
Default
Data
VC 0/40
VC 1/33
VC 1/34
VC 1/35
VC 1/36
VC 0/62
VC 0/32
VC 0/35
Priority Group (PG)
VC - VLAN Upstream Flow Example
DSL Port 1
03-17462
d
spv
Discard
Frame
Acceptable
Frame
Type?
Ingress
Filter?
Filter Filter
Yes
No
Bridge and
Classification
VLAN 1
Forward
1
1
Untagged frames are
tagged with the PVID
and Default Priority
fields for the PG.
5
5